Variety Selection

For tomato cultivation in sunlight greenhouses with a late autumn sowing, choose varieties that have strong fruit-setting ability under high temperatures, are heat-tolerant, produce large fruits, and have strong resistance to diseases. Suitable varieties include "Beiying," "Paulotari," and "Deniuman," among others.

Seedling Cultivation

Tomato seeds are small, so using a 72-cell small-diameter plug tray is generally recommended for seedling cultivation. Choose a substrate with good water retention properties (peat: perlite: vermiculite in a volume ratio of 7:1:2). To ensure the quality and quantity of the seedlings, it is best to use imported peat for the substrate. After preparing the substrate, treat it with a 1,000 times dilution of 75% carbendazim wettable powder before use. Fill the trays uniformly, maintaining a loose texture. After filling the trays, proceed with sowing the seeds at a depth of 1.0-1.2 cm. Cover the sown seeds with vermiculite or perlite to prevent the seedlings from emerging with the seed coat attached. Water thoroughly after sowing and maintain the temperature at 25-28°C. After watering, cover the trays with a thin film and place a thermometer to monitor the temperature. Remove the film when 30%-40% of the seedlings have emerged to prevent seedling burn.

Ridging and Transplanting

Turn the straw mushroom residue directly into the soil, level the ground, and create ridges or high beds with a row spacing of 75 cm. When the seedlings have grown to the four-leaf and one-heart stage, select uniformly strong seedlings and transplant them in the afternoon. Before transplanting, soak the roots in a 1,200 times dilution of 30% metalaxyl-mefenoxam suspension for about 10 minutes. Allow the seedlings to dry slightly and then transplant them at a plant spacing of 35 cm. After transplanting, cover the ground with a plastic film.

The transplanting depth should be such that the seedling's nutrient block is level with the soil surface, ensuring the nutrient block is not entirely buried to prevent seedlings from soil-borne diseases. The seedlings should be planted precisely in the center of the hole. After transplanting, water thoroughly to promote acclimatization.

Post-transplanting Management

**Temperature Management**
After transplanting, focus on promoting root development. Generally, do not water immediately after transplanting and maintain daytime temperatures between 27-30°C and nighttime temperatures between 18-20°C. After the seedlings acclimate, adjust to daytime temperatures of 23-27°C and nighttime temperatures of 14-16°C. During the flowering and fruiting stages, maintain daytime temperatures of 25-27°C and nighttime temperatures of 12-16°C. In the autumn months of October and November, ensure stable temperature conditions.

**Humidity Management**
Control air relative humidity to be between 50% and 60%, and soil moisture to be between 65% and 80%. Avoid excessive flooding; instead, water lightly but frequently. During deep winter, enhance ventilation to reduce humidity and use under-mulch irrigation or drip irrigation to lower air humidity.

**Light Management**
Clean the greenhouse film with a dry mop every 3 days, three times in total, to increase light transmittance. In low-light conditions, raise the grass curtain as long as it does not lower the greenhouse temperature to increase light exposure and meet the plants' growth and development needs. In mid-November, hang reflective screens or films on the back wall to increase light and enhance growth through added warmth.

The SmartFarm All-in-one sensor provides real-time monitoring of light levels in the greenhouse. The sensor reports data every 20 seconds and can be configured to send alert messages when minimum or maximum light values are reached, making cultivation more data-driven and scientific.

The SmartFarm All-in-one sensor provides real-time monitoring of temperature and humidity data within the greenhouse. The sensor reports data every 20 seconds and can be configured to send alert messages when minimum or maximum temperature values are reached, making cultivation more data-driven and scientific.

**Fertilization and Water Management**
Avoid fertilizing before the first cluster of fruits. Apply the first round of fertilizer when the third cluster of fruits reaches the size of walnuts, using 7-10 kg of potassium carbonate and 3-4 kg of calcium nitrate per 667 square meters, applying 1-2 times per cluster. After harvesting the first cluster of fruits, apply the second round of fertilizer. Combine this with foliar spraying of potassium dihydrogen phosphate, spraying once every two weeks starting from the harvest period.

From mid-February to mid-March, water every 15 days, and apply 20 kg of NPK compound fertilizer per 667 square meters with the irrigation. From mid-March to the end of May, as temperatures rise, increase fertilization and water management. Water every 7-10 days, applying 7-10 kg of potassium carbonate and 3-4 kg of calcium nitrate per 667 square meters with each irrigation.

Using the SmartFarm water and fertilizer integration system allows for remote control of irrigation or intelligent irrigation in combination with soil moisture sensors. This not only saves labor, water, and fertilizer but also ensures that tomatoes consistently grow in an optimal soil environment.

**Plant Management**
Train the plants to a single stem, topping the main stem after leaving 6-7 clusters of fruits. When the first cluster of fruits reaches the size of an egg, leave 1-2 leaves below the first cluster and remove all other leaves. Depending on the cropping schedule, after reaching the desired number of clusters, leave 2-3 functional leaves above the last cluster to produce nutrients for the lower fruits. Before the first cluster blossoms, support the plants with strings to ensure they grow orderly and do not shade each other from sunlight. Additionally, remove side shoots to maintain a single-stem structure and avoid unnecessary nutrient consumption.

Timely thinning of flowers and fruits is essential. Generally, leave 3-4 fruits on the first cluster and 4-5 fruits on each subsequent cluster. Remove any excess flowers or fruits promptly to improve the marketability of the fruits.