Strawberry planting techniques and methods

There are two main types of strawberry cultivation: protected cultivation and open-air cultivation. Protected cultivation is further divided into three types: forced cultivation, semi-forced cultivation, and cold-suppressed cultivation. Let’s learn about the strawberry planting techniques and methods below.

1. Planting time

The best time to grow strawberries in a greenhouse is usually from August to September each year. From late November to March to April of the following year, it is the ripe strawberry picking season. Strawberries grown outdoors are generally planted from March to April each year. The ripening period is from June to July, after which it can be harvested.

2. Site selection

The strawberry planting site should be selected in a place with slightly higher terrain and flat ground. You need to ensure that the land has a good drainage and irrigation system and sufficient sunlight. The soil should be rich in organic matter, have good water retention and air permeability, and a slightly acidic or neutral pH value to ensure fertility. The previous season's crops should be vegetables, beans, melons or wheat, as the planting of these crops helps maintain soil fertility.

3. Land preparation and fertilization

Thoroughly remove weeds from the field to ensure the land is clean. Apply fully decomposed organic fertilizer , about 5,000 kg per mu, and add 50 kg of superphosphate and 50 kg of potassium chloride as base fertilizer. After the fertilizer is evenly spread, tillage to a depth of 30 to 40 cm is performed to promote soil maturation. After the land is leveled, the beds are made at intervals of 100 cm. The bed width is 80 cm, the bed ditch width is 20 cm, the bed height is 15 cm, and the bed length does not exceed 20 meters.

4. Planting

When planting strawberries, pay attention to the orientation of the plants, ensuring that the arch is facing one side of the ditch and the inflorescence grows in the same direction, which will help with subsequent management. Plant one strawberry seedling in each hole. The planting depth should be such that the seedling heart is not buried and the roots are not exposed above the soil surface. Adjust the planting density reasonably according to the growth of strawberry seedlings and soil fertility. Fields with weak seedlings or late plantings should be planted densely, about 8,000 plants per mu; fields with strong seedlings, early plantings, fertile soil or those using mulching technology should be planted sparsely, about 6,000 plants per mu, and the spacing between rows and plants should be controlled at 50 cm × 20 cm.

5. Watering

Water thoroughly immediately after planting to ensure the soil is fully moist. Within one week after planting, water once in the morning and once in the evening to keep the soil continuously moist, which will help the strawberry seedlings survive. After that, water in time according to the soil moisture to keep the soil moderately moist to facilitate the growth of strawberries.

6. Fertilization strategy

Strawberries require a lot of fertilizer from planting to flowering and fruiting. In addition to applying sufficient base fertilizer, it is also necessary to add fertilizer in time during the fruit expansion period and the early stage of harvest. It is recommended to apply 10 kilograms of strawberry-specific fertilizer or diammonium phosphate per mu. When applying fertilizer, combine it with irrigation and apply it in the ditch in the form of 200 times liquid fertilizer, which will be more effective. For fields with vigorous growth, spraying 0.1-0.2% potassium dihydrogen phosphate 2-3 times can also increase yield, but spraying during the flowering period is generally not recommended.

During the fruit picking period, the principle of applying appropriate amounts of nitrogen fertilizers and focusing on phosphorus and potassium fertilizers should be followed, and a reasonable fertilizer ratio should be maintained to achieve high yields and optimal benefits.

7. Mulching

The use of 0.012mm thick black mulch for covering has better weed prevention and heat preservation effects than white mulch, which can significantly promote the early maturity and increase the yield of strawberries, improve the fruit quality, and increase the proportion of commercial fruit. The schedule for ground film covering is: cover with black ground film from October 25 to 30, cover with greenhouse film around November 5, and cover with inner ring greenhouse film as needed from late November to early December to prevent frost damage.

8. Closing time

When the outside night temperature drops to 8-10℃, the shed should be covered in time for insulation. If insulation starts too early, the temperature in the greenhouse will be too high, which will affect the differentiation of strawberry flower buds; if insulation starts too late, it may cause the plants to enter a dormant state, and growth and fruiting will be hindered. Generally speaking, temperatures below 5°C will cause strawberries to enter a dormant state, and 6-7°C at night is the critical temperature for heat preservation.

9. Temperature regulation

The temperature in the greenhouse is mainly regulated through air vents. After covering the greenhouse, after 10 am on a sunny day, if the temperature in the greenhouse rises to above 35℃, the greenhouse film should be opened for ventilation and cooling, and the temperature in the greenhouse should be kept at 28-30℃ during the day and 12-15℃ at night, and the lowest should not be lower than 8℃. As the outside temperature continues to drop, straw thatch should be covered on the greenhouse film at night to enhance the insulation effect. When the temperature in the greenhouse drops to 8-10℃ at night, you should start to remove the straw thatch in the morning and evening to regulate the temperature in the greenhouse. When adjusting the temperature in the greenhouse during the day, you can do so by removing the straw cover, adjusting the size of the vents and the ventilation time.

10. Humidity Control

The humidity in the greenhouse mainly comes from the evaporation of soil and plants. Using mulch to fully cover the soil can effectively reduce the humidity in the greenhouse, and combining it with drip irrigation technology can further reduce the humidity. Reducing humidity requires consideration of many factors. Often, there is a conflict between humidity control and heat preservation, especially in the morning when humidity is highest and the need for heat preservation is most urgent. Around noon is the best time to ventilate, cool down and reduce humidity. At other times, you should focus on keeping warm and pay attention to humidity regulation.

11. Fertilizer and water management

After covering the greenhouse, the temperature inside the greenhouse rises, water evaporation accelerates, and the soil is prone to water shortage. Therefore, adequate water supply must be ensured to promote vigorous growth of the plants. In the early stage of flowering, combined with topdressing (through trenching or hole application), water should be poured thoroughly once. In mid-November, depending on the growth of the plants, apply 1-2 times of large amounts of water-soluble fertilizer , about 4 kg per mu, to promote fruit enlargement. In the later stage of harvesting, appropriate additional fertilizer should be applied according to the growth of the plants after each harvest.

12. Ventilation

Starting from February, high temperatures may occur in the greenhouse (over 35°C may affect the growth of strawberries), and ventilation is required in a timely manner. Close the greenhouse film in time before sunset to maintain the temperature and reduce the occurrence of powdery mildew and gray mold.

13. Flowering period management

Strawberry buds begin to form about 30 days after the greenhouse is covered. The suitable temperature during the budding period is 25-28℃ during the day and 10℃ at night. Management during the flowering period is particularly critical, and temperature and humidity regulation need to be done well. During the flowering period, the temperature in the greenhouse should be controlled at 23-25℃ during the day and 8-10℃ at night. The minimum temperature for strawberry flowers to bloom is 11.7℃, and the suitable temperature range is 13.8-20.6℃. Too low temperature will affect anther dehiscence, thus affecting pollination and fertilization. The humidity in the greenhouse should not be too high during the flowering period, and the relative humidity should be controlled at around 40%. Flower thinning should be carried out in a timely manner to remove high-order, small and weak flowers, retaining 7-10 healthy flowers. As the fruit setting progresses, deformed, diseased and small fruits should be removed, ultimately retaining 3-5 fruits in each inflorescence.

14. Assisted pollination and plant management

Although strawberries can self-pollinate and produce fruit, environmental conditions in greenhouses may not be conducive to pollination and fertilization. When entering the initial flowering period, bees should be placed to assist in pollination, which can not only improve fruit quality and increase yield, but also reduce the occurrence of deformed fruits. When strawberries are in bloom, the plant's side buds begin to grow. Old leaves and excess side buds need to be removed in time. In principle, in addition to the main bud, no more than 2-3 side buds should be retained to maintain healthy growth of the plant.

15. Characteristics of maturity

It usually takes about 50 days for strawberries to grow from flowering to maturity in a solar greenhouse, but this time is significantly affected by temperature. At lower temperatures, the fruit takes longer to ripen, up to 60 days. Under solar greenhouse conditions, even at optimal temperatures, it takes at least 40 days for strawberries to mature. The surface of ripe strawberry fruit turns red and is accompanied by a unique strawberry aroma, which is the main sign of its maturity.

16. Post-harvest management

After harvesting the fruits of the first strawberry inflorescence, the field should be cleaned immediately to remove diseased leaves, old leaves and remaining inflorescence stalks. At this time, the second inflorescence begins to form, and flower and fruit management is still important. It is recommended to retain 3 to 5 fruits in each inflorescence. Since this period coincides with the low temperature season, fruit setting is greatly affected by temperature, so fruit thinning should be the main focus, removing deformed and diseased fruits.

As the fruits of the second inflorescence begin to mature at the end of December, the third inflorescence also begins to bloom and set fruit. At this time, late management should be carried out according to temperature changes, with an emphasis on fertilizer and water management. As the temperature rises, the evaporation of water from plants and soil increases. At this time, a large amount of water-soluble fertilizer should be applied in combination with irrigation, with a dosage of about 4 kg per mu, and fertilization should be carried out through a drip irrigation system.

In early March, as the temperature continues to rise, the vents should be enlarged and the ventilation time extended to keep the room temperature at about 25°C during the day and about 8°C at night. Too high a temperature will cause the fruit to become smaller and have reduced quality. When the night temperature in the shed remains above 5°C, ventilation and heat release should be stopped. After late March, the inner film should be removed in time to lower the temperature in the greenhouse.

In late May, we began to remove the greenhouse film and renovate the greenhouse in preparation for next year's planting. The greenhouse strawberry harvest usually lasts until the end of May.

In summary, through these meticulous management measures, we can ensure the healthy growth of strawberries, improve fruit quality, extend the harvest period, and prepare for the next season's planting.