For many gardeners there are few things quite so rewarding as being able to grow some of your own food – it always seems to taste better and, whether or not it really does, there is nothing to beat the feeling of satisfaction. The greenhouse opens up much wider possibilities for growing many vegetables and other crop plants, either out of season or types which otherwise simply could not be grown.
Sowing seeds in the greenhouse as autumn drifts into winter can be a useful way of both providing an early yield of food and making maximum use of greenhouse space. Lettuces, for example, sown in November will be ready to be grown-on under glass in time for an early spring salad. Although any one of the common kinds will do very nicely in this role, it is probably worth trying to get one of the “mixed leaves” varieties to allow you to add maximum interest to plate and palate. It is worth considering keeping the greenhouse crop going into the summer, even when lettuces and their kin can be grown in the main garden or frame and then harvesting the young leaves to use as a tender garnish. In much the same way, many herbs can be grown in pots over the winter – allowing you the luxury of fresh cooking ingredients when the rest of us are relying on dry stuff in pots!
The greenhouse comes into its own, however, with what might be called the truly “hothouse” crops – the likes of peppers, aubergines, tomatoes and cucumbers. Provided you can maintain a minimum temperature of 12 degrees C, several different types of peppers can be grown successfully under glass, including both sweet and chilli peppers. The seeds need to be sown in April and then transplanted into pots as they grow larger. As sweet peppers ripen they turn from green to red, yellow or orange, becoming sweeter as they mature. Ripe hot chilli peppers are red – and should be allowed to fully ripen before they are picked. Varieties such as “Bell Boy” have been developed, which perform particularly well in Britain.
Aubergines – also sometimes called egg plants – are related to peppers and tomatoes, but need a fair amount of warmth to thrive. Soaking their seeds in warm water for a day or so will help them germinate and when the seedlings are around four inches tall they should be transplanted into eight-inch pots and their growing tips pinched out to encourage them to become more bushy. The plants will need some support as they grow. In recent years, heavy-cropping varieties, such as “Moneymaker” (not to be confused with the tomato of the same name) which are well suited to the British climate have become more readily available, making this plant more accessible than ever to the greenhouse grower.
Tomatoes come in a huge range of types, but the upright “cordon” varieties are more suited to greenhouses than a sprawling bush. Sown in mid-March, the seedlings will be ready for transplanting into 12-inch pots in May, equipped with a cane or other suitable support. Any side-shoots between the leaf and stem should be pinched out and later, when five or six trusses of fruit have begun to develop, the main stem itself should also be pinched out to concentrate growth in the ripening tomatoes themselves. Tomatoes are one of the most rewarding of greenhouse crops – a little careful attention and regular high-potassium feeds almost always will guarantee a high yield. Varieties such as “Sunbaby” and “Shirley” are particularly well suited to the greenhouse, producing very tasty fruits with a delicious flavour.
Cucumber-growing has become considerably easier in recent years with the development of a range of readily available F1 hybrid varieties – such as “Femspot F1” – which produce particularly tasty crops. Sowing the seeds individually into three-inch pots in mid-March, by May the plants can be transplanted into 12-inch pots, with wires or canes for support. Once five or six leaves have appeared, the main growing shoot needs to be pinched out and the developing plant trained to the support. Then all that remains is to water well, feed fortnightly with a fertiliser rich in potassium and await the arrival of succulent cucumbers.
With careful selection of varieties suited to growing in the greenhouse – and chosen for their taste and cropping ability – whether brought-on in pots or growbags, a wide range of vegetables and other crops can be grown in even the smallest of greenhouses. While it may well be simpler just to pop down to the local super-market to get the ingredients for your salad, nothing will give you as much satisfaction as knowing that you grew them for yourself.