Organic growing

Main Sources of Organic Matter for the Garden

Important nuance (C:N ratio): Microorganisms decomposing organic matter consume nitrogen. If you apply materials with high carbon and low nitrogen (straw, fresh sawdust, dry leaves), they can "draw" nitrogen from the soil, causing temporary nitrogen starvation in tomatoes. Therefore, such materials should be composted beforehand or mixed with nitrogen‑rich components (manure, grass, green manures). For tomatoes, ideal C:N of applied organic matter is in the range 20–30:1 (Hochmuth & Sideman, 2023). Well‑rotted manure has C:N ≈ 20:1, compost 10–20:1, straw 60–80:1. Keep this in mind when planning.

How to Choose a Green Manure for Tomatoes

Practical recommendations:

• For most regions, the best scheme is to sow winter rye or a vetch‑rye mix in September, and in spring, 2–3 weeks before planting tomatoes, mow or dig the green mass to a depth of 10–15 cm (Gavrish, 2005). During this time organic matter begins to decompose, and by the time seedlings are planted the soil is ready.
• In warm regions (tropics, subtropics) you can use fast‑growing legumes in summer, then plant tomatoes in autumn.
• If you are just starting on a plot, sow a "health‑restoring" mix for a season: mustard + vetch + oats – it improves structure and cleans the soil.

Nitrogen‑Rich Materials

Important: in the European Union, regulations limit nitrogen from manure to 170 kg/ha per year (Dorais & Schwarz, 2018). For a hobby garden this ≈ 0.5–0.8 kg N per 100 m², corresponding to 5–8 kg of well‑rotted manure or compost per m².

Phosphorus and Complex Materials

Potassium Materials

Complex Materials with Good NPK Balance

• Compost (C:N ≈ 10–20:1, NPK content ~0.5–2 % each) – universal base.
• Sapropel (lake sediments) – contains N, P, K, micronutrients.
• Vermicompost (worm compost) – rich in humic acids and microflora.
• Green manures – their value lies in releasing nutrients as they decompose in rhythm with tomato growth.

Micronutrients: How to Supplement Without Ready‑Made Chelates?

In organic soil with pH 6.0–6.8 and sufficient organic matter, micronutrients are almost always available (Dorais & Schwarz, 2018). But if there are signs of deficiency:

• Iron: apply iron chelates (allowed in organics) or, as a last resort, ferrous sulfate, but its effectiveness is lower.
• Boron: 1–2 g of borax (Na₂B₄O₇·10H₂O) per m² dry or foliar spray with 0.1 % boric acid solution (Hochmuth & Sideman, 2023).
• Manganese, zinc, copper: usually present in compost and manure. If spot applications are needed, use chelates or sulfates.
• Calcium: in organics use dolomite lime, eggshell (washed and ground), gypsum (allowed).

Phase 1. Soil Preparation (Autumn–Spring)

The main application of organic matter is the key to success. This lays the long‑term nutrient reserve.

• In autumn (2–3 months before planting): spread 5–10 kg/m² of compost or well‑rotted manure over the area and work into the top layer (15–20 cm). If soil is acidic, simultaneously add dolomite lime (200–400 g/m²). This starts the decomposition process, and by spring the soil will be living and balanced.
• In spring (2–3 weeks before planting): surface loosen and, if necessary, add another 2–3 kg/m² of compost if the plot is heavily depleted.

Phase 2. Seedlings and Planting

• In the planting hole: add 1–2 handfuls of humus or vermicompost, 1 tablespoon of bone meal (phosphorus source), 1–2 tablespoons of ash (potassium + micronutrients). Mix thoroughly with soil to avoid root contact with pure organics (can burn). Leaf mould also works well in holes.
• 10–14 days after planting: first "starter" feed – water with liquid manure extract (1:10) or fermented grass (1:5–1:10). This provides nitrogen for active vegetative growth.

Phase 3. Start of Flowering (1–2 trusses)

• Potassium feed: apply ash (100–150 g/m², scattered around roots and worked into top layer) or water with ash extract (1–2 cups of ash per 10 L water, steep 24 h, apply 0.5–1 L per plant). Potassium improves fruit set.
• Boron: for better pollination, foliar spray with 0.1 % boric acid (1 g per 1 L water) on leaves in the evening. Repeat after 7–10 days.

Phase 4. Active Fruit Growth (Mass Fruiting)

• Potassium and calcium: every 2–3 weeks feed with potassium extract (ash or comfrey) and, if signs of blossom‑end rot appear, apply ground eggshell (dust into soil) or spray with 1 % calcium nitrate solution (in some countries allowed in organics). Calcium reduces blossom‑end rot risk (Blancard, 2012).
• Nitrogen – only if needed: if the plant is "overgrowing" (strong dark‑green leaves, thick stems, poor fruit set), omit nitrogen feeds. If leaves, especially older ones, turn pale, apply a weak nettle extract.
• Supporting microflora: once a month apply bio‑products (Trichoderma, Bacillus subtilis) or water with compost extract (1–2 L per plant). This maintains beneficial bacteria activity.

Foliar Feeding – When Is It Needed?

Foliar feeding (leaf spraying) does not replace root feeding but can be indispensable in emergencies:

• For quick delivery of boron, calcium, or iron in case of deficiency.
• When soil is cold and roots work poorly, while the plant needs a boost (Heuvelink, 2018).

Rule: solutions for spraying should be weaker – 0.5–1 % concentration (5–10 g per 1 L water). Spray in the evening or on cloudy days to avoid burns.

1. For Green Growth (Early Spring – Early Summer)

• Manure extract: 1:10, apply under root, once every 10–14 days.
• Nettle extract: 1:5 concentrate, dilute 1:10 before watering.
• Apply well‑rotted manure or compost around the plant base (2–3 L per plant).

2. For Flowering and Fruit Set

• Ash solution: 2 cups ash per 10 L water, steep 24 h, strain. Apply 0.5 L per root once every 2 weeks.
• Foliar boric acid: 1 g per 1 L water, spray 1–2 times at 7‑day intervals.
• Compost tea: steep 1 part mature compost in 5 parts water for 24–48 h, strain, use for watering.

3. For Fruit Swelling

• Comfrey or seaweed extract – rich in potassium.
• Ash solution (potassium + micronutrients), can be combined with calcium feed (eggshell, dolomite, 1 % calcium nitrate).
• Supporting feed: compost tea or vermicompost extract (1:10) once every 2–3 weeks – maintains soil microflora.

Bacillus subtilis – hay bacillus

This is one of the most studied and widely used beneficial bacteria in organic farming (Akhatov, 2010; Blancard, 2012).

What it does:

• Produces antibiotics that inhibit many fungal pathogens (late blight, Alternaria, Fusarium, Verticillium, grey mould).
• Colonises the rhizosphere and competes with pathogenic bacteria for nutrients.
• Stimulates root growth and enhances plant immunity by inducing systemic resistance – tomato becomes less susceptible to diseases.

How to apply: Bacillus subtilis is sold as liquid concentrates, dry powders, or tablets. Common preparations (names may vary by country) contain strains selected for tomato protection.

• Seed treatment: soak seeds in bacterial suspension for 1–2 hours before sowing, then dry in the shade (Hochmuth & Sideman, 2023).
• For soil: water under root with the solution 1–3 days before sowing or transplanting, then repeat after 2–3 weeks.
• For spraying: on leaves for preventive purposes during the season, at 10–14‑day intervals.

Important: Bacillus subtilis is a living culture. It is active above 15 °C and needs a moist environment. Do not mix with copper‑containing preparations – they kill it.

Pseudomonas fluorescens – root defender

This genus of bacteria is also widely used in organic farming (Mattoo, 2017). They:

• Produce siderophores – compounds that bind iron, making it unavailable to pathogenic fungi (e.g., Fusarium).
• Produce antibiotics (phenazines) that inhibit many root rots.
• Stimulate plant growth by releasing phytohormones.

How to apply: usually as liquid cultures (titre at least 10⁹ cells/mL). Used for root watering at transplanting and during active growth. Compatible with some bio‑products, but not with chemical fungicides.

Trichoderma – the "predator fungus"

Trichoderma is not just a beneficial fungus but a true "hunter" of pathogenic fungi (Akhatov, 2010; Blancard, 2012).

How it works:

• Germinates on root surfaces and nutrient media, releasing antibiotics (gliotoxin, trichodermin).
• Trichoderma hyphae coil around the mycelium of pathogenic fungi (Fusarium, Phytophthora, Rhizoctonia, Sclerotinia) and penetrate inside, digesting them.
• Stimulates plant growth and enhances stress resistance.

How to apply:

• In soil: add to planting holes (1–2 granules or 1–2 mL suspension per plant).
• For planting material: soak seedling roots in trichoderma suspension before transplanting.
• For stem damage (cracks, leaf scars): paint with trichoderma suspension mixed with chalk or clay to protect against grey mould (Blancard, 2012).
• Water soil with trichoderma solution 1–3 days before transplanting.

Effectiveness: Trichoderma works particularly well on steamed or sterilised soils with fewer competitors. In microbe‑rich soil its effect may be weaker, but it still reduces root rot development.

Mycorrhizal Fungi

Mycorrhiza is a symbiosis of fungi with plant roots. The fungal mycelium penetrates soil hundreds of times more than roots, helping tomatoes obtain water and mineral elements (especially phosphorus) from hard‑to‑reach areas (Dorais & Schwarz, 2018).

In organic farming, mycorrhizal products (based on Glomus fungi) can be useful when transplanting into poor soils. They increase tomato tolerance to drought and soil‑borne diseases.

Predatory Mites – Against Spider Mites

The spider mite is one of the most common tomato pests in hot, dry weather. In organics, it is controlled using the predatory mite Phytoseiulus persimilis and its relatives (Amblyseius, Neoseiulus).

Principle: the predator reproduces faster and feeds more actively than its prey. At 25–30 °C and 70–90 % humidity, it eliminates spider mites in 2–3 weeks.

How to apply: release predatory mites into infestation spots at a rate of 10–50 individuals per m² (depending on mite density). Repeat releases every 2–3 weeks until full control. Suitable for greenhouses and protected cultivation.

Parasitic Wasps (Encarsia, Eretmocerus) – Against Whitefly

Whitefly (especially tobacco and glasshouse whitefly) is a dangerous pest and virus vector. Encarsia formosa and Eretmocerus eremicus are effective against it (Mattoo, 2017).

Females of these wasps lay eggs inside whitefly larvae, and the developing parasitoid kills the host. To control whitefly in greenhouses, release Encarsia weekly (5–10 individuals per m²) until control is achieved. In open ground, less frequent, but you can attract them by planting nectar‑producing plants (dill, buckwheat, phacelia) nearby to feed adult wasps.

Predatory Bugs (Orius, Macrolophus) – Against Thrips and Aphids

Thrips transmit tomato spotted wilt virus. In organics, they are controlled with Orius laevigatus and other predatory bugs.

They actively eat thrips larvae and adults, as well as aphids and spider mites. Release Orius at first signs of thrips, at 1–2‑week intervals, 5–10 individuals per m².

Important: success of biocontrol depends on temperature and humidity. Many entomophages require temperatures above 18–20 °C and 60–80 % humidity. Consider this when planning releases (especially in greenhouses).

How to Attract Beneficial Insects Naturally (Without Purchasing)

You don't have to buy entomophages. You can create conditions for them to colonise your plot.

• Plant nectar‑producing flowers: dill, coriander, phacelia, mustard, buckwheat, sunflower, marigolds. They attract lacewings, parasitic wasps, ladybugs.
• Maintain natural shelters: shrubs along borders, compost heaps, stones – places for beneficial insects to overwinter.
• Avoid broad‑spectrum applications: do not use insecticides, even permitted ones, unless absolutely necessary. They kill both beneficial and harmful insects.
• Leave some plants untouched: for example, at plot edges – to preserve food sources for entomophages.

1. Late Blight (Phytophthora infestans)

Symptoms: on leaves – diffuse brown spots, first on lower leaves then all over. On stems – dark brown elongated patches. On fruits – firm brown spots that enlarge rapidly (Blancard, 2012). Under high humidity, a whitish mould appears on affected tissues – fungal sporulation.

When it appears: second half of summer, during cool (13–18 °C) and wet weather (dew, fog, rain). Particularly dangerous in regions with frequent rainfall and in dense plantings.

Prevention (key!):

• Choose resistant hybrids: there are varieties and hybrids with genetic resistance to late blight (e.g., F1 Semko 98, F1 Semko 100), significantly reducing epidemic risk (Akhatov, 2010; Gavrish, 2005).
• Crop rotation: do not plant tomatoes after potatoes or near them – late blight is common to both.
• Air circulation: in greenhouses, ventilate regularly, avoid condensation on leaves. In open ground, choose well‑aired sites.
• Mulching: mulch layer (straw, mown grass) prevents fruit infection from soil.
• Watering: only under root, by drip, in the morning, so leaves dry during the day.
• Remove lower leaves: regularly remove lower leaves touching the soil to improve air circulation.

Allowed organic remedies (at first signs):

• Copper‑based products (Bordeaux mixture, copper oxychloride) – at minimum doses, no more than once every 7–10 days. Copper inhibits spore germination. Important: copper accumulates in soil, so use only when crop loss is imminent (Blancard, 2012).
• Bioproducts based on Bacillus subtilis (e.g., Fitosporin‑M, Alirin‑B, Gamair) – spray every 10–14 days preventively. They create a protective film on leaves that suppresses pathogen development (Akhatov, 2010).
• Garlic or horsetail extract – 200–300 g crushed material per 10 L water, steep 24 h, strain, add soap (20 g) for adhesion. Spray every 5–7 days. This inhibits fungal development but does not cure completely (Hochmuth & Sideman, 2023).

2. Alternaria, or Early Blight (Alternaria solani, A. tomatophila)

Symptoms: on leaves – dark brown spots with concentric rings ("targets"), 1–2 cm in diameter, with yellow halo. On stems – elongated dark spots. On fruits – sunken dark spots, often near the pedicel. In wet weather, spots become covered with dark velvety mould (Blancard, 2012; Akhatov, 2010).

When it appears: during flowering and fruiting, especially in warm (25–30 °C) and humid weather, alternating rain and heat.

Prevention:

• Crop rotation – return tomatoes to same place no earlier than 3–4 years.
• Balanced nutrition – avoid nitrogen excess, which makes tissues soft.
• Remove affected leaves and fruits at first signs, remove from plot (not into compost unless heat‑treated).
• Mulching – prevents lower leaves from contacting soil, where spores originate.

Organic control methods:

• Same copper‑based products (Bordeaux mixture) – when first spots appear.
• Bioproducts with Bacillus subtilis – preventive every 10–14 days.
• Sulfur treatment (colloidal sulfur) – 0.3–0.5 % solution, especially against powdery mildew, which sometimes accompanies Alternaria.
• Tansy or wormwood extract – spraying to boost overall immunity (Hochmuth & Sideman, 2023).

3. Cladosporiosis, or Leaf Mould (Mycovellosiella fulva = Fulvia fulva)

Symptoms: on upper leaf surface – yellowish rounded spots that turn brown. On lower surface – olive‑brown velvety mould. Leaves curl and dry (Blancard, 2012; Akhatov, 2010). Mainly leaves, rarely fruits. Especially dangerous in greenhouses at high humidity (>75–80 %) and 22–25 °C.

Prevention:

• Grow resistant hybrids – most modern greenhouse hybrids have genes for resistance to Cladosporium (e.g., F1 Evpator, F1 Raisa, F1 Blagovest, etc.) (Gavrish, 2005). In open ground less common.
• Regular ventilation of greenhouses, reduce humidity.
• Remove lower affected leaves and remove from plot.
• Do not overcrowd – spacing at least 50–60 cm between plants in row.

Organic remedies:

• Spray with bioproducts (Bacillus subtilis) – effective preventively and at early stages.
• Sulfur products – colloidal sulfur (0.3 %) at first signs.
• Soda with soap – 10 g baking soda + 20 g soap per 1 L water, spray every 5–7 days to create alkaline environment unfavourable to the fungus.

4. Fusarium Wilt (Fusarium oxysporum f. sp. lycopersici)

Symptoms: yellowing and wilting of leaves, starting from lower, often on one side. Stem cross‑section shows darkened vascular tissue (Blancard, 2012; Akhatov, 2010). At high temperature (27–28 °C) plants may die within days.

Spread: fungus lives in soil, enters through roots (especially wounds caused by nematodes). Particularly dangerous in warm regions, under tomato monoculture, and on acidic sandy soils.

Prevention (main method, no cure):

• Use resistant hybrids – almost all modern hybrids have Fusarium resistance genes (F‑genes). Indicated as F1, F2 in catalogues (Gavrish, 2005).
• Long crop rotation – return tomato to same place no earlier than 4–5 years.
• Maintain soil pH 6.5–7.0 – disease develops more strongly in acidic soils.
• Soil disinfection (solarisation, steam) in greenhouses when replacing soil.
• Preventive watering with bioproducts (Trichoderma, Bacillus subtilis) at transplanting – they reduce soil pathogen levels.

Organic remedies: no direct cure, only slow development by raising pH (liming) and improving drainage. Remove infected plants completely to avoid accumulating infection in soil.

5. Verticillium Wilt (Verticillium dahliae, V. albo-atrum)

Symptoms: similar to Fusarium, but wilting is less acute. Lower leaves yellow at edges (V‑shaped), then turn brown and dry. Stem cross‑section shows vascular browning, but not as dark as in Fusarium. Often disease develops slowly, plants do not die but yield declines (Blancard, 2012).

Prevention:

• Resistant hybrids (with Ve gene) – many modern varieties have this resistance.
• Crop rotation.
• Liming acidic soils.
• Avoid planting after potato, pepper, eggplant, strawberry – they are also susceptible.

6. Bacterial Diseases (Bacterial Canker, Bacterial Spot)

Symptoms:

• Bacterial canker (Clavibacter michiganensis): wilting of individual leaf lobes, white spots with dark centre on fruits ("bird's eye"), dark cracks on stems (Blancard, 2012; Akhatov, 2010).
• Bacterial spot (Xanthomonas vesicatoria): small (1–2 mm) black spots on leaves, stems and fruits, with yellow halo. Fruit spots raised, scab‑like.

Prevention (key):

• Use healthy seeds – soak in hot water (50 °C, 25 min) or 1 % potassium permanganate before sowing.
• Do not overhead sprinkle – bacteria spread with water droplets.
• Remove and destroy infected plants at first signs.
• Observe crop rotation and do not plant tomatoes after peppers and potatoes.
• Treat with copper‑based products (Bordeaux mixture, copper oxychloride) preventively, especially after rain.

Bioproducts: Bacillus subtilis and Pseudomonas fluorescens can inhibit bacterial development, but effectiveness is limited. Rely on prevention and crop rotation.

7. Viral Diseases (Tomato Mosaic, Cucumber Mosaic, Tomato Spotted Wilt)

Symptoms:

• Mosaic (ToMV, CMV): mottled leaf colour (light and dark patches), distortion (thread‑like, fern‑like), uneven ripening and necrosis on fruits.
• Spotted wilt (TSWV): ring‑shaped brown spots on leaves and fruits, top wilting, stunting.

Prevention:

• Use only resistant hybrids (e.g., to TMV – with Tm‑22 gene).
• Destroy vectors (aphids, whiteflies, thrips) using biological methods (releasing entomophages, yellow sticky traps, soap sprays).
• Isolate tomato plantings from other nightshades, especially potato and tobacco.
• Sterilise tools before use (alcohol or 1 % potassium permanganate).
• Remove infected plants at first signs.

No cure – only prevention. In greenhouses, milk whey (10 % solution) with micronutrients can be used as a preventive – it forms a film on leaves that reduces virus entry (Akhatov, 2010).

Blossom‑end Rot

Symptoms: dark sunken spot at the blossom end of the fruit, enlarging and darkening. Often occurs in hot, dry weather or with sharp moisture fluctuations (Blancard, 2012; Hochmuth & Sideman, 2023).

Cause: calcium deficiency in fruits due to:

• Irregular watering (too dry then too wet).
• Excess nitrogen or potassium, competing with calcium.
• High temperature increasing transpiration.

How to prevent:

• Regular, uniform watering (no drying).
• Mulching to retain moisture.
• Foliar spray with 1 % calcium nitrate on leaves and fruits (allowed in some countries).
• Incorporate ground eggshell or dolomite lime (calcium sources) into soil well before planting (Hochmuth & Sideman, 2023).

1. Aphids (common potato, peach, melon aphids)

Appearance: small (1–3 mm) insects, greenish, yellowish, or pinkish. They live in colonies on leaf undersides, young shoots, and inflorescences. They excrete sticky "honeydew" on which sooty mould grows – leaves and fruits blacken (Akhatov, 2010; Blancard, 2012).

Signs: leaf curling, yellowing, sticky residue, ants (they feed on honeydew and spread aphids). Heavy infestation causes stunting, tip deformation.

Danger: suck sap, weaken plants. Main danger – they transmit viruses (mosaic, aspermy), making them especially dangerous (Blancard, 2012).

Biological control:

• Release parasitic wasps (Aphidius colemani, A. matricariae, Lysiphlebus testaceipes): females lay eggs inside aphids. Infected aphids turn into dark "mummies" (Akhatov, 2010). Release 0.5–1 individuals per m², in hot spots 2–5 per m², at 5–7‑day intervals. Effective in greenhouses and protected cultivation.

• Predatory midge Aphidoletes aphidimyza: larvae eat aphids. Release at 1 larva per 5–10 aphids. Works well above 60 % humidity and day length >14 h (Akhatov, 2010).

• Lacewing (Chrysoperla carnea): larvae are voracious predators of aphids, mites, and insect eggs. Attract by planting flowering plants nearby (dill, phacelia), or buy larvae from bio‑laboratories.

• Ladybirds (Coccinellidae): both adults and larvae actively eat aphids. Attract by providing shelters (bushes, weeds on borders) and avoiding insecticides.

Natural products:

• Soap solution: 20–30 g of household or potassium soap per 1 L water. Spray on leaves, thoroughly wetting colonies. Soap breaks down the protective wax layer of aphids. Repeat every 3–5 days until gone (Hochmuth & Sideman, 2023).

• Garlic or onion extract: 200 g crushed garlic per 10 L water, steep 24 h, strain, spray. Repels aphids and many other pests.

• Tobacco extract (repellent): 50 g dry tobacco per 1 L hot water, steep 24 h, strain, dilute 1:1, add soap. Do not apply on fruits during ripening.

• Oil emulsions: 1–2 % vegetable oil (100–200 mL per 10 L water) with soap blocks aphid respiration. Apply in the evening to avoid sunburn.

2. Whitefly (glasshouse, tobacco)

Appearance: adults – tiny (1–1.5 mm) white moths that fly up when plants are disturbed. Larvae – flat pale scales on lower leaf surfaces, motionless, like tiny wax droplets (Akhatov, 2010; Blancard, 2012).

Signs: sticky film on leaves, black sooty mould, yellowing and drying of leaves. In greenhouses reproduces year‑round, up to 10 generations per season.

Danger: suck sap, soil fruits and leaves with sticky excreta, transmit viruses (tomato yellow leaf curl, mosaic).

Biological control (very effective in greenhouses!):

• Parasitic wasp Encarsia formosa: females lay eggs in whitefly larvae. Infected larvae turn black. Release preventively at 5–10 individuals per m², weekly, for 4–6 weeks. In hot spots up to 50 per m² (Mattoo, 2017; Akhatov, 2010).

• Eretmocerus eremicus – another whitefly parasitoid, especially effective against tobacco whitefly (Bemisia tabaci). Applied similarly to Encarsia.

• Predatory bug Macrolophus caliginosus: feeds on whitefly eggs and larvae, also aphids, thrips, mites. Release 2–5 individuals per m².

• Predatory mite Amblyseius swirskii: feeds on whitefly eggs and small larvae, also thrips. Effective at 20–30 °C.

Traps:

• Yellow sticky traps: adult whiteflies are attracted to yellow. Hang at canopy level from early spring, at 1 trap per 5–10 m². They won't eliminate all but help monitor and reduce numbers (Akhatov, 2010).

Natural products:

• Soap solution (as for aphids) – helps wash off larvae and disrupt adult respiration.
• Pyrethrum (extract of Dalmatian chrysanthemum) – contact insecticide permitted in organics. Acts quickly but short‑lived. Use only in severe outbreaks, strictly as labelled.
• Garlic or onion extract – additional repellent.

Agronomy: in greenhouses, remove all plant debris between crops, disinfect structures and soil. Whitefly cannot survive without living plants.

3. Thrips (western flower thrips, tobacco thrips, tomato thrips)

Appearance: very small (0.5–2 mm) elongated insects, light yellow or brown. Tiny and mobile, hard to see with naked eye. Larvae even smaller, yellowish. Characteristic sign – black faecal dots on leaves (Blancard, 2012; Akhatov, 2010).

Signs: silvery streaks on leaves, tiny light spots, then brown necroses. Leaves deform. On fruits – spots with "rings", silvery speckling ("sunburn"), deformation (Blancard, 2012). Flowers drop.

Danger: suck cell sap, cause loss of turgor and deformation. Main danger – transmit tomato spotted wilt virus (TSWV), one of the most dangerous viruses (Blancard, 2012; Mattoo, 2017).

Biological control:

• Predatory bug Orius laevigatus (and other Orius species): feeds on thrips, aphids, mites. Release at first signs of thrips, 5–10 individuals per m², at 1‑2‑week intervals. Effective above 18 °C. Especially good in greenhouses (Akhatov, 2010).

• Predatory mites Amblyseius cucumeris, A. swirskii, A. limonicus: feed on thrips larvae. Release preventively at 50–100 per m² (scatter on plants or in sachets). Works well at 20–25 °C and 60–80 % humidity. On tomatoes they orient to pollen; for better effect, dust pollen (birch, pine) on leaves (Dorais & Schwarz, 2018).

• Neoseiulus cucumeris – another effective thrips predator.

Traps:

• Blue sticky traps (not yellow): thrips are more attracted to blue. Place at foliage level, 2–4 traps per 100 m². For monitoring and partial adult capture (Akhatov, 2010).

Natural products:

• Sulfur (colloidal) – especially effective against thrips when combined with mite control.
• Pyrethrum – short‑lived contact insecticide, can reduce adult numbers.
• Soap solution – at early stages, but effectiveness against thrips is limited.

Agronomy: remove weeds around plantings, especially nightshades (they are reservoirs). In greenhouses – thorough cleaning between crops.

4. Cutworms (cotton, garden, tomato cutworms)

Appearance: cutworm caterpillars are large (up to 4–5 cm) green, grey‑brown, or yellowish, often with dark stripes along the body. They are nocturnal – hide at base of stems or inside fruits during the day (Akhatov, 2010; Blancard, 2012).

Signs: chewed leaves, holes in fruits (caterpillars eat cavities inside), shrivelled, blackened fruits. Entry holes with dark frass visible on fruits.

Biological control:

• Trichogramma (Trichogramma spp.) – tiny (0.5 mm) parasitic wasps that lay eggs in cutworm eggs. Release at start of moth flight (detected by pheromone traps or by first caterpillars). Rate: 100,000–200,000 individuals per hectare, in 2–3 releases at 5‑7‑day intervals. For garden, about 100–200 per 10 m² (Akhatov, 2010).

• Predatory shield bugs (Podisus maculiventris, Picromerus bidens): feed on caterpillars of all ages. Release 5–10 individuals per m² in breeding foci (Akhatov, 2010).

• Bacterial product Bacillus thuringiensis (B.t.) – the most effective "bio‑insecticide" against young caterpillars. The bacterium produces crystalline toxins that destroy the caterpillar's gut wall. Apply when first young caterpillars (1st‑2nd instar) are seen, spraying in the evening (caterpillars active at night). Repeat every 5–7 days. Safe for beneficial insects and warm‑blooded animals (Blancard, 2012).

• Nematodes Steinernema and Heterorhabditis – entomopathogenic nematodes (microscopic worms) that penetrate caterpillars and kill them with bacterial toxins. Soil drench or spray in the evening. Effective against caterpillars that enter soil to pupate.

Natural products:

• Pyrethrum – contact insecticide, but less effective against older caterpillars.
• Hot pepper or wormwood extract – repellent, deters moths from laying eggs.

Agronomy: dig soil in autumn and spring to destroy overwintering pupae. Remove plant debris and weeds – they serve as food plants for moths. Use pheromone traps to monitor moth flight and timely apply Bacillus thuringiensis (Akhatov, 2010).

5. Spider Mite (common, red)

Appearance: very small (0.3–0.5 mm), reddish or greenish‑yellow. Lives on leaf undersides, covering them with fine webbing. Eggs – tiny spheres, transparent or pearly (Blancard, 2012; Akhatov, 2010).

Signs: tiny yellowish or silvery dots on leaves, then leaves become marbled, brown, and dry. Webbing noticeable at heavy infestation. Most active in hot (above 28 °C) and dry (humidity below 50 %) weather.

Danger: suck cell contents, weaken plants, reduce yield.

Biological control:

• Predatory mite Phytoseiulus persimilis: the most effective specialised predator of spider mites. Female is red, reproduces fast (at 30 °C and 80 % humidity development in 3 days). Feeds on all stages of spider mite, destroying 5–20 per day. Release at 10–50 predators per m² at first signs, or 1–2 per m² preventively. Effective at 20–30 °C and >60 % humidity. In hot, dry weather effectiveness drops (Akhatov, 2010; Dorais & Schwarz, 2018).

• Amblyseius californicus (Neoseiulus californicus) – more tolerant to low humidity and high temperatures than P. persimilis. Can be used in combination.

• Predatory mite Typhlodromus pyri – suitable for open ground.

Natural products:

• Sulfur products (colloidal sulfur, Thiovit Jet): spray 0.3–0.5 % solution at first signs. Effective, but do not apply above 28 °C (leaf burn).
• Soap solution – at early stages, helps wash mites and destroy webbing.
• Oil emulsions (1–2 %) – block mite respiration. Use only evening or cloudy weather.
• Garlic, onion, hot pepper extracts – supplementary repellents.

Agronomy: maintain air humidity (spray paths in greenhouses), avoid soil drying. Regularly inspect leaf undersides. Remove heavily infested leaves and plants.

6. Tomato Russet Mite (Aculops lycopersici)

Appearance: microscopic (0.14–0.24 mm), spindle‑shaped, pale yellow to rusty brown. Invisible without lens. Lives on stems, leaves, fruits (Akhatov, 2010; Blancard, 2012).

Signs: brownish‑rusty coating on stems and leaves, thickening and corking of tissues. Stems crack, leaves brown, curl and dry. On fruits – small cracks, corky coating. Looks like a disease but caused by mite. Especially dangerous in hot (about 30 °C) and dry (about 30 % humidity) weather.

Biological control: few specialised predators. Amblyseius fallacis can be used but effectiveness limited.

Natural products:

• Sulfur products – colloidal sulfur (0.3–0.5 %) – one of the few effective means.
• Oil emulsions – at heavy infestation can reduce numbers.
• Pyrethrum – temporarily reduces population.

Agronomy: remove plant debris, rotate crops. In greenhouses, disinfect structures between crops. In regions where mite is a regular problem, choose resistant hybrids.

7. Root‑Knot Nematodes (Meloidogyne spp.)

Appearance: invisible to naked eye. Microscopic roundworms living in soil and attacking roots. Females pear‑shaped, up to 1 mm (Akhatov, 2010; Blancard, 2012).

Signs: swellings (galls) on roots, from small beads to large coalescences. Plants stunted, yellow, wilt in hot weather. Damaged roots cannot supply water and nutrients. Most active at 25–30 °C (Blancard, 2012).

Biological control:

• Nematophagous fungi: Paecilomyces lilacinus, Arthrobotrys oligospora, Pochonia chlamydosporia – their spores penetrate nematode eggs and larvae, killing them. Apply to soil at planting or water with suspension (Dorais & Schwarz, 2018).

• Bacteria Pasteuria penetrans – obligate parasites of nematodes, attach to their surface and cause death. Established in soil through application of infected nematodes.

Trap plants and green manures:

• Marigolds (Tagetes erecta, T. patula): root exudates suppress root‑knot nematodes. Plant in inter‑rows or in rotation (Dorais & Schwarz, 2018).
• White mustard, oil radish (biofumigation): when incorporated into soil, release isothiocyanates toxic to nematodes (Blancard, 2012).

Agronomy:

• Long crop rotation – return tomatoes to infested plot no earlier than 4–5 years. Do not plant after potato, pepper, eggplant, strawberry.
• Organic matter application – increasing soil organic matter promotes nematode antagonists.
• Soil solarisation – in hot climates, cover moist soil with transparent plastic for 4–6 weeks in summer. Temperature under plastic reaches 50–60 °C, killing nematodes and eggs in topsoil (Blancard, 2012).
• Use resistant rootstocks or hybrids – some modern hybrids carry the Mi gene providing resistance to three main species of root‑knot nematodes (Meloidogyne incognita, M. arenaria, M. javanica) (Gavrish, 2005). This resistance holds up to soil temperature 28 °C; above that it may weaken.

Natural products: no specific treatments. Only prevention and soil health improvement.

1. Soil Moisture Retention

Bare soil in hot weather can lose up to 30–50 % of water through evaporation. Mulch creates a barrier that:

• Slows evaporation from the top layer.
• Keeps soil moist longer after watering.
• Reduces watering frequency, especially important in dry regions.

Studies show that mulching tomatoes can reduce water requirement by 25–50 % (Heuvelink, 2018).

2. Protection from Overheating and Cooling

Tomatoes are sensitive to root‑zone temperature. Optimal soil temperature for tomatoes is 20–25 °C (Akhatov, 2010). Bare soil on a sunny day can heat up to 35–40 °C, inhibiting roots and reducing nutrient uptake.

Mulch:

• Reflects or absorbs sunlight, reducing daytime overheating.
• Retains heat at night, protecting roots from sharp temperature swings (Hochmuth & Sideman, 2023).

In cold climates, dark mulch (black plastic, dark compost) additionally warms soil, allowing seedlings to be planted 1–2 weeks earlier (Gavrish, 2005).

3. Weed Suppression

Weeds are the main competitors for water, light, and nutrients. Mulch:

• Physically blocks light needed for weed seed germination.
• Creates a mechanical barrier that weeds cannot penetrate.
• Thickens as organic matter decomposes, smothering small weeds.

In organic farming, where herbicides are prohibited, mulching becomes the main weed control method. Research shows that proper mulching can reduce weeds by 80–95 % (Hochmuth & Sideman, 2023; Dorais & Schwarz, 2018).

4. Preventing Fruit Contact with Soil

Tomato fruits lying on the ground are susceptible to late blight, Alternaria, grey mould, and also become prey for slugs and soil pests (Blancard, 2012). Mulching:

• Creates a clean barrier between fruits and soil.
• Reduces disease infection risk.
• Prevents soil contamination of fruits.

5. Soil Nutrition and Structure Improvement

Organic mulch (grass, straw, compost, leaves) gradually decomposes into humus. During decomposition:

• Nutrients (nitrogen, phosphorus, potassium, micronutrients) are released.
• Soil microflora – bacteria, fungi, earthworms – are activated.
• Soil structure improves – becomes loose, aerated, water‑retentive (Dorais & Schwarz, 2018).

This is a key difference of the organic approach: we do not just "cover" the soil, we feed its living community.

6. Protection from Erosion and Compaction

Raindrops break down the topsoil, creating a crust that prevents water and air penetration. Mulch:

• Softens raindrop impact, preventing crust formation.
• Protects soil from runoff and wind erosion.
• Maintains porosity, allowing roots and organisms to breathe (Hochmuth & Sideman, 2023).

7. Improved Fruit Quality

Research shows that mulching tomatoes leads to higher sugar, vitamin, and dry matter content in fruits. This is related to reduced water stress and more stable root‑zone temperatures (Dorais & Schwarz, 2018). Fruit flavour improves noticeably.

Organic Mulch (Decomposes, Feeds Soil)

Organic mulch is natural material that decomposes over time and becomes fertiliser.

Advantages:

• Excellent moisture retention.
• Easy to apply in thick layers (10–15 cm).
• Decomposes over time, improving soil.
• Light colour does not overheat roots in heat.

Disadvantages:

• May contain weed seeds (better to use winter straw, which decomposes more slowly).
• Can blow away when dry.
• If nitrogen feeding is insufficient, may "draw" nitrogen during decomposition (if C:N > 30:1) (Hochmuth & Sideman, 2023).

When to use: in hot regions, open ground, dry periods. Not recommended on poor soils without additional nitrogen feeding.

Advantages:

• Available, free material.
• Decomposes quickly, feeding soil with nitrogen.
• Good moisture retention.

Disadvantages:

• Fresh grass tends to rot, emits heat, can burn stems.
• Settles quickly, limiting air exchange.
• May contain weed seeds (if grass flowered).
• In rainy periods can promote grey mould.

How to use: always wilt grass for 1–2 days before application. Layer no more than 5–7 cm to avoid rotting. Do not use grass from weeds infested with diseases (Blancard, 2012).

When to use: for feeding and protection during the growing season, but not immediately after rain. Works especially well mixed with straw.

Advantages:

• Excellent material for autumn mulch.
• Over time turns into leaf mould.
• Easily available in forested regions.

Disadvantages:

• Leaves of some trees (walnut, oak) contain tannins that inhibit tomato growth (allelopathy) (Blancard, 2012).
• May contain fungal disease spores (if leaves were diseased).
• Easily blown by wind.

How to use: better to use oak, maple, birch, aspen leaves collected in autumn and slightly decomposed. Do not use walnut leaves (toxic), diseased leaves (infection source).

When to use: in autumn – to protect soil over winter and as organic matter reserve for spring.

Advantages:

• Ideal mulching material – feeds and protects at once.
• Rich in microflora, improves soil health.
• Contains no weed seeds (if well‑composted).
• Does not "draw" nitrogen from soil because C:N is balanced (10–20:1) (Dorais & Schwarz, 2018).

Disadvantages:

• More expensive than other materials (if purchased).
• Takes time to prepare.
• Layer thicker than 3–5 cm may restrict air access to roots.

How to use: layer 3–5 cm around plants, not touching stems. Best to use humus or vermicompost. Plant‑based compost can be used as the main mulch layer.

When to use: throughout the season, from planting to fruiting. Can be applied in autumn under digging.

Advantages:

• Long‑lasting (2–3 years).
• Good moisture retention.
• Suppresses weeds.
• Aesthetically pleasing.

Disadvantages:

• Bark of conifers may acidify soil, not always good for tomatoes (pH 6.0–6.8 needed).
• Fresh bark and fresh sawdust "draw" nitrogen from soil (C:N > 100:1) (Hochmuth & Sideman, 2023).
• May contain bark beetles and other pests.

How to use: only well‑rotted bark or sawdust. Fresh sawdust must be composted or mixed with nitrogenous materials (manure, grass). Layer 5–8 cm. On acidic soils add ash or dolomite lime.

When to use: for long‑term mulch in dry‑climate zones.

Advantages:

• Grow themselves, no application needed.
• Fix nitrogen (legumes).
• Improve soil structure and protect from erosion.
• Shade soil in hot regions.

Disadvantages:

• May compete with tomatoes for water and nutrients if not controlled.
• May attract pests or become disease reservoirs.

How to use: sow low‑growing legumes (white clover, hairy vetch) or grasses (ryegrass, fescue) in inter‑rows. Regularly mow to prevent them outcompeting tomatoes. Leave mown material as additional mulch (Dorais & Schwarz, 2018).

When to use: in regions with long warm seasons, to protect from soil overheating and as an extra organic source.

Advantages:

• Available, free (old newspapers, corrugated cardboard).
• Excellent weed suppression.
• Decompose, enriching soil with cellulose.

Disadvantages:

• Do not provide nutrition.
• Dry out quickly and may crack in dry weather.
• Need weighing down against wind (cover with straw or grass).
• Some newspapers contain toxic inks (avoid glossy paper with bright colours).

How to use: lay cardboard or newspapers (2–3 layers) on moist soil, wet, then cover with 5 cm of straw or grass. Do not use glossy magazines, packaging boxes with adhesive tape.

When to use: early season for weed control and as base for organic mulch.

Synthetic Mulch (Non‑degradable, Long‑lasting)

Synthetic mulches (films, agrotextiles) are widely used in commercial organic farming, especially in greenhouses, but require careful handling.

Advantages:

• Excellent soil warming in spring (2–3 °C above bare soil).
• Completely suppresses weeds.
• Prevents moisture evaporation.
• Prevents fruit contact with soil.

Disadvantages:

• Provides no nutrition – requires separate fertiliser application.
• Does not allow air exchange, may cause root overheating in hot weather.
• End‑of‑season disposal required (plastic).
• May disrupt natural soil microflora cycles.

When to use: in regions with short, cool summers, for early soil warming, in greenhouses with controlled humidity.

Important: lay black film after applying compost and fertilisers so they remain in root zone. Cut planting holes exactly to plant size. In hot regions, may overheat roots – in such cases, use light‑coloured film (white‑black, silver) or organic mulch.

Advantages:

• Reflects sunlight, reducing root overheating.
• Good weed suppression (light side up) or soil warming (dark side up).
• In open ground, reflects light onto lower leaf surfaces, improving photosynthesis and reducing whitefly and aphid numbers (they dislike reflected light) (Akhatov, 2010).

Disadvantages:

• More expensive than black.
• May create excessive reflected radiation, which can be useful in hot climates but may cause fruit burns if incorrectly installed.

When to use: in hot regions, in greenhouses with high insolation, to reduce overheating and whitefly numbers.

Advantages:

• Allows air and water through, does not disrupt gas exchange.
• Protects soil from overheating and drying.
• Completely suppresses weeds.
• Lasts 3–5 years, then degrades or is disposed of.

Disadvantages:

• More expensive than film.
• Weeds may grow through if material is damaged.
• Needs careful anchoring against wind.

When to use: in organic greenhouses and open ground as a long‑term alternative to film.

1. Prepare the Soil

• Thoroughly remove all weeds (especially with roots – dandelion, couch grass, bindweed).
• Apply compost or humus (if not done earlier) and work into topsoil.
• Moisten soil (do not make muddy, just damp).

2. Choose Mulch Material

• For cold climates: black film (for warming) + compost in planting holes.
• For hot climates: straw, hay, light‑coloured film, mown grass.
• For poor soils: compost, humus, green manures (as additional nutrition).
• For humid climates: straw, bark (avoid dense mulch that encourages rot).

3. Apply Mulch

• Organic mulch: layer 5–10 cm (minimum 5 cm for effective weed suppression). Do not place mulch right against the stem – leave a gap 5–10 cm around the stem to avoid overheating the crown and grey mould (Blancard, 2012).
• Film or agrotextile: lay on prepared, moist soil, secure edges, cut planting holes (8–10 cm diameter).
• Paper/cardboard: wet and secure with straw or grass on top (to prevent flying away).

4. Maintain Mulch During the Season

• Organic mulch: refresh as it decomposes (1–2 times per season, especially after rain when it compacts). When mulch starts to break down, it settles – add a thin layer of fresh material on top.
• Film: check integrity, remove weeds that push through holes. At season end, remove and dispose (do not bury).

5. Remove Mulch at End of Season

• Organic mulch: dig into soil (except straw and bark if not decomposed – remove or compost separately).
• Film: collect, clean, and dispose.

1. Choose Location and Container

• Location: shaded, sheltered from wind, but not damp (waterlogging inhibits aerobic bacteria).
• Container: compost bin (wooden, wire mesh), bunker, pit, or simply a pile (bin is more convenient and tidy). Key – good aeration and access to the pile.
• Size: minimum volume 1 m³ (1×1×1 m). Smaller volumes heat less and slow the process (Hochmuth & Sideman, 2023).

2. Correct Material Ratios (C:N)

To launch an effective compost microflora, the correct carbon (C) to nitrogen (N) ratio is needed. Ideal range – 25–35 parts carbon to 1 part nitrogen (by mass) (Hochmuth & Sideman, 2023; Dorais & Schwarz, 2018).

• "Brown" materials (carbon‑rich, C:N 30–100:1): dry leaves, straw, hay, sawdust, wood chips, bark, paper, cardboard.
• "Green" materials (nitrogen‑rich, C:N 10–20:1): fresh grass clippings, kitchen scraps, manure (cattle, horse, poultry), plant tops, nettle, comfrey.

Rule of thumb: for 2–3 parts "green" add 1 part "brown" (by volume, depending on moisture). Too much "green" – compost becomes acidic, foul‑smelling, with high ammonia. Too much "brown" – takes long to mature, poor in nitrogen.

3. Layering

• Place coarse material (twigs, stems) at bottom for drainage and aeration.
• Alternate layers of "green" and "brown" 5–10 cm thick.
• Moisten each layer slightly (moisture like a wrung‑out sponge).
• Add compost activator (a handful of mature compost, vermicompost, or specialised bio‑product) every 2–3 layers to inoculate the pile with microorganisms.
• Repeat until pile reaches 1–1.5 m height.

4. Conditions for Active Decomposition

• Moisture: 50–60 % of field capacity. Squeeze a handful – should release a few drops, not drip (Hochmuth & Sideman, 2023).
• Aeration: turn the pile with a fork every 1–2 weeks (especially first 2–3 weeks). This supplies oxygen to microorganisms and prevents anaerobic rotting. Can also use aeration pipes (perforated plastic pipes inserted into the pile).
• Temperature: inside the pile, temperature should rise to 55–65 °C in the first days (active thermophilic phase). This kills most weed seeds and pathogens. Then temperature gradually falls to 30–40 °C (mesophilic phase), then to ambient (maturation phase).
• Particle size: chop coarse materials (twigs, stems) – speeds decomposition. Ideal size 2–5 cm.

5. Maturation Time

• Fast compost (thermophilic, "hot"): with regular turning and optimal conditions, matures in 1.5–3 months.
• Slow compost ("cold"): without turning, natural decomposition – 6–12 months.
• Mature compost: dark brown, crumbly, smells like fresh forest soil (not putrid). Original materials should be indistinguishable. Temperature stabilised to ambient.

6. Applying Compost to Tomatoes

• In autumn: spread 5–10 kg/m² (3–5 cm layer) over soil surface and dig in to 15–20 cm. Over winter, compost "matures" in soil and becomes available to plants in spring.
• In spring (2–3 weeks before planting): apply 3–5 kg/m² (2–3 cm) and work into 10–15 cm.
• In planting hole: add 1–2 handfuls of compost, mix with soil.
• During the season: use compost as mulch (2–3 cm layer) or as surface dressing (scatter around stems and lightly incorporate).
• Compost tea: steep 1 part compost in 5 parts water for 24–48 h, strain, use for watering (1–2 L per plant) or foliar spray (dilute 1:1 with water).

Compost Tea (Aerobic)

What it is: water extract from mature compost, actively aerated for 24–48 h. Contains living bacteria, fungi, protozoa, and nutrients (Dorais & Schwarz, 2018).

How to prepare:

1. Place 1 part mature compost in a cloth bag (or just in a bucket) and cover with 5–10 parts water (rainwater or settled, chlorine‑free).

2. Aerate using an aquarium pump or manually stir every 2–3 h for 24–48 h.

3. Strain (for spraying) or use with sediment for watering (if you don't mind clogging drippers).

4. Use within a few hours of preparation (while microorganisms are active).

Application:

• Root watering: 1–2 L per plant, 1–2 times a month.
• Foliar spray: dilute 1:1 with water (or use undiluted) and spray in the evening, every 7–14 days.
• Seed soaking before sowing (2–4 h) to inoculate with beneficial microflora.

Effectiveness: compost tea is especially good for preventing fungal diseases (late blight, Cladosporium), as leaf‑surface bacteria compete with pathogens.

Nettle Extract (Fermented, Anaerobic)

What it is: a quick way to get a liquid fertiliser rich in nitrogen, potassium, and micronutrients.

How to prepare:

1. Fill a barrel or bucket with fresh nettle (no roots, preferably before flowering) to 2/3 volume.

2. Cover with water (not to the top, leave 10–15 cm for foam).

3. Cover loosely and leave in a warm place for 1–2 weeks, stirring daily.

4. When fermentation stops (no more foaming), the extract is ready. Strain.

5. Dilute concentrate with water 1:10–1:20 before watering (depending on concentration and plant age).

Application:

• Root watering: 1 L diluted extract per plant, once every 10–14 days.
• Foliar: 1:20, spray in the evening.

Comfrey Extract (Rich in Potassium)

Comfrey (Symphytum officinale) contains high potassium and micronutrients, especially useful during fruit swelling.

How to prepare: similar to nettle extract, but comfrey can be used dry (steeped). Steep 1–2 weeks, dilute 1:10.

Application: root watering during mass fruiting, once every 10–14 days, alternating with nettle extract.

1. Bacteria

Most numerous (up to 10⁹–10¹⁰ cells per gram). Main functions:

• Decompose organic matter (proteins, carbohydrates, cellulose) into mineral elements.
• Fix atmospheric nitrogen (free‑living and symbiotic).
• Produce antibiotics that suppress pathogenic fungi and bacteria.
• Stimulate plant growth through phytohormones and activation of immune systems.
• Participate in nutrient cycling (nitrogen, phosphorus, sulfur) (Dorais & Schwarz, 2018).

Which bacteria are especially beneficial for tomatoes:

• Bacillus subtilis, B. megaterium, B. cereus – produce antibiotics against fungal pathogens (late blight, Alternaria, Fusarium).
• Pseudomonas fluorescens, P. putida – bind iron, making it unavailable to pathogenic fungi, stimulate root growth.
• Azotobacter, Rhizobium, Azospirillum – fix nitrogen (for tomatoes via rhizosphere) (Blancard, 2012; Akhatov, 2010).

2. Fungi

Fungal mycelium penetrates soil for metres, connecting different areas into a network. Main functions:

• Decompose recalcitrant organic matter (lignin, cellulose) – fungi are much more effective than bacteria.
• Form mycorrhiza with tomato roots (Glomus spp., Rhizophagus, Funneliformis) – improve water and phosphorus uptake (by 20–60 %), protect against drought and pathogens (Dorais & Schwarz, 2018).
• Compete with pathogenic fungi (Fusarium, Phytophthora, Rhizoctonia) by secreting antibiotics and physically colonising roots.
• Improve soil structure by gluing particles into aggregates.

Which fungi are especially beneficial for tomatoes:

• Trichoderma (harzianum, viride) – powerful antagonist of soil pathogens (see Chapter 4).
• Mycorrhizal fungi (Glomus mosseae, G. intraradices) – improve phosphorus nutrition and stress tolerance (Dorais & Schwarz, 2018).
• Saprophytic fungi (Penicillium, Aspergillus) – decompose resistant organic residues.

3. Protozoa (amoebae, flagellates, ciliates)

They feed on bacteria and fungi, excreting ammonium (plant‑available nitrogen). They "graze" bacterial populations, maintaining their activity and stimulating organic matter mineralisation. Without protozoa, bacteria quickly consume all available nitrogen and the process slows (Dorais & Schwarz, 2018).

4. Earthworms

The main soil engineers. They:

• Loosen soil to depths of 1–2 m.
• Process organic matter, creating vermicompost – 5–10 times more nutritious than regular compost.
• Improve aeration and water infiltration.
• Stimulate microflora through their mucous secretions and casts (Hochmuth & Sideman, 2023; Dorais & Schwarz, 2018).

Presence of earthworms is a sure sign of living, healthy soil. If few – need organic matter and moderate moisture.

1. Apply Large Amounts of Organic Matter

Organic matter is "food" for microorganisms. Without it they don't live. Use:

• Compost (5–10 kg/m²) – main source.
• Green manures (sow and incorporate).
• Manure (only well‑rotted).
• Leaf litter, mown grass, straw (Hochmuth & Sideman, 2023).

2. Inoculate Beneficial Microorganisms (Bio‑products)

If soil is poor, add ready‑made microbial consortia:

• Trichoderma (powder or suspension) – to suppress fungal diseases and decompose organic matter.
• Bacillus subtilis, Pseudomonas fluorescens – for root protection and growth stimulation (Akhatov, 2010; Blancard, 2012).
• Mycorrhizal fungi – at planting (applied to holes).
• Vermicompost – contains worms, bacteria, and their metabolites.

3. Use Compost Tea

Regular application of (aerobic) compost tea gradually inoculates soil with microorganisms and makes it more alive.

4. Do Not Deep Dig

Deep digging destroys mycorrhizal networks and fungal hyphae, kills worms. Limit to surface loosening (5–10 cm). Apply organic matter to the top layer – microorganisms will distribute it themselves (Dorais & Schwarz, 2018).

5. Mulch

Organic mulch constantly "feeds" soil life, maintaining its activity throughout the season.

6. Observe Crop Rotation

Different plants release different root exudates, which support microbiome diversity. Monoculture depletes certain microbial groups and leads to pathogen accumulation.

7. Use Biofumigant Green Manures (mustard, oil radish)

They simultaneously suppress pathogenic microflora and feed beneficial ones. But do not apply more than once every 2–3 years on the same plot to avoid disturbing the natural balance.