Growing lettuce
Lettuces are hardy annual plants making Simons Town with its Mediterranean climate that allows for winter growing, except in Mid-winter (May and June) and mid-summer ideal for a 10-month lettuce growing season.
Lettuce grows best in full sun, nitrogen-rich soils with a pH between 6.0 and 6.8, and is adapted to cool growing conditions with a minimum of 60 F (16 C). However, at 70 )F (30 C, the plants flower and produce seed.
Hence in mid-summer shade cloth is needed to protects plants during the hottest part of the day.
Soil should be organic, loose, well-drained l and moist without staying soggy with no stones, clods of dirt (link)
Seeds should be planted in shallow rows about ⅛ to ¼ of an inch deep to allow the tiny seeds to obtain the light they need to germinate (link).
When the seedlings have 3 to 4 true leaves, they should be thinned.
Seedlings and purchased transplants should have 4 to 6 mature leaves and a well-developed root system before being planted into the garden and watered thoroughly.
Guidelines for planting seeds or transplants for different lettuce types:
Looseleaf lettuce:
Since leaf lettuce is harvested by cutting individual leaves and leaving the growing centre, it is generally planted straight in thick rows and thinned thin to 4 inches apart.
Heading varieties
Lettuces are commonly started in flats, then transplanted to individual spots in the garden after developing several leaves, 8 to 14 inches apart to allow them to receive adequate sunlight , which improves colour and nutrient quantities in the leaves.
Bolting
Bolting is a common problem that's caused by warm temperatures (over 24 C or 75 F).
When a lettuce plant bolts, it starts to produce a central stem and seed stalk, and leaves take on a bitter flavor.
To delay bolting, cover plants with a shade cloth so that they get filtered light and maintain regular watering throughout the warmest parts of the growing season
Leaf lettuce should be grown 4 inches apart
Headed lettuce should be grown 8 to 14 inches apart