Detailed Explanation of Key Cultivation Techniques for Late-Autumn Greenhouse Tomatoes
Tomato is a food with high nutritional value. It can be eaten raw or cooked, and it has a distinctive flavor. Tomatoes are generally planted in spring, but to be able to eat tomatoes in other seasons as well, autumn greenhouse planting is chosen. Let's take a look below at the key cultivation techniques for late-autumn greenhouse tomatoes.
1. Choosing the right variety is key
Varieties with strong disease resistance, early maturity, high yield and good storage tolerance should be selected. Varieties commonly used in production at present include: Tropique, Floradel, Jiafen No. 1, Jiahong, Qiangfeng, Shenfen No. 1, L401, Zhengfan No. 2, Tinghong No. 2, etc. Each locality should make a specific choice according to local characteristics.
2. Determining the appropriate sowing period and seedling-raising method
If autumn greenhouse tomatoes are sown too early, the seedling stage coincides with the hot, rainy season and the incidence of viral disease is high; if sown too late, the growth period is insufficient and the fruit on the third cluster at the top cannot ripen. The suitable sowing period should be about 110 days back from the time when the local temperature reaches around minus 5 degrees C. In Liaoning and Jilin, mid-to-late June is suitable. If only two clusters of fruit are kept per plant, the suitable sowing period can be postponed by 4-5 days.
Greenhouse tomato cultivation can be done by direct sowing or by raising seedlings and transplanting. With direct sowing cultivation, the root system is not damaged, the plants grow vigorously, and the yield per unit area is relatively high, but intertillage loosening of the soil and spraying to control insect pests in the early stage require a lot of labor. For autumn greenhouse tomatoes, seedling raising and transplanting can use small-seedling transplanting (transplanting of seedling with cotyledon and first true leaf), or large-seedling transplanting. Small-seedling transplanting is generally done at the two-leaf-one-heart stage, planting the small seedlings with soil into the greenhouse; the seedling age is 15-18 days, at which time the secondary lateral roots of the plant have just extended and the root spread is not large, so few roots are damaged at transplanting and the seedlings recover easily. After small-seedling planting, watering must be timely, otherwise the soil easily becomes compacted and causes "neck-snagging" and loss of seedlings. Large-seedling transplanting is currently the form generally adopted in production. During seedling raising, seedlings are transplanted once (divided) at 2-3 leaves; when the seedlings grow to 5-6 leaves and the calendar seedling age is about 25 days, they are cut into blocks for transplanting or removed from the nutrient bags for transplanting. The advantage of this method is that centralized management during the seedling stage is convenient, and transplanting is late, which facilitates crop rotation and reversing the soil, but late transplanting leads to more severe disease. In actual production, the use of direct sowing or small-seedling transplanting for autumn greenhouse tomatoes is often more favorable for high and stable yields than large-seedling transplanting. For overwintering tomato seedling raising, shade nets can be used for shaded seedling raising to reduce disease and cultivate strong seedlings.
3. Land preparation and transplanting
Before transplanting, clean the field and prepare the land and apply fertilizer. Generally, about 5000 kg of decomposed farmyard manure is applied per mu. Autumn tomatoes can be cultivated in beds or on ridges. The planting density is generally greater than that for early spring cultivation. For cultivation of determinate varieties or cultivation keeping only two clusters of fruit per plant, about 5000 plants are planted per mu. For cultivation of indeterminate varieties with 3 clusters of fruit kept per plant, about 4000 plants are planted per mu. It is best to transplant on a cloudy day or in the evening, and water promptly to help the seedlings recover.
4. Management work after transplanting
After transplanting, ventilation and cooling should be strengthened. Intertillage and loosening of the soil should be done in time. If the plants grow excessively, chlormequat chloride should be sprayed in time. During the flowering period, fruit-setting hormones such as 4-CPA should be sprayed or dipped in time, and pruning, removal of side shoots and vine tying should be done in time; single-stem pruning is generally used, and the growing point is removed after keeping 2-3 clusters of fruit. After mid-September, the outside temperature begins to drop, so attention should be paid to keeping warm at night. After the first cluster of fruit has set, water and fertilizer management should be strengthened.
5. Pest and disease control
In the early stage, autumn greenhouse tomatoes suffer relatively severe viral disease, and in the later stage, diseases such as leaf mold, early blight and late blight are relatively severe, so control should be strengthened. For insect pests, aphids, whiteflies and cotton bollworms, etc. should be controlled.
6. Harvesting
After the fruit of autumn greenhouse tomatoes changes color, they should be harvested successively for market. When the temperature inside the greenhouse drops to 2 degrees C, all of them should be harvested and stored.