A variety of leafy veg provide greens in this late winter garden
Lettuce, Endive and Corn Salad
Lettuces come in an amazing number of varieties and in many areas a year round supply is possible. There are the small, tasty butterhead types called mignonettes (red and green), the upright types that you tear leaves off as you need them and the more common cabbage head types. The heading varieties all have one thing in common. That is they have a very short harvest life (about two weeks). As a consequence, they are best sown in small amounts, frequently. Alternatively, you can grow only the loose-leaf sorts and take what you need, leaving the plants to grow on.
Lettuces have the undeserved reputation of being difficult to grow. Providing you understand their requirements, you can grow lettuces with great success. They are shallow rooted. Cultivate shallowly, if at all. Since they also have a high water requirement, regular and frequent watering is needed. Mulching helps, but regular checking of the moisture content of the soil are advisable. A temporary water shortage makes the lettuce very bitter and/or run to seed. Lettuces are also prone to mildews that are exacerbated by moist leaves, so flood irrigation is preferred where possible. Failing that, water in the morning, before sunrise, to allow the leaves to dry quickly before the water droplets can focus the sunlight and burn the leaves.
Lettuces are a hungry crop, so feed them copious quantities of well rotted compost before sowing direct or transplanting. Lime is needed to bring the soil up to a pH of about 6.5. Some growers give side feeds of nitrogenous liquid manure throughout the growing period, to increase their size. This is unwise for several reasons. First, increased levels of nitrate in the soil are translated into nitrosamine in the plant. This is a toxic substance that causes "blue baby" syndrome in infants. Second, the elevated nitrate levels in the plant are an attraction to pests and diseases. Third, the plant's increased size is a result of the extra water the plant takes up in response to the elevated nitrate levels. In other words, you are diluting the nutrient value and flavour of the lettuce. Since they have precious little flavour in the first place, gourmets will resist the temptation to engage in the foolish pursuit of size at any cost.
Lettuce seed needs to be chilled before sowing during the warm summer months. Put the seed in the fridge for seventy-two hours before sowing. The seeds should be sown shallowly in punnets, pots, flats, or direct where they are to grow. The plants should be spaced 25-30 cms apart. Transplanting increases time to harvest by about two to three weeks. Some growers sow at a close spacing and transplant the extra seedlings to spread out the harvest.
In hot areas, it is advantageous to sow lettuces where they will get a little shade from neighbouring plants during the heat of the day. Sweet corn, sunflowers, and climbing beans all make suitable companions for this purpose. Transplanting during the hotter months may require temporary shade, such as boards placed across the bed supported on bricks.
Different varieties have different seasonal requirements and, to a degree, different times to maturity. Sowing a hot weather lettuce in the autumn or an Imperial strain in summer will give poor results. You should experiment to find the varieties that do best in your locality at different times of the year. Cos lettuce, lamb's lettuce (corn salad) and Endive (a sort of chicory) all grow during the cooler months of the year. Endive, also known as curly lettuce, should be blanched to remove the bitter taste. Blanching can be by tying the leaves together at the top, or by covering with a box for a week before harvest.
The major pests of lettuces are snails and slugs. Snails are creatures of habit that live away from their feeding area, so barriers are effective against them. Slugs live in the lettuce and require more stringent control. The section on Snails and Slugs contains several strategies for dealing with these slimy creatures.
Silver Beet and Spinach
Silver beet is called spinach in some parts of Australia, but they are really two different vegetables. Silver beet will produce all year round from two or three sowings. Spinach, though, is a cool climate crop and will bolt, or run to seed in hot weather. Other leafy vegetables are also eaten as 'spinach', and these include New Zealand spinach, orach, stinging nettles, fat hen, and amaranth. They are all heavy feeders, requiring copious quantities of compost in the soil. The warning given regarding supplementary feeding of lettuce applies equally to these leaf vegetables.
Silver beet and spinach have been bred into a multitude of garden varieties and in the process have lost a lot of vigour compared to the 'wilder' members of this group. Another consequence of this breeding has been a reduction in the amount of minerals taken up. Not only are the so-called weeds in this group richer in minerals, they are stronger flavoured. Nettles make a particularly flavoursome and nutritious soup. They should be gathered with gloved hands and wilted. A five minute simmer totally eliminates the sting.
Spinaches have been highly praised for their nutritional qualities and condemned because they contain oxalic acid. While an excess is certainly not good for you, they fulfil an important role in the 'hungry gap'. The period in spring when you are waiting for the early carrots, broad beans and peas, are totally sick of winter brassicas, is filled with this wonderful variety of leafy greens.
While silver beet and spinach are high in oxalic acid, some cultivars are lower in this toxin. The silver beet called Lucullus, known as Snaebeet by the Dutch, has a better flavour on this account. It is less vigorous and a paler green than the Fordhook type, and on this account less favoured commercially. The conventional silver beet varieties do less well over the winter in the district where I live, so Lucullus is held in high regard.
All of this group should be sown direct where they are to grow. While transplanting is possible, they will establish better when sown direct. Since they are mostly cut-and-come-again, the more vigorous they are, the longer they will last before running to seed.