The container volume for lettuce is selected based on varietal characteristics: leaf varieties require approximately 400 cm³ per plant with a depth of at least 25 cm, while heading varieties require at least 900 cm³ with a depth of 35 cm or more. Due to the shallow root system, the substrate must have high water-holding capacity, although it is critically important to avoid waterlogging, which causes root and lower leaf rot.
Typical substrate mixes for container-grown lettuce include peat, compost, and sand, with the addition of ash and mineral fertilizers. The use of composts based on organic waste contributes to increased productivity and antioxidant activity in plants, but requires strict control of pH levels to prevent the accumulation of heavy metals.
The short vegetation cycle of lettuce (30–35 days) makes the crop suitable for intensive conveyor-style cultivation in compact containers. Unlike crops with taproot systems, lettuce does not require deep containers, which allows for its successful use in indoor or windowsill vegetable gardening.
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Container culture.