Efficient Greenhouse Tomato Irrigation Helps to Improve Yield and Quality

Provide stage-specific tomato irrigation strategies based on their water needs at different growth stages, maximizing water use efficiency and ensuring adequate water supply during critical periods.

Crop Cycle

The growth cycle of tomatoes in a greenhouse generally ranges from 6 to 10 months (depending on the variety), and the climatic conditions required vary at different growth stages. After sowing, seedlings emerge in about 7 to 10 days, after which appropriate fertilization, watering, and temperature maintenance are necessary. During the fruit ripening period after flowering, it is necessary to pay attention to avoiding pest and disease infestations.

Irrigation Recommendations under Different Growth Factors

Tomato irrigation flow rate is usually dynamically adjusted according to the crop's growth stage, soil type, and climate conditions. It is recommended to use a drip irrigation system with a flow rate of 1–4 L/H/plant to ensure effective water utilization and to avoid water waste and crop diseases.

Table 1: Irrigation Recommendations for Different Growth Stages
Growth Stage	Seedling Stage	Flowering Stage	Fruit Expansion Stage	Maturity Stage
Irrigation recommendations	Moisture demand is relatively low, and the flow rate should be controlled at 0.5–1 L/H/plant.	Water demand increases, and the flow rate can be increased to 1–2 L/H/plant.	This is the stage with the highest water demand for tomatoes, and the flow rate should be adjusted to 2–4 L/H/plant.	Appropriately reduce the irrigation flow rate, maintaining it at 1–2 L/H/plant to avoid fruit cracking.

Table 2: Irrigation Recommendations for Different Soil Types
Soil Type	Sandy Soil	Clay Soil	Loam
Irrigation recommendations	Water penetrates quickly but has poor retention capacity, requiring more frequent irrigation with a lower flow rate per session, about 1–2 L/H/plant	With strong water retention capacity, the irrigation frequency can be reduced, but the flow rate per irrigation should be appropriately increased to 2–3 L/H/plant.	Generally between sandy and clayey soil, the flow rate can be adjusted between 1–2.5 L/H/plant.

Table 3: Irrigation Recommendations under Different Climate Conditions
Climate Conditions	High Temperature And Dry	Humid Climate
Irrigation recommendations	With high evaporation, the irrigation flow rate should be increased to 3–4 L/H/plant.	With low evaporation, appropriately reduce the irrigation flow rate to 1–2 L/H/plant.

A drip irrigation pipe is watering tomato seedlings.

Many drip irrigation pipes are irrigating tomatoes.

Irrigation Flow Rate Calculation Method

Calculate as needed
Calculate based on the daily water demand of tomatoes and the number of plants.
For example, if the daily water demand for tomatoes is 0.5 liters and there are 1,000 tomato plants, then the daily irrigation flow rate demand is 500 liters. If using a 2-hour irrigation period, 250 liters of water are needed per hour. Assuming 100 drippers are used, each dripper should have a flow rate of 2.5 L/hour.
Based on reference data
In a typical drip irrigation system, the standard flow rate for each dripper is 1–2 L/hour. The specific choice should be adjusted according to the water demand of tomatoes, planting density, and soil conditions.

Planting Recommendations

Tomatoes are suitable for planting in soil with a pH value of 5.5–6.5.
When the soil pH value is higher than 7.5, tomatoes are prone to deficiencies in boron (B), copper (Cu), iron (Fe), manganese (Mn), phosphorus (P), and zinc (Zn).
When the soil pH value is lower than 5.5, tomatoes are prone to deficiencies in phosphorus (P), molybdenum (Mo), and calcium (Ca).
The optimal growth temperature for tomatoes is 18–27 °C; too high or too low temperatures will affect the physiological functions and metabolic activities of the plants. If the temperature exceeds 34 °C and moisture supply is insufficient, the photosynthesis of tomatoes will be inhibited, affecting growth and yield.