How to Grow Red Leaf Lettuce? A Detailed Guide to the Key Growing Techniques

When it comes to red leaf lettuce, quite a few people are probably unfamiliar with it, since it is relatively rare in daily life. Red leaf lettuce is actually a variety of lettuce, named for its purple leaves; it can be eaten raw or stir-fried, and there are many ways to enjoy it. So do you know how to grow red leaf lettuce?

How to Grow Red Leaf Lettuce

1. Sowing period: Red leaf lettuce can be cultivated at any time of year except the hottest season.

2. Choosing a seedling-raising site: For year-round production in the Beijing area, the seedling-raising site is open ground and protected ground for half a year each. Usually, in April, May and September, red leaf lettuce seedlings are raised in open ground. In June, July and August, sun-shading and rain-proofing measures must be taken. From October to March of the following year, seedlings must be raised in protected ground.

3. Sowing: Growing 1 mu of red leaf lettuce requires 12-15 sq m of seedbed, and dry seed is usually sown directly. However, in summer and early autumn, red leaf lettuce emerges with difficulty, so it is best to sow after germination. The sowing rate is 15-20 g. For spring and autumn seedling raising in open ground, if quick emergence is desired at sowing time, film coverings can be added to increase temperature and preserve soil moisture, then removed after emergence; for summer seedling raising, sun-shading, cooling and rain-proofing measures must be taken. During the seedling stage, watering is needed, and for seedlings raised in plastic trays in particular, more spraying is required: once a day in winter and spring, and three times a day in summer. No topdressing is needed during the seedling stage. When raising seedlings in protected ground, attention must be paid to temperature management; the suitable germination temperature is 18-20°C. When room temperature is insufficient in winter and spring, those raising seedlings in solar greenhouses should try to get more light during the day and add coverings at night to protect against cold and preserve warmth.

4. Transplanting seedlings: When about 10 days after sowing the cotyledons are fully grown and two true leaves have appeared, the seedlings can be transplanted. For transplanting, soil-raised seedlings or nutrient-soil block seedlings can be used, with a spacing of 5 cm × 5 cm. The suitable temperature for seedling growth is 20°C during the day and 12-14°C at night. Before planting in winter and spring, the temperature must be lowered to harden the seedlings. When the seedlings have grown 4-5 leaves, they are ready to be planted out.

Growing Techniques for Red Leaf Lettuce

1. Cultivation and planting out of red leaf lettuce

When growing red leaf lettuce, the seedlings must first be raised before planting. For seedling raising, soak the red leaf lettuce seeds in warm water, then take them out to germinate; only after the seeds have sprouted can they be sown into the seedbed, and when the seedlings have grown three leaves they are transplanted. Before transplanting, 3,000 kg of organic fertilizer should be applied per mu, and the ground should be leveled well. After planting out, red leaf lettuce should be watered promptly.

2. Management of red leaf lettuce

During the growing period, red leaf lettuce has high water requirements; the soil should not be overwatered, nor should it be allowed to become too dry. Growers can adjust according to weather changes, and during the growing period of red leaf lettuce, topdressing should also be applied once: 100 kg of chicken manure per mu, plus 20 kg of compound fertilizer. During the growing period, red leaf lettuce sometimes suffers from aphids, which need to be promptly controlled by spraying, otherwise the lettuce leaves that grow will have many small holes bitten by insects, affecting the quality of the red leaf lettuce.

Growing Environment

Red leaf lettuce is a semi-cold-tolerant vegetable that prefers cool conditions and cannot tolerate high temperatures. Seeds can germinate slowly at 4°C; the suitable germination temperature is 18-20°C; at 25°C the germination rate drops greatly; above 30°C germination is blocked. The suitable temperature for growth during the seedling stage is 16-20°C. Seedlings that have undergone low-temperature hardening can briefly endure low temperatures of -1 to 2°C and can tolerate light frost to some extent.

Red leaf lettuce likes sufficient sunlight, and seeds germinate quickly in light; conversely, when there are many cloudy days, the leaf shape becomes small and slender, and the plants grow thin and weak.

Red leaf lettuce likes a moist environment and cannot tolerate drought. During the period of seed germination and emergence, sufficient water is needed; keeping the seedbed soil moist helps the seeds germinate, emerge and the seedlings grow, but it must not be too dry or too wet, so as to avoid the seedlings becoming aged or growing leggy.

Red leaf lettuce has wide adaptability to soil, but sandy loam rich in organic matter, with good aeration and strong water- and fertilizer-holding capacity, is most suitable. Red leaf lettuce has a short growing period and fast growth, so it must have a sufficient fertilizer supply, requiring sufficient nitrogen fertilizer along with phosphorus and potassium fertilizer. A phosphorus deficiency at the seedling stage makes plants short and small with few leaves, dark green leaf color and weak growth, while a potassium deficiency affects leaf weight.

Main Value

Purple vegetables contain a most special substance — anthocyanins. In addition to strong antioxidant capacity, preventing high blood pressure and slowing liver dysfunction, anthocyanins also have great effects on improving eyesight and preventing eye fatigue. Because purple vegetables have unique nutritional components, their nutritional value is higher than that of ordinary green vegetables, and their market prospects are relatively good, making them a future development direction for vegetable varieties.

Red leaf lettuce is extremely nutritious. It contains anthocyanins, carotene, vitamin E, vitamins B1, B2 and B6, and is also rich in minerals such as phosphorus, calcium, potassium and magnesium, as well as small amounts of copper, iron, zinc and selenium. Its benefits to the human body include aiding digestion, stimulating bile formation, cooling the blood, promoting blood circulation, diuresis, calming, aiding sleep, preventing the accumulation of waste in the intestines, and having anti-aging and anti-cancer functions. It can also be grown as a foliage ornamental potted plant, placed on a balcony, where it can be both enjoyed visually and eaten.

The above is the red leaf lettuce growing method summarized for everyone by the editor. I hope it can help you! In fact, red leaf lettuce is even more nutritious than ordinary lettuce; because it is relatively rare, many people do not know about it. Friends who grow lettuce might as well try switching to growing red leaf lettuce next time!