Lettuce
Spacing
This depends on your choice of plants and how you arrange your garden. Rows are traditional but require more space and so can be difficult to manage in a small garden. Many people prefer "patch-work" planting, which reserves small areas of one or two square feet each to fill with plants. Not much more than a window box or a large pot is needed. Micro leaves and baby salad leaves are favourites for slugs and snails, so growing them in containers can make protecting them easier.
Growing
Lettuce grows best in the sun, but not in high heat. The high heat of summer can cause lettuce to bolt, which is when the lettuce goes from a nice short rosette of leaves to a tall flowering seed head. And the worst part is when this happens the lettuce becomes bitter. Also, high summer soil temperatures can prevent some varieties from germinating. So, find a place that has sun but won’t get too hot, a bit of shade wouldn’t be a bad thing, such as an east, or morning, sun area. Also make sure that the soil is nutrient rich and well drained, never waterlogged. Consider amending your soil with an organic fertilizer. Lettuce and other salad greens are well suited to growing in containers and grow-bags, which also has the benefit of being able to move them about to get the best growing conditions.
Sow seeds from mid-spring to late summer. The easiest way to sow the tiny seeds of salad greens is to sprinkle them lightly on the soil surface then finely cover with about 1 cm of soil. As the seed germinate, thin out some seedlings and add them to your salad. This gives more room for the remaining plants to grow. Thin seedlings as soon as the first true leaves appear and continue until the plants are 30cm apart. Water when the soil is dry, preferably in the early morning. This gives the plant more time to absorb the water and helps to keep the slugs away (who like moist evening conditions). Early in the year sparrows can be a problem as they find young lettuce plants irresistible. Protect with Remay cloth, chicken wire or something to physically keep the birds from your crop.
Harvesting
Salad leaves are known as cut and come again crops. This means when the plants reach between 10-15cm tall you can cut the entire plant to just 2.5cm tall and the plants will regrow and can be harvested again in 3-4 weeks. However, after several cuttings the leaves can start to taste bitter, particularly in hot weather or if they’ve bolted. Spent plants that are weak, bitter or unproductive should be removed. Harvest leaves just before you want to eat them or store in the fridge for a few days. You will usually be able to cut the salad leaves three or four times, so the secret to having salad leaves all summer is to sow several times at 14-day intervals. So, once you finish with one crop, you can start the next.
Cultivars for Use
While green leafy lettuces may be the backbone of a salad, there is so much other colour and texture available. Try planting a bistro salad mix, mesclun mix, arugula, radicchio, Swiss chard, spinach, rumex, frisée, watercress, mache and sorrel. Herbs such as dill, parsley, cilantro, basil, and chervil can be a great tasty addition to
your salads as well. But if green leafy lettuce is what you are after then why not try these differently types of head lettuces:
- Butterhead lettuces have an open habit, they are quick-maturing and tolerate poorer growing conditions.
- Cos types have an upright growth habit and oblong head, such as romaine.
- Crisphead types produce large hearts of curled and crisp leaves and are more resistant to bolting. This group includes the ever-popular iceberg lettuces.