Growing Beets in a Greenhouse: A Complete Guide to Planting and Care

Beetroot is one of the most popular and healthy root vegetables on our tables. It is valued for its excellent taste, dietary properties and rich vitamin and mineral composition. Growing beetroot in a greenhouse allows you not only to get an early harvest, but also to significantly extend the season for consuming this wonderful vegetable, and in some cases - to provide yourself with beetroot all year round. In this article, we will consider in detail all aspects of greenhouse growing of beetroot, from choosing the right variety to harvesting and storing the crop.

Benefits of Growing Beets in a Greenhouse

Greenhouse cultivation of beets has a number of undeniable advantages over cultivation in open ground:

• Early harvest: Sowing in a greenhouse can begin several weeks or even months earlier than in the garden, which allows you to enjoy young beets already at the beginning of summer.
• Extending the fruiting season: In a greenhouse, you can harvest until late autumn, and in heated structures – even in winter.
• Protection from adverse weather conditions: Plants in a greenhouse are protected from spring frosts, hail, strong winds and prolonged rains, which can destroy or significantly weaken plantings in open ground.
• Optimal microclimate: In a greenhouse it is easier to create and maintain ideal conditions of temperature, humidity and lighting for the growth and development of beets.
• Reduced risk of disease and pest damage: The enclosed space of a greenhouse makes it difficult for many pests to enter and for diseases to spread.
• Higher quality of root crops: With proper agricultural technology, greenhouse beets often turn out more tender, juicy, with an even color and without coarse fibers.
• Possibility of multiple harvests: With proper planning and the use of early maturing varieties in a greenhouse, you can harvest two or even three beet crops per season.

Choosing a Beet Variety for a Greenhouse

To successfully grow beets in protected soil, it is important to choose the right variety. Preference should be given to varieties that:

• Early or mid-early: Allows you to get a harvest faster.
• Resistant to bolting: This is especially important for early sowing, when long daylight hours and temperature fluctuations can provoke premature flowering.
• Compact: With a small rosette of leaves, which saves space in the greenhouse.
• Tolerates low light conditions well: Important for early spring and late autumn cultivation.
• They have good taste and shelf life (if storage is planned).

Popular and recommended varieties of beets for greenhouses:

• 'Bordeaux 237': Classic, time-tested mid-season variety (80-110 days). Root crops are round or flat-round, dark red, the flesh is juicy, sweet. Resistant to flowering, stores well.
• 'Detroit': Early ripening variety (80-100 days) of American selection. Root crops are perfectly round, smooth, with thin skin. The flesh is dark red, without rings, tender and sweet.
• 'Pablo F1': A popular early-ripening hybrid (85-95 days). Root crops are even, round, with smooth skin. The flesh is intensely dark red, juicy, sweet, without rings. Resistant to bolting.
• 'Egyptian Flat': Early ripening variety (90-100 days). Roots are flat or flat-round, dark red with a purple tint. The pulp is tender and juicy. Valued for its resistance to drought and heat.
• 'Cylindra': Mid-season variety (100-120 days) with elongated cylindrical root crops. The flesh is dark red, juicy, sweet. Convenient for slicing and processing.
• 'Mulatka': Mid-early variety (95-105 days). Root crops are round, even, with very dark, almost black skin and deep burgundy flesh without rings. Excellent taste.
• 'Nesravlennaya A 463': Mid-season variety (90-110 days). Root crops are flat-round, dark red. The pulp is juicy, tender. Resistant to flowering.

What to look for when choosing seeds?

• Shelf life: Use fresh seeds as germination decreases over time.
• Manufacturer: Give preference to proven seed companies.
• Seed treatment: Some seeds are sold already treated (coated, encrusted), which makes sowing easier and protects seedlings from diseases.

Preparing the greenhouse and soil

The key to a good beet harvest is a properly prepared greenhouse and fertile soil.

When to start preparing?

Preparatory work in the greenhouse should begin 2-4 weeks before the planned date of sowing seeds.

Soil requirements for beets:

Beets prefer loose, well-drained, fertile soils with a neutral or slightly alkaline reaction.

• Soil type: Sandy loam or light loamy soils rich in organic matter are ideal. Heavy clay soils should be improved by adding sand and organic fertilizers.
• Acidity (pH): Optimum pH level is 6.0-7.5. Beets do not tolerate acidic soils (pH below 6.0), the roots grow small, coarse, poorly colored. If necessary, the soil is limed (dolomite flour, slaked lime, wood ash) in the fall or several weeks before sowing.
• Organic substances: Beets are very responsive to the introduction of organic matter. Use well-rotted compost, humus or vermicompost. Fresh manure should not be added to beets! This leads to the formation of ugly, fibrous root crops with poor taste and increased nitrate content.

Stages of soil preparation in a greenhouse:

1. Cleaning and disinfection of the greenhouse: Carefully remove all plant residues from previous crops. Wash the inner surfaces of the greenhouse (glass, polycarbonate, film) with a soap solution or special detergents. Disinfect the structures with a solution of copper sulfate (50-100 g per 10 l of water), bleach (200-400 g per 10 l of water, leave for 2-4 hours) or modern disinfectants.
2. Digging the soil: The digging depth should be at least 25-30 cm (on the bayonet of a shovel), since the beet root goes deep.
3. Fertilizer application (per 1 m²):
   • Organic: 4-6 kg of rotted compost or humus.
   • Minerals:
     • Superphosphate: 30-40 g (or 20-30 g double superphosphate).
     • Potassium sulfate or potassium salt: 20-30 g (or 200-300 g wood ash, which also reduces acidity).
     • Nitrogen fertilizers (for example, ammonium nitrate - 15-20 g, or urea - 10-15 g) are best applied in the spring immediately before sowing or divided into several additional feedings during the initial growth period. Excess nitrogen is harmful to beets.
4. Formation of beds: In a greenhouse, beds are usually made 15-25 cm high and 80-100 cm wide. The distance between the beds (passages) is 40-50 cm for ease of maintenance.
5. Leveling and compacting: Rake the surface of the beds carefully and compact lightly so that the seeds are placed at an even depth.

Optimal conditions in a greenhouse for beets:

• Temperature:
  • Seed germination: Minimum +4-5°C, optimum +18-22°C (shoots appear in 5-7 days). At +10-12°C, shoots will appear in 10-14 days.
  • Growth and development: Optimum daytime temperature +16-22°C, nighttime +10-14°C. Beetroot is a relatively cold-resistant crop, but does not tolerate heat above +25-28°C (growth slows down, root crops become coarser).
• Lighting: Beets are light-loving. They need a full day of light (12-14 hours). In a greenhouse, provide maximum access to sunlight. When sowing in early spring or late autumn, when daylight is short, additional lighting with phytolamps may be required.
• Ventilation: Regular ventilation of the greenhouse is vital for beets. It prevents overheating, reduces excess air humidity (prevention of fungal diseases) and provides an influx of fresh air necessary for photosynthesis.

Sowing beet seeds

When to plant beets in a greenhouse?

The timing of sowing beets in a greenhouse depends on the climatic conditions of the region, the type of greenhouse (heated or not) and the desired time of harvest:

• Early spring sowing (for early summer harvest):
  • In unheated film or polycarbonate greenhouses: end of March – April, as soon as the soil at a depth of 5-10 cm warms up to +6-8°C.
  • In heated greenhouses: you can start sowing as early as February-March.
• Summer sowing (for fall harvest and winter storage): June – early July. Root crops formed in more moderate temperatures and shorter days usually store better.
• Winter sowing (in unheated greenhouses): Late October – November (1-2 weeks before the onset of stable frosts, so that the seeds do not have time to germinate in the fall). Seeds are sown in dry soil to a depth of 3-4 cm and mulched. In the spring, such sowings give a very early harvest.
• Year-round cultivation: Possible in capital heated greenhouses with additional lighting, observing intervals between crops for conveyor production of products.

Preparing beet seeds for sowing:

Beet seeds are multi-fruited fruits, each of which can produce several plants.

• Calibration: Select the largest and most full-weight seeds (fruit sets).
• Germination test: If there is any doubt about the quality of the seeds (especially old ones), carry out a test sowing of a small amount.
• Soaking: To speed up germination, seeds can be soaked in warm water (+20-25°C) for 1-2 days, changing the water every 8-12 hours. You can use a growth stimulator solution (Epin-Extra, Zircon, Potassium Humate) according to the instructions.
• Bubbling: Treating seeds in oxygenated water (for example, using an aquarium compressor) for 12-18 hours also speeds up germination.
• Etching: To prevent fungal diseases, seeds can be treated in a weak solution of potassium permanganate (1 g per 100 ml of water) for 20-30 minutes, then rinsed with clean water. Or use biofungicides (“Fitosporin-M”).
• Germination (optional): After soaking, the seeds can be spread on a damp cloth or gauze until they hatch. It is important not to allow the roots to grow too large.

Beet sowing technique:

1. Cutting furrows: On prepared beds, make furrows 2-3 cm deep (on light soils) or 1.5-2 cm (on heavy soils).
2. Sowing scheme:
   • Distance between rows: 20-30 cm for early ripening varieties with small tops, 30-40 cm for mid- and late ripening varieties.
   • Distance between seeds (fruit sets) in a row: 5-8 cm (with subsequent mandatory thinning).
3. Watering the furrows: Before sowing, water the furrows generously with warm water.
4. Seed placement: Spread the seeds evenly in the furrows.
5. Covering the seeds: Sprinkle the seeds with loose soil, peat or a mixture of soil and humus in a layer of 1.5-2.5 cm. Lightly compact the soil over the seeds.
6. Watering: Water the crops carefully using a watering can fitted with a fine strainer.
7. Mulching (recommended): The surface of the bed can be mulched with a thin layer (1-2 cm) of peat or humus to retain moisture and prevent the formation of a soil crust.
8. Covering (for early sowing): Before the emergence of seedlings, the beds can be covered with agrofibre or film to maintain heat and humidity. After the emergence of seedlings, the cover is removed.

Caring for beets in a greenhouse

High-quality care of beets in a greenhouse includes regular watering, thinning, loosening, weeding, fertilizing and maintaining an optimal microclimate.

1. Watering:

Beetroot is a moisture-loving plant, especially during the period of active leaf growth and root formation.

• Frequency: Water regularly, avoiding both drying out and stagnation of water in the soil. On average, 1-2 times a week, depending on the temperature, air humidity and the phase of plant development.
• Watering rate: The soil should be moistened to the depth of root formation (15-25 cm). Approximately 10-20 liters of water per 1 m².
• Water temperature: Use settled water, warmed to the air temperature in the greenhouse or slightly warmer (+18-22°C). Cold water can cause stress to plants.
• Watering method: It is best to water at the root, avoiding water getting on the leaves, especially in sunny weather, so as not to cause burns. Drip irrigation is ideal.
• Important: 2-3 weeks before harvesting, reduce or stop watering completely - this promotes the accumulation of sugars in the root crops and improves their shelf life. Uneven watering (heavy after a drought) can lead to cracking of the root crops.

2. Thinning:

This is one of the most important operations in growing beets, since several plants often grow from one fruit. Dense plantings lead to the formation of small and deformed root crops.

• First thinning: Conducted in the phase of 1-2 true leaves. Remove the weakest shoots, leaving 2-3 cm between plants in a row.
• Second thinning: 2-3 weeks after the first, when the plants have developed 4-5 true leaves and the root crops have reached a diameter of 1.5-2 cm. The final distance between plants is 6-10 cm (depending on the variety: for varieties with small root crops - less, for large ones - more).
• Technique: It is better to thin out after watering or rain, when the soil is moist. Carefully pull out excess plants, trying not to damage the root system of the remaining ones. Pulled out young beet plants (along with small roots and leaves) can be used for food.

3. Loosening and weeding:

• Loosening: Regularly loosen the soil between the rows and around the plants, especially after watering, to break up the soil crust and improve air access to the roots. Loosening depth is 4-6 cm. The first loosening is carried out a few days after the emergence of seedlings.
• Weeding: Remove weeds promptly, as they compete with beets for light, moisture and nutrients, and can also be breeding grounds for diseases and pests.

4. Top dressing:

When grown on well-fertilized fertile soil, beets can do without frequent fertilizing. However, to obtain the maximum yield of high-quality root crops, it is recommended to carry out 1-2 fertilizing.

• First feeding: 2-3 weeks after germination (or after the first thinning), in the phase of active leaf growth. Mainly nitrogen or complex fertilizers are used.
  • Solution of mullein (1:8-10) or bird droppings (1:12-15).
  • Ammonium nitrate (10-15 g/m²) or urea (8-10 g/m²) dissolved in water.
  • Complex mineral fertilizer (for example, nitroammophoska – 20-30 g/10 l of water).
• Second feeding: In the phase of the beginning of root crop formation (approximately 2-3 weeks after the first, when the root crop reaches the size of a walnut). The emphasis is on phosphorus-potassium fertilizers, which promote root crop growth, accumulation of sugars and improvement of taste.
  • Superphosphate (20-30 g/m²) and potassium sulfate (15-20 g/m²).
  • Wood ash (1-2 cups per 1 m² – scatter and dig into the soil, or in the form of an infusion: 1 cup of ash per 10 liters of water, leave for 1-2 days). Ash is rich in potassium, phosphorus and microelements.
• Boron fertilization: Beets are sensitive to boron deficiency, which can manifest itself as blackening of the core of the root crop (phoma, or dry rot of the core). For prevention, foliar fertilization can be carried out with a solution of boric acid (2 g per 10 l of water) in the phase of 4-6 true leaves.
• Top dressing with table salt (sodium): Some gardeners practice top dressing beets with a weak solution of table salt (1 tablespoon per 10 liters of water) to increase sugar content. This is done 1-2 times per season. However, care should be taken not to cause soil salinization.
• Important: Avoid excess nitrogen fertilizers, especially in the second half of the growing season. This leads to rapid growth of tops to the detriment of the root crop, accumulation of nitrates and deterioration of storage.

5. Maintaining the microclimate in the greenhouse:

• Temperature conditions: Monitor the temperature. On hot sunny days, be sure to ventilate the greenhouse so that the temperature does not rise above +25-28°C. If necessary, you can use shading nets.
• Air humidity: The optimum relative air humidity for beets is 60-75%. Too high humidity (more than 80-85%) promotes the development of fungal diseases. Regular ventilation helps reduce humidity.
• Ventilation: Ensure good air circulation in the greenhouse by opening doors and vents. This is especially important in the morning after a cool night to remove condensation from plants and structures.

Control of beet diseases and pests in a greenhouse

Compliance with agricultural technology and preventive measures help to minimize the risk of beet damage by diseases and pests.

The main pests of beets:

• Beet flea beetle: Small jumping beetles that damage young leaves (they gnaw holes).
  • Control measures: Dusting of seedlings with wood ash, tobacco dust. Treatment with insecticides in case of high numbers (“Aktara”, “Iskra”, “Fitoverm” – strictly according to the instructions).
• Beet fly (miner): The larvae make passages (mines) inside the leaves.
  • Control measures: Deep autumn digging of the soil. Destruction of weeds (especially white goosefoot). In case of severe damage – spraying with insecticides.
• Beet aphid: Sucks the juices from the leaves, causing them to curl and deform.
  • Control measures: Spraying with infusions of tobacco, garlic, soap-ash solution. Attracting ladybugs. Use of insecticides (Biotlin, Aktara).
• Wireworms and false wireworms: Larvae of click beetles and darkling beetles that damage root crops.
  • Control measures: Crop rotation. Liming of acidic soils. Application of ammonia forms of nitrogen fertilizers. Use of traps.
• Slugs and snails: Can damage leaves and roots, especially in wet weather.
  • Control measures: Manual collection. Setting up traps. Using metaldehyde-based preparations (with caution, especially if there are other crops in the greenhouse).

Common beet diseases:

• Rootworm of seedlings: A complex disease caused by soil fungi. Affects sprouts and young shoots, causing them to turn black and die.
  • Control measures: Seed treatment. Use healthy, loose soil. Avoid dense sowing and waterlogging.
• Cercospora leaf spot: Numerous small grayish spots with a reddish-brown border appear on the leaves. If the disease develops strongly, the leaves dry up.
  • Control measures: Crop rotation. Destruction of plant residues. Thinning of plantings for better ventilation. Treatment with copper-based fungicides (Bordeaux mixture, Oxychom) or systemic fungicides (Skor, Topaz).
• Phoma (dry rot of the heart): Appears on leaves as concentric yellowish-brown spots with black dots (fungal pycnidia). Dry rot of the heart develops on root crops. Often associated with boron deficiency.
  • Control measures: Application of boron fertilizers. Crop rotation. Use of healthy seeds.
• Downy mildew (false powdery mildew): Yellowish, blurry spots appear on the upper side of the leaves, and a grayish-purple coating on the lower side. The leaves become deformed and dry out.
  • Control measures: Destruction of plant residues. Thinning. Treatment with fungicides.
• Fusarium root rot: Develops during storage, but infection occurs in the field.
  • Control measures: Crop rotation. Avoidance of mechanical damage to root crops during harvesting. Proper storage conditions.

Preventive measures in the greenhouse:

• Strict adherence to crop rotation (do not plant beets after other amaranths – spinach, Swiss chard – and beets themselves for 3-4 years).
• Use of high-quality, treated seeds of resistant varieties.
• Careful preparation and disinfection of the greenhouse and soil.
• Timely removal of weeds and plant debris.
• Optimal watering and ventilation regime.
• Balanced application of fertilizers.

Harvesting and storing beets

When to remove beets from the greenhouse?

Harvesting times depend on the variety, sowing time and purpose of the product:

• For bunch products (young beets with tops): Harvesting begins when the root crops reach a diameter of 3-5 cm.
• For summer consumption: Root crops are harvested selectively as they ripen, when they reach the typical size and colour for the variety (usually 5-10 cm in diameter).
• For autumn and winter storage: Harvesting is carried out before the onset of stable frosts (usually in September - early October, depending on the region). It is important not to over-keep beets in the garden, as overgrown root crops become coarse, fibrous and are stored worse. Slightly unripe root crops are stored better.

Signs that beets are ready for harvesting:

• Reaching the root crops' characteristic size and shape for the variety.
• The lower leaves begin to turn yellow and wilt (not always an obvious sign in a greenhouse).

How to harvest beets correctly?

1. It is better to clean in dry weather.
2. Carefully dig up the root vegetables with a small shovel or pitchfork, being careful not to damage their skin.
3. Carefully pull the beets out of the ground, holding them by the tops.
4. Clean the root vegetables from any stuck soil (do not wash if you plan to store them for a long time, but let them dry and then carefully brush off the soil with your hands or a soft brush).
5. Cut off the tops with a sharp knife, leaving petioles 1-2 cm long. Do not twist or break off the tops, so as not to damage the neck of the root crop, through which pathogens of rot can penetrate.
6. Discard damaged, diseased, frostbitten or too small root vegetables. It is better to use them first or process them.

Storage of greenhouse beets:

• Short-term storage (up to 1 month): In the refrigerator, in the vegetable compartment, in a plastic bag with holes for ventilation.
• Long term storage:
  • In a cellar or basement: This is the ideal place. Optimal conditions: temperature +1-3°C and relative air humidity 90-95%. Beets can be stored:
    • In boxes or containers, sprinkling layers with dry sand, peat, sawdust or chalk.
    • On shelves in a thin layer.
    • In polyethylene bags (20-30 kg capacity) with small holes for ventilation.
  • On an insulated balcony: In boxes, well protected from light and frost.
• Preparation for storage: Before storing, beets must be thoroughly dried for several days in the shade in a ventilated place.

Potential problems when growing beets in a greenhouse and their solutions

• Bolting (flowering): Premature formation of a flower stalk to the detriment of the root crop.
  • Reasons: Sowing in cold soil, prolonged exposure of seedlings to low temperatures, sudden temperature changes, long daylight hours (for some varieties), drought.
  • Solution: Select varieties resistant to flowering. Maintain optimal sowing dates. Ensure stable temperature conditions and regular watering.
• Cracking of root crops:
  • Causes: Sharp fluctuations in soil moisture (heavy watering after drought). Excess nitrogen fertilizers. Untimely harvesting of overgrown root crops.
  • Solution: Regular and uniform watering. Balanced fertilization. Timely cleaning.
• Woody, coarse or fibrous roots:
  • Causes: Overgrowing. Insufficient or irregular watering, especially in hot weather. High temperature in the greenhouse. Excess nitrogen. Acidic soils.
  • Solution: Timely cleaning. Ensuring sufficient and regular watering. Maintaining optimal temperature. Balanced nutrition. Liming acidic soils.
• Poor color of root crops (pale, with white rings):
  • Causes: Deficiency of certain microelements (e.g. manganese, boron). High temperature. Unsuitable variety. Excess nitrogen. Acidic soils.
  • Solution: Select varieties with intense color. Balanced nutrition, including microelements. Optimize temperature conditions. Control soil acidity.
• Hollowness or voids inside the root crop:
  • Causes: Boron deficiency. Uneven growth due to fluctuations in humidity or temperature.
  • Solution: Add boron fertilizers. Provide stable growing conditions.

Growing beets in a greenhouse with your own hands

Growing beets in a greenhouse is a great way to get an early, abundant and high-quality harvest of this valuable vegetable. Following agricultural recommendations, paying attention to the needs of plants and timely prevention of problems will allow you to enjoy tasty and healthy beets almost all year round. Don't be afraid to experiment with varieties and adapt general recommendations to the conditions of your specific greenhouse, and success will not be long in coming!