How to practice successful lettuce farming
Lettuce is a leafy vegetable that is eaten raw as a salad or cooked.
It has a crunchy texture with a mildly sweet taste but is hardly consumed in many households in Kenya.
Its health benefits include improving digestion, promoting weight loss, inducing sleep, improving memory retention, hydration, controlling anxiety, promoting muscle development, skincare benefits and it has anti-cancer properties.
There are two main varieties of lettuce namely: Headed which forms a compacted cabbage-like head, and non-headed lettuce also known as loose leaf, cutting or bunching lettuce which is usually in high demand notes farmbizafrica.com
The loose-leaf lettuce has more uses than the headed lettuce such as making salads and other foods such as soups and sandwiches or either grilled.
Some of the commonly grown lettuce varieties as listed by greenlife.co.ke include;
- Butterhead; has loose leaves and buttery texture. Ready for the first harvest in 45-55 days after sowing.
- Crisp-head; forms tight, dense heads that resemble cabbage. It is the mildest form and valued for its crunchy texture than flavour. Ready for the first harvest in 70-100 days after sowing.
- Loose-leaf; has tender, delicate and flavourful leaves with a loose bunch and is mainly used for salads. Ready for the first harvest in 45-55 days after sowing
- Romaine lettuce; grows to a long head of sturdy leaves with a stout rib almost reaching to the tip of the leaf blade. It is used mainly for salads and sandwiches and is ready for first harvesting in 75-85 days after sowing.
- Chinese lettuce; forms long, tapering, non-head forming leaves and has a strong-flavored the tuff of terminal leaves.
- Summer crisp; forms moderately dense heads with a crunchy texture. The variety is intermediate between crisp-head and loose-leaf varieties.
Lettuce does well in relatively cool temperatures and requires ample sunlight, uniform cool nights and plenty of soil moisture for optimum growth and production.
It requires temperatures ranging from 18 to 22 degrees Celsius during the day and seven to 110 degrees Celsius at night highlights farmbizafrica.com
Lettuce can be grown on a wide range of soils which are fertile and well-drained loam soils rich in organic matter with good water retention and soil PH of 5.5 to 7.2
Lettuce is grown from seed which can be sown directly in the fields or raised in a nursery bed before being transplanted later.
The seeds take three to four days to germinate and are ready to transplant in four to five weeks with four to six leaves and a well-developed rooting.
Land should be prepared to a fine tilth and compost manure applied. The ideal spacing is 30 by 30cm or 25 by 25cm depending on the variety.
Irrigation should be reduced a week before transplanting to harden the seedlings.
Farm practices done to maintain lettuce and ensure the bountiful production entail weeding which ensures the plant does not compete for nutrients, water, sunlight and space as well as keeping off pests causing diseases.
Mulching should be done to conserve as much moisture for the lettuce, add soil fertility on decomposing, keep off pests and diseases, avoid soil erosion and keep off weeds.
In a dry season, the farmer should water the lettuce regularly to have adequate moisture.
Crop rotation with legume cereals is also encouraged to enrich the soil and avoid pests and disease build-up.
Well decomposed farmyard manure can be added to boost the soil fertility to achieve maximum yields.
Pests and diseases
Common pests known to attack lettuce as listed by greenlife.co.ke include aphids, cutworms, diamond black moth, caterpillars and American bollworm which are controlled by spraying with appropriate pesticides and insecticides.
Diseases that infect lettuce are damping off, Downey mildew, leaf spot, powdery mildew, bacterial rot, and lettuce mosaic virus which are controlled by applying recommended fungicides.
Lettuce takes averagely from 45 to 100 days to mature and be ready for harvesting depending on the variety.
Headed lettuce is harvested when the head is fully grown and firm while the loose leaf when the leaves have reached the desired leaf size.
Harvesting is done by cutting the plant off just above the soil surface to keep most of the outer leaves around the head and should be done very early in the morning or late in the evening to avoid wilting.
The crop is highly perishable. Under refrigeration, lettuce can be stored for up to three weeks.