Physiological disorders

How to Recognise Boron Starvation?

Symptoms appear on both leaves and roots. Knowing these signs will help you spot the problem before the root becomes unfit for storage.

On leaves (first signs):

• Young leaves in the centre of the rosette stop growing, become small, pale, curled, or boat‑shaped.
• Leaf stalks become brittle and may develop cracks and spots (Nonnecke, 1989).
• Leaves take on a mottled colour – alternating yellow and purple patches. The terminal bud may die, which stops plant growth.

On the root (most important for the gardener):

• When you cut the root, in the central part (often in the upper third) you see dark‑brown, almost black, dry or corky spots of irregular shape.
• These areas may be hard and cork‑like; with severe deficiency they turn into hollows.
• Transverse cracks may appear on the root surface, especially near the crown.
• The root often becomes misshapen, with rough, scabby skin (Rana, 2018).

It’s important to distinguish this from ordinary "woodiness" (which we’ll discuss later). In boron starvation, the damage comes from the inside, not from the surface.

Why Does Boron Deficiency Occur?

Boron is relatively immobile in the soil. Plant roots take it up only from the soil solution. Its availability depends heavily on conditions:

1. Dry weather. Boron dissolves poorly in dry soil, and roots can’t "drink" it. That’s why the problem often appears in drought years or in unirrigated areas (Kemble, 2022).

2. Light sandy and sandy‑loam soils. On such soils, boron is easily leached from the root zone.

3. High soil pH (alkaline conditions). At pH above 6.5–7.0, boron becomes unavailable to plants. The problem is especially common after liming.

4. Excess nitrogen and potassium. Applying large doses of nitrogen or potassium fertilisers worsens boron deficiency by upsetting the nutrient balance.

5. Incorrect organic matter application. Fresh manure or too much organic fertiliser can bind boron.

What to Do? Prevention and Control Measures

Boron starvation is easier to prevent than to cure. Here’s a proven strategy that works for both amateurs and farmers (Torikov, Sychev, 2018):

1. Soil analysis. The best thing you can do is have your soil tested in advance. This will let you determine the exact boron rate. But even without a test, on light soils and in high‑risk areas, it’s worth applying boron preventively.

2. Soil application of boron (base fertiliser).

• In spring, before sowing or planting transplants, apply borax (Na₂B₄O₇·10H₂O) or boric acid.
• For home gardeners, a rough rate is 1–2 grams of boric acid (or 1.5–3 grams of borax) per 1 square metre of bed. Scatter evenly and work into the topsoil.
• Don’t exceed the rate! Boron is a micronutrient – too much is toxic.

3. Foliar feeding (the most reliable method for gardeners).

• During active root growth (4–6 true‑leaf stage), spray the plants with a boric acid solution.
• Solution: 1 gram of boric acid per 1 litre of water (i.e., 0.1% solution). For larger volumes: 10 g per 10 L of water.
• Spray on a cloudy day or in the evening so the solution doesn’t dry out too quickly and has time to be absorbed.
• Repeat the spray after 2–3 weeks if deficiency signs persist. Usually one or two treatments per season are enough.

4. Proper watering. Boron is taken up only from moist soil. During dry spells, ensure regular watering of beetroot. Sharp moisture fluctuations also encourage deficiency.

5. pH control. If you’ve limed the soil, be sure to replenish boron, because at high pH it becomes less available.

Remember: treating boron starvation at a late stage, when internal damage has already formed, is impossible. Affected roots won’t recover, but you can still eat them by cutting out the dark parts (they aren’t poisonous). The main goal is to prevent the problem in the next season.

Now that we’ve dealt with the "queen" of physiological disorders – boron starvation – let’s move on to the next common but less well‑known problem. It doesn’t ruin the taste, but it seriously hits the appearance and marketability of the root. We’ll talk about zoning (ringing) of the flesh. What is it, why does it happen, and can it be prevented?

---

What Does It Look Like?

On the cut of the root, you clearly see alternating rings (circles) of darker and lighter colour. Sometimes they can be so contrasty that they resemble a target. The taste of the root may remain normal, though in some cases it may be less sweet or coarser (Torikov, Sychev, 2018).

Why Do Rings Appear?

The main cause is an imbalance between the supply of water and nutrients during root growth. The flesh of beetroot consists of alternating tissue layers: some store sugar and pigments, others conduct water and nutrients (Goldman, 2020). Under ideal conditions, these layers develop evenly and colour to one deep shade.

As soon as conditions change, the process is disrupted:

1. Heat (the most common culprit). At high temperatures (above 25–30 °C), the synthesis of the red pigment (betacyanin) is suppressed. During hot periods, paler layers form. When the heat subsides, darker layers form – hence the "rings" (Rana, 2018).

2. Uneven moisture. If drought periods are followed by heavy watering, root growth becomes jerky. Rapid growth "on the wave" of moisture gives pale, blurred layers, while slow growth gives darker, denser ones.

3. Fast growth overall. Young, vigorously growing roots often have less intense colour and more visible rings than mature ones that grow more slowly. This is especially noticeable in early varieties.

4. Varietal characteristics. Some beet varieties are genetically more prone to zoning than others. As a rule, varieties with intense, dark‑red flesh (e.g., `Bordeaux 237`) show less zoning than those with lighter flesh (Nonnecke, 1989; Kemble, 2022).

5. Potassium deficiency or nitrogen excess. An imbalance of these elements can also affect tissue colour.

Consequences for the Gardener

Zoning is primarily a cosmetic defect. It doesn’t affect the nutritional value of the root (except for a possible reduction in sugar content in the pale layers). However, for those growing beet for sale, it’s a serious problem: customers buy with their eyes, and a blotchy root may not sell. For home use, it’s just an annoying flaw you’d like to avoid.

How to Prevent Zoning?

Knowing the causes, we can manage conditions to minimise contrast rings.

1. Steady watering. This is the golden rule. Try to keep the soil moderately moist, without sharp fluctuations. Regular, not too heavy watering in hot weather is the best prevention.

2. Mulching. A layer of mulch (straw, mown grass, compost) helps retain soil moisture, prevents drying out, and protects roots from overheating.

3. Timely sowing. To avoid the peak of heat coinciding with the active root‑growth period, in southern regions it’s better to sow beet early in spring or before winter. In temperate zones, try to ensure that hot July–August doesn’t catch your roots in the rapid‑growth stage.

4. Variety selection. If you often face this problem, choose varieties and hybrids with high pigment content that are resistant to zoning. This is usually indicated in the variety description.

5. Balanced nutrition. Apply compound fertilisers; don’t over‑feed beet with nitrogen alone. Potassium and micronutrients help nutrient uptake and improve colour.

Zoning is a signal from the plant: "I was hot and dry." Respond correctly, and next year the cross‑section will delight you with an evenly deep, rich colour.

We’ve looked at the "colour" of beet. But there’s another "appearance" problem that suffers just as much – cracks on the root. That’s the next item on our list. Why does beet crack, and how do you deal with it? Let’s talk about that in the next chapter.

---

What Does It Look Like?

Cracks can be of different types:

• Transverse ring cracks – go around the circumference of the root, mostly in the upper part, near the crown.
• Longitudinal cracks – splits along the root, sometimes very deep.

Whatever the type, the essence is the same: the skin (periderm) can’t withstand internal pressure and tears (Nonnecke, 1989).

Why Does Beet Crack? The Main Cause – Sharp Moisture Fluctuations

Imagine the root as a balloon. When it grows slowly and evenly, its walls (the skin) manage to adapt to the increasing volume. But if, after a long drought, a heavy rain suddenly falls or you give a generous watering, the plant greedily absorbs moisture. The flesh cells swell rapidly, the root quickly increases in size, and the skin – which became rougher and less elastic during the drought – simply can’t stretch in time. The result – a rupture (Goldman, 2020; Kemble, 2022).

This is the most common and main mechanism of cracking. But there are other factors that make it worse:

1. Uneven watering. "Dry‑wet" swings always provoke cracks. Especially dangerous is heavy watering after a prolonged drought.

2. Sharp temperature changes. Alternating very hot and cool weather also causes stress and uneven growth.

3. Excess nitrogen fertilisers. Nitrogen stimulates rapid, "watery" cell growth, which increases pressure on the skin and makes it more prone to tears.

4. Over‑maturity. If you leave beet in the ground too long, it becomes large, the flesh gets coarser, and the skin loses elasticity. Such roots crack more often.

5. Varietal features. Some varieties are more prone to cracking than others. These are usually varieties with thin skin or those that put on weight quickly.

How to Prevent Cracking?

Knowing the main cause, we can build a protection strategy:

1. Regular and moderate watering. This is the main rule. Water beet evenly, avoiding both drying out and waterlogging. It’s especially important to maintain stable moisture during active root growth. In hot weather, water more often but in small amounts.

2. Mulching. A layer of mulch (straw, mown grass, compost) helps retain soil moisture, prevents crust formation, and smooths out moisture fluctuations. This is your best ally in fighting cracks.

3. Avoid sudden watering after drought. If beet hasn’t received water for a long time, don’t create a "flood." Start with light moistening, and after 1–2 days do a full watering. This allows the skin to gradually adapt to the increased volume.

4. Harvest time. Don’t keep beet in the ground too long, especially in wet weather. Over‑grown roots are more prone to cracking.

5. Balanced nutrition. Don’t over‑feed beet with nitrogen. Prefer compound fertilisers with an emphasis on potassium and phosphorus, which make tissues denser and more resilient.

6. Choose resistant varieties. If cracking is a regular problem, select varieties that are resistant to this defect. Usually these are varieties with dense flesh and strong skin (e.g., `Bordeaux 237`, `Cylindra`).

Cracking is a signal that you’re changing the watering regime too abruptly. Take it seriously, and your beet will reward you with smooth, even sides.

We’ve covered the most visible problem – cracks. But there are other "internal" defects that aren’t as obvious but are just as important. For example, when the flesh becomes coarse, fibrous, or wood‑like. Or when hollows form inside the root. And then there are all sorts of deformations: forked, twisted, flattened roots. All of these are in the following chapters.

---

What Does It Look and Feel Like?

When cut, such a root looks "dry" with clearly visible fibrous bundles. The taste may be bitter or bland. The flesh doesn’t melt in the mouth but requires thorough chewing. This is not a disease but a physiological condition often confused with boron starvation (but in boron deficiency the damage comes from inside, while here the whole flesh is coarse).

Why Does the Flesh Become Coarse and Fibrous?

Think of beet, like any vegetable, as having a "shelf life" in the ground. With age, cell walls thicken, and tissues undergo lignification (woodiness). This is a natural ageing process, but it can be greatly accelerated by stress.

Here are the main causes (Nonnecke, 1989; Torikov, Sychev, 2018):

1. Ageing and over‑maturity (the most common cause). If you leave beet in the ground too long, especially in hot or dry weather, it begins to "age." Cells lose water, walls thicken, and the root becomes tough. This is a natural process: the plant prepares for dormancy, and its tissues become coarser and denser.

2. Drought and lack of moisture. When beet experiences water stress, its growth slows down. Substances that make tissues harder accumulate. This is a protective response that helps the plant survive dry conditions.

3. Excess nitrogen fertilisers. Paradoxically, nitrogen is needed for growth, but its excess causes cells to grow too fast, become watery, and then – when growth slows – these "watery" tissues quickly turn coarse. Moreover, excess nitrogen reduces sugar content, making the flesh less juicy.

4. High temperature. Heat, especially combined with dryness, accelerates tissue ageing, making them coarse and fibrous.

5. Potassium deficiency. Potassium plays a key role in carbohydrate synthesis and maintaining cell turgor. When it’s lacking, tissues become loose and then coarsen quickly (Kemble, 2022).

6. Late harvest. The longer beet stays in the ground, the more it ages. Even if it hasn’t over‑grown, autumn cooling and preparation for winter dormancy trigger tissue coarsening.

Consequences for the Gardener

The main problem is loss of taste and marketability. Tough beet is hard to peel and cut, and it doesn’t cook well. It’s unsuitable for long storage (flavour deteriorates quickly). Moreover, coarse flesh is not just unpleasant – it’s also a sign that the root has lost nutritional value.

How to Grow Tender and Juicy Beet?

To avoid "woodiness," you need to help the plant grow evenly and not age prematurely.

1. Observe harvest dates. This is the most important rule. Don’t leave beet in the ground too long. Harvest when it reaches the typical size for the variety (usually 5–10 cm in diameter). Follow the maturity dates on the seed packet.

2. Regular watering. As with zoning and cracking, steady moisture prevents stress and tissue coarsening.

3. Balanced nutrition. Don’t over‑feed with nitrogen. Use compound fertilisers with a predominance of potassium and phosphorus. Potassium makes tissues supple and juicy, while phosphorus supports root development.

4. Timely thinning. Dense sowings cause stress. Plants compete for light, water, and nutrients, leading to slower growth and premature ageing of tissues.

5. Choose varieties with tender flesh. Some beet varieties are naturally more juicy and tender. Look for types like `Nantes` (for carrots) or `Detroit` (for beet) – they generally have a finer texture.

Coarseness is a signal that the plant was uncomfortable. By adjusting your care, you’ll get juicy, tender, sweet beet that’s a pleasure to eat and cook.

We’ve covered three "external" problems. But there’s another, very unpleasant one – when hollows appear inside an otherwise healthy‑looking root. That’s the next chapter.

---

What Does It Look Like?

On the cut, you see irregularly shaped hollows (cavities). They may be single or multiple, located in the centre or closer to the surface. The walls of the cavities are often dry, corky, and may have a brownish tint. The taste and texture of the flesh around the hollows are usually normal, but the cavity itself makes the root unsuitable for slicing, grating, or long storage.

Why Do Hollows Form?

This results from an imbalance between the growth of tissues. Imagine that the inner tissues of the root grow faster than the outer ones. When internal pressure becomes too high, tissues tear, forming cavities (Goldman, 2020). Several factors worsen this process:

1. Boron starvation (the main cause). Yes, we’re back to boron. Boron deficiency disrupts cell division and vascular system formation. As a result, individual tissue areas die off and are replaced by hollows. This is one manifestation of boron deficiency, but not the only one. Unlike heart rot, which produces dark, dense spots, here we get actual cavities (Rana, 2018; Nonnecke, 1989).

2. Rapid growth. When beet grows too fast (e.g., after heavy rains or watering combined with high temperatures), inner tissues may "outpace" outer ones. Cells grow unevenly, and where connections between tissues break, cavities form.

3. Sharp moisture fluctuations. A familiar problem! Drought followed by heavy watering – the root starts to gain mass rapidly, and the inner tissues, which "stalled" during the dry period, can’t withstand the pressure and tear, forming hollows.

4. Potassium deficiency. Potassium regulates water balance and cell‑wall elasticity. When lacking, tissues become loose and less elastic, increasing the risk of hollows.

5. Varietal characteristics. Some beet varieties are more prone to hollow formation than others. Usually these are large‑fruited varieties with loose flesh.

6. Ageing. Over‑mature beet, whose tissues are ageing and losing turgor, can also develop hollows.

Why Are Hollows Dangerous?

The main problem is loss of market quality. A root with hollows can’t be cut nicely; it spoils quickly in storage because moisture accumulates in the cavities and rot develops. The taste may be normal, but its use is limited (only for boiling or processing).

How to Prevent Hollow Formation?

Prevention of hollows largely overlaps with prevention of other disorders.

1. Boron is everything! Apply boron to the soil (borax or boric acid) before sowing, or do foliar sprays during active growth. This is your main weapon against hollows.

2. Steady watering. Avoid sharp moisture fluctuations. Water regularly but moderately, especially in hot weather. Mulching helps keep moisture and smooth out variations.

3. Balanced nutrition. Don’t over‑feed with nitrogen. Use compound fertilisers with potassium and phosphorus. Potassium is especially important for tissue firmness.

4. Timely harvest. Don’t leave beet in the ground too long. Harvest when it reaches the optimal size for the variety.

5. Choose resistant varieties. If hollows recur year after year, try varieties with dense, uniform flesh (e.g., `Bordeaux 237`, `Detroit`, `Cylindra`). They are generally less prone to hollow formation.

Hollows inside beet are a signal that the plant experienced stress related to nutrition and moisture. If you adjust your care approach, the chances of getting dense, hollow‑free roots increase significantly.

We’ve dealt with what happens inside the root. But there’s another group of problems concerning the shape of the beet. It may not be round or smooth but forked, twisted, or flattened. This isn’t just cosmetic – it’s a consequence of stress and growing mistakes. Deformed roots are up next.

---

What Does It Look Like?

Deformations can be many, but the most common types (Nonnecke, 1989) are:

1. Forking (splitting). The main root divides into two or more "horns." This is the most frequent and most annoying deformation.

2. Flattening. The root becomes flat like a pancake instead of round or cylindrical.

3. Bending. The root grows not straight but curved, taking on a bizarre shape.

4. Short or thickened roots. They don’t reach the variety’s typical length, becoming "stocky."

Why Does Beet Deform?

The beetroot is a greatly swollen main root and hypocotyl (part of the stem). Any damage or obstacle in the path of this growing root causes it to branch or curve. Remember: to grow a straight root, you need to let it grow freely both in depth and width.

Here are the main causes of deformations:

1. Mechanical obstacles (the main cause). These can be:

• Stones, clods of earth, compacted soil layers. The growing root hits an obstacle and begins to branch or bend to get around it (Nonnecke, 1989; Torikov, Sychev, 2018).
• Unbroken lumps of manure or plant residues. They create the same problems.
• Hardpan or plough pan. If there’s a compacted layer below the topsoil, the root can’t penetrate deeper and starts growing sideways.

2. Damage to the main root. This can happen from:

• Transplanting seedlings. If you grow beet through transplants and damage the main root, it branches (Torikov, Sychev, 2018).
• Deep hoeing or weeding. Accidental cutting of the root produces the same result.
• Pest damage. Nematodes or soil pest larvae can damage the root tip, triggering branching.

3. Too loose or too dense soil. In very loose soil, the root may grow too fast and lose shape. In heavy, clayey soil, it struggles to penetrate deeply and becomes short, thickened, and often bent (Kemble, 2022).

4. Uneven plant spacing. If beet is planted too densely, plants compete for space. Roots may deform as they try to find free room.

5. Excess nitrogen or fresh manure. This stimulates lush top growth but may disrupt root formation, making it loose and prone to deformities.

6. Acidic soil (low pH). In acid soils, root development is poor, which can also cause deformities.

How to Grow Even and Beautiful Beet?

Preventing deformations starts with bed preparation and proper care.

1. Thorough soil preparation. This is the most important rule.

• Deep digging. Dig the bed to a spade’s depth (25–30 cm), carefully removing all stones, weed roots, and large clods. The soil should be loose, uniform, and fine‑crumbly (Nonnecke, 1989).
• Avoid fresh manure. Use well‑rotted compost or manure, not fresh.
• Improve structure. On heavy clay soils, add sand and organic matter to improve drainage and looseness.

2. Direct sowing in the ground. Beet does not tolerate transplanting with root damage well. It’s best to sow it directly in its permanent place. If you do use transplants, transplant very carefully with a ball of soil, trying not to damage the root (Torikov, Sychev, 2018).

3. Optimal planting pattern. Don’t crowd the plants. Follow the recommended spacing (usually 5–10 cm between plants in the row and 30–45 cm between rows). Crowding leads to competition and root deformation.

4. Regular watering. Keep the soil moderately moist. As with other disorders, sharp moisture swings are harmful.

5. Balanced nutrition. Apply compound fertilisers, avoiding a bias toward nitrogen. Potassium and phosphorus are important for forming a dense, even root.

6. pH control. Maintain a neutral or slightly acidic reaction (pH 6.0–7.0). If needed, add dolomite lime or wood ash.

7. Thinning. Thin seedlings at the 2–3 true‑leaf stage, leaving the strongest plants at the right distance.

Deformations are almost always the result of poor soil preparation or root damage. Give these issues your attention, and your beet will reward you with even, beautiful, large roots.

With this, we complete our overview of the main physiological disorders in table beet. You’ve learned how to tell them from diseases, how to recognise each disorder, and – most importantly – how to prevent them with simple, accessible agronomic practices.

Remember: healthy beet is the result of balanced care – the right variety choice, proper soil preparation, smart watering, and timely fertilisation. I hope this knowledge helps you achieve excellent harvests!