How to Grow and Harvest Lettuce
Lettuce has been grown for thousands of years (first by the ancient Egyptians) as an easy to grow food crop and for the oil rich seeds. In modern times it has been cultivated mainly for its edible salad leaves.
There are various types and sub types of lettuce for the South African home gardener.
The following options are available
- Leaf/Looseleaf: Harvested continuously throughout the season as a sustainable mixed leaf salad component
- Cos/Romaine: Cultivated for salads and sandwiches. More conical, upright varieties
- Butterhead: loosely arranged head lettuce cultivated for its sweet flavour and tender leaves
- Iceberg/crisphead: Most commonly cultivate and commercially available lettuce. Very heat sensitive and lower in nutritional value and less flavour due to the unusually high water content. Prized as it has a relatively long shelf life and ships very well
All varieties come in different classifications and, in turn there are a myriad of types to suit everyone's' needs and tastes.
Soil Preparation and feeding for Lettuce
Although relatively low maintenance, lettuces require fertile, well drained soil to thrive and produce consistent good quality healthy leaves and heads. Lettuce roots are fibrous and not very bulky so prepare soil to about 30cm working in about 3cm of compost.
Lettuce plants require no support but would benefit from a couple of centimeters thick layer of mulch around each plant to reduce outer leaf contact with wet soil and to retain soil moisture
Planting times for lettuce in South Africa
Basically all year except for Jul. Some types of Lettuce are better adapted for summer or winter and most types prefer the cooler parts of the year.
Full sun for Winter planting and semi/partial shade for Spring and summer planting.
Seed Planting and Germination
Sow seeds directly into soil in rows or broadcast, or into seed trays 4-6 weeks before transplanting. Seeds should be sown about 3 or 4 times deeper than their diameter.
Lettuce seeds germinate at between 8 and 27 degrees Celsius. At lower temperatures germination will be poor and delayed.
Lettuce seed germination takes approximately 4 to 12 days.
Lettuce Plant Spacing
Days to harvest
Leaf/looseleaf: 45 - 55 days
Cos/Romaine: 75 - 85 days
Butterhead: 45 - 55 days
Iceberg/crisphead: 70 - 100 days
- Days to harvest is based on typical good growing conditions and can sometimes vary depending on climate, state of soil, and in some instances length of day and climate for the area in South Africa where you reside.
- The specific plant might have characteristic/s that fall outside of the typical type norm.
- Days to harvest are counted from germination or seedling transplant date whichever is the latest.
Loose leaf and butterhead lettuces are used in baby leaf mixes as well as once leaves have matured. These varieties are 'pick and pick again' lettuces and, as such can be harvested as for microgreens or baby leaf use from 25 days onward.
Cos/Romaine should be harvested before fully developed when heads are well formed and leaves are a healthy bright color.
Iceberg/crisphead lettuces should be harvested once the head has formed fully and is firm and compact to the touch. Removing yellowing outer leaves allows the plant a few extra days to tighten up their head.
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