Detailed Guide to Strawberry Cultivation: These 5 Reasons May Be Why the Fruit Isn't Sweet

Strawberries are a common fruit, with a sweet-and-sour taste and rich nutrition, deeply loved by consumers, and cultivated in every region of our country. Generally speaking, strawberries are sweet once ripe, but many growers produce strawberries that aren't sweet, which affects economic returns and causes great distress. So how do you grow strawberries? And what causes them not to be sweet?

I. How do you grow strawberries?

1. Preparation of the propagation seedling bed

(1) Choose paddy fields that drain and irrigate easily, are not prone to waterlogging, and have relatively high fertility, or vegetable garden soil (the previous crop and soil blocks where chlorsulfuron herbicide has been used). Apply sufficient base fertilizer (cake fertilizer, farmyard manure, human excrement and urine, phosphate fertilizer), spread it after it has decomposed, and at the same time apply 1 jin of 50% phoxim or 3 jin of 3% carbofuran per mu, mix with 25 jin of fine soil, spread it, then plow the soil and make beds. The beds should be 1.5-1.8 m wide, shaped like a turtle shell to prevent waterlogging, and the soil should be fine and crumbly.

(2) Selection of each plant and planting. Choose plants with new leaves unfolding normally, symmetrical leaflets, dark green leaf color, thick petioles, large leaves, vigorous growth, and good yielding ability; remove diseased leaves and old leaves. In our city, planting in the propagation field is generally done in April of the Gregorian calendar (daily average temperature above 12°C). Plant two rows per bed, setting plants 30 cm from the edge of the bed surface, with a plant spacing of 60-80 cm. After planting, water immediately to settle the roots.

(3) Fertilizer and water management. The principle of fertilizing the seedling bed is: moderate nitrogen, heavy phosphorus and potassium. Per mu, use 200 jin of decomposed rapeseed cake plus 7-8 jin of urea, 50 jin of phosphate fertilizer, and 10 jin of potassium fertilizer, dissolve in water, and irrigate once every 20 days. Human excrement and urine can also be used as a substitute.

(4) After each plant has survived planting (one week later), spray gibberellin (920). That is, dilute each gram of "920" in 40-50 jin of water ("920" should first be dissolved in high-concentration white liquor in a clean bowl) and spray. Spray twice in succession, with an interval of one week to 10 days. In August, strictly control nitrogen fertilizer application and let the plants dry out appropriately, but not excessively.

2. Timely transplanting and preparation and specifications of the transplanting field

(1) Field preparation: Choose fertile fields or soil with convenient drainage and irrigation as the field site. Strawberries have a relatively high fertilizer requirement, and since later stages (fruit-picking period) generally involve less fertilization, the base fertilizer must be sufficient, mainly organic fertilizer. Generally, per mu: 1500 kg of organic fertilizer, 50 kg of cake fertilizer, 25-30 kg of compound fertilizer, 7.5 kg of urea, 40 kg of calcium superphosphate, and 10 kg of potassium fertilizer. Except for urea and compound fertilizer, mix the other fertilizers evenly, let them decompose, then mix evenly with urea and compound fertilizer, spread on the soil surface, and then plow the soil and make ridges. Generally, ridge height is 25-30 cm, ridge bottom width 90 cm, ridge surface 60 cm. The furrow width is 30 cm, and the ridge bottom plus furrow width is about 100-120 cm, with a certain slope from the ridge surface to the furrow bottom.

(2) Planting period and method: In our city, protected cultivation is generally transplanted from late September to early October. Planting density should be treated according to seedling condition and whether the land is fertile or poor; strong seedlings, dryland seedlings, and fertile land are suitable for sparser planting. Otherwise, denser planting is suitable. Generally, 7,000-9,000 plants per mu. After the ridges are made, plant 5 cm inward from the ridge edge, with a plant spacing of 12-15 cm. Ridge length generally should not exceed 30 m.

(3) When transplanting, note the following: First, oriented transplanting: with the curved back facing outward, which helps the inflorescence emerge later. Second, plant in a double-row triangular (pinwheel) arrangement, which helps ventilation, light penetration, and rooting. Third, grasp the depth correctly, so that roots are not exposed below and the seedling heart is not buried above, which helps tillering. Fourth, transplant with soil, which helps survival. Fifth, plant on sunny afternoons, or all day on cloudy days. Sixth, strengthen water and fertilizer management; after planting, immediately water thoroughly to settle the roots, and when watering, add thiophanate-methyl at 800 times dilution. Seventh, promptly check for missing seedlings and fill gaps.

3. Field management

(1) Pre-winter management: from surviving planting to mid-to-late November, pay attention to three points: first, apply thin fertilizer frequently, mainly nitrogen fertilizer, preferably dilute manure water; second, keep the soil moist; third, weed, loosen the soil, and remove old leaves and diseased leaves.

(2) Management before and after flowering: before flowering, at the young fruit stage, and at the fruit enlargement stage, promptly spray Caiguo Zhuangdiling to increase the strawberry's cyclic fruit-setting rate and promote fruit development, while using thiophanate-methyl, procymidone, dimethoate, and the like to control pests and diseases.

(3) Overwintering management: before the severe cold arrives, water thoroughly to prevent cold damage.

4. Timely film covering

Covering with film can multiply yield and reduce fruit loss and prevent contamination. Film is divided into greenhouse film and plastic mulch. The timing of film covering should be when the daily average temperature drops to about 8°C. Cover the greenhouse film first, then the plastic mulch. Before covering, first weed, cultivate, fertilize, and control pests and diseases. (The production of the greenhouse and the model of film to purchase) Due to limited space, these will not be introduced; those interested please contact the Agricultural Science Institute. After covering, the temperature inside the greenhouse at night should be maintained at 8°C, and around 20°C during the day; on sunny days at noon, the film should be lifted, and re-covered at 3 p.m. If the temperature is too high, pollen dies; if the temperature is too low, pollen activity is insufficient and pollination is difficult.

5. Greenhouse cultivation

Strawberries grown in greenhouses in early spring can flower and bear fruit.

6. Open-field cultivation techniques

Open-field strawberry cultivation can adopt two methods: one planting per year or one planting for many years. The former rotates with other crops after harvest each year; under this system, strawberries have strong vitality, good fruit quality, early maturity, and few pests and diseases. However, the key technique is to cultivate strong seedlings with more than 3 leaves and a well-developed root system, and appropriate dense planting can be used. Plant once, harvest for many years, transplant in autumn, and harvest in May of the following year. After 3 years, renew once using runner seedlings.

(1) Land preparation and base fertilizer application

Strawberries have shallow roots and are best grown in loam or sandy loam with good permeability and rich organic matter. The previous crop is preferably wheat, beans, melons, or vegetables. They can also be intercropped with tall-stalk crops. Deep-plow the land early, apply 3000 kg of fully decomposed manure as base fertilizer per mu, and sun the soil. When preparing the land, apply 25 kg of diammonium phosphate and 10 kg of potassium chloride. Irrigate once with a small amount of water before planting.

(2) Planting

Before transplanting, select seedlings with 5-6 compound leaves, robust plants, and intact root systems, and plant them in the field on cloudy days or in the evening. The planting density is (20-25) cm × (25-30) cm. Plant the seedlings so that they are shallow enough not to expose roots and deep enough not to bury the heart. After planting, irrigate once thoroughly; after the water dries, promptly check the condition of the seedlings, loosen the soil, earth up, or fill gaps. When planting, make the curved back of the seedling face toward the inside of the flat bed, which facilitates management and fruit harvesting.

(3) Field management

After strawberry planting, water to settle the roots, then keep the field moist, lower the soil temperature, and irrigate timely and appropriately according to field humidity. When irrigating with overwintering water, apply 15-20 kg/mu of compound fertilizer to improve overwintering ability. Spring flowering and fruiting is a water-sensitive period, and the soil should be kept moist. When irrigating, apply nitrogen-phosphorus compound fertilizer or spray foliar fertilizer; do not use too much water, and promptly drain accumulated water. At the same time, before flowering, at the young fruit stage, and at the fruit enlargement stage, promptly spray Caiguo Zhuangdiling to increase the strawberry's cyclic fruit-setting rate and promote fruit development. After strawberry transplanting and survival, cultivate frequently and weed. After fruit harvest, earth up at the appropriate time. In winter, appropriately use ground cover to prevent cold, keep warm, and help strawberries overwinter smoothly. Nowadays, plastic mulch covering is mostly done from late January to early February, which can promote earlier ripening of strawberries and extend the harvest period.

II. Why aren't the strawberries you grow sweet? It may be because of these 5 reasons!

1. Small day-night temperature difference

We all know that many fruits taste sweeter when grown in environments with a large day-night temperature difference, because higher daytime temperatures and lower nighttime temperatures help the fruit accumulate sugar. If strawberries aren't sweet, this is largely the reason. When growing them, use a greenhouse to raise the daytime temperature and strengthen ventilation at night to lower the temperature, artificially increasing the day-night temperature difference; strawberries grown this way will definitely be sweet.

2. Insufficient light

During the peak growth season and the flowering and fruiting period, strawberries have a relatively high light requirement and need 12-15 hours of light per day. Grown under sufficient light, strawberry plants grow vigorously, produce many flowers and fruits, and the fruits are sweet and large with relatively high yield. Conversely, if light is insufficient, strawberry plants grow weakly, leaves are dull, flowers are small and few, fruit coloring is poor, the fruit isn't sweet, and yield is low. Therefore, when growing them, be sure to ensure the light duration for strawberries.

3. Improper watering

Strawberries have a relatively high water requirement during the growing period, but at the fruiting stage, especially during fruit enlargement, if too much water is given, the roots absorb too much water, which not only is unfavorable for sugar accumulation in the fruit but also easily causes root rot and seedling death, and the resulting fruit tastes extremely sour. Therefore, during the strawberry fruiting period, be sure to pay attention to the amount of watering; never water too much. Water according to the dry and wet condition of the soil, and water only after seeing that the soil has dried.

4. Poor fertilization

Strawberry growth requires sufficient nutrients, but the nutrients in the soil cannot supply what it needs for growth, let alone flowering and fruiting, so fertilization during cultivation is also crucial. For fertilization, it is recommended to use farmyard manure or organic fertilizer, and apply less chemical fertilizer. Generally, apply 4000-5000 kg of farmyard manure per mu, combined with some organic fertilizer or compound fertilizer.

5. Improper management

When growing strawberries, to prevent them from excessively consuming nutrients, pruning must be carried out at different stages. Removing strawberry runners at the right time and in the right amount can increase yield by about 50%; excessive runners consume a large amount of nutrients, so runners should be removed immediately when they first grow out, ensuring the fruit is large and sweet. Also, at the bud stage, appropriately remove flower buds and thin the buds to avoid excessive nutrient consumption and promote fruit set. In addition, strawberries grow new leaves throughout the year, so promptly remove old leaves or diseased branches and leaves, which can reduce nutrient consumption and also enhance permeability.