Wednesday, 18 June 2008

Tomato Plant Varieties

Tomato fruits come in a very wide range of sizes, shapes and colours. The largest are the American "beefsteak" and the roughly shaped European "Marmande" types - both considered well flavoured. Some exceptionally thick walled American types which are easily hollowed out are ideal for stuffing. Smaller tomatoes include "cherry" tomatoes, up to 2.5cm (1in) in diameter, and the tiny thumbnail sized "currant" tomatoes. Italian "plum" tomatoes, widely used for canning, are elongated; so is "Britain's Breakfast", a solid fleshed cultivar which freezes well. There are also pear shaped types. Tomatoes can be striped, red, pink, orange or yellow.

Opinions vary widely about the comparative flavour of different cultivars. Flavour is determined by both acidity and sweetness; these characters may be inherent in the cultivar, but are also influenced by watering, feeding, sunshine, growing methods and the stage when picked. The first fruits on a truss are normally the best flavoured. Over watering and over feeding probably lead to diminished flavour.

There are several types of tomato plant. The tall types are "indeterminate", in that a main shoot will grow indefinitely, given warm conditions; eventually it will reach a height of several metres (yards). This type is grown as "cordons", by removing the side shoots and tying the plants to some kind of support. Most greenhouse tomatoes belong to this group.

In the "bush" type there is rarely a main shoot but a number of side branches develop, which more or less stop themselves, to produce a somewhat sprawling, bushy plant. These can be grown without supports and are therefore useful under cloches or floating mulches. Generally, they have a shorter productive season than tall types. Many of the cultivars grown outdoors are of this type.

The "dwarf" types form miniature, very compact plants, sometimes no more than 20cm (8in) high, with only a few short side branches. They are generally low yielding, and mainly used for growing in pots, or on window sills.

Tomato cultivars are divided roughly into greenhouse and outdoor types, but in practice outdoor tomatoes can be grown indoors, and most greenhouse cultivars outdoors, except those bred specifically for heated greenhouses. Some modern greenhouse cultivars have resistance to the wide range of diseases encountered in greenhouse conditions but generally avoided outdoors.