Be kind to our salad favourite, urges Val Bourne, so extra warmth can deliver a bumper crop over summer

There ought to be a society for the Prevention of Cruelty to Tomatoes (PCT), for these frost-tender plants from coastal areas of South America are treated awfully badly by garden centres, which plonk them outside in chilly British conditions.

You can see these sad little things hanging their heads, with stunted growth, but the telltale symptom is their blackened foliage.

They’ve had a cold shock and it will knock them back for life, for the tomato needs warmth. Tomatoes should not face a British summer until early June and, even then, most varieties need to be grown under glass in our part of the Britain.

If that were not bad enough, the range of varieties is often very limited and many are not very good.

Moneymaker is like soggy tennis balls. Shirley and Alicante are both fairly good, though.

Even if you can find good tomato plants, looked after and kept warm in varieties you desire, they will cost you the earth, like as not.

So, many years ago, I took the decision to raise my own tomato, pepper and aubergine plants. I invested in an electric Vitopod Propagator with a thermostat (0845 602 3774 or see greenhousesensation.co.uk) and was able to raise my own with ease. It paid for itself within a couple of years.

I always try some new ones and this year I’ve opted for Orange Slice (Mr Fothergill’s) and Country Taste (Unwins). The rest are ones I grow every year, because I enjoy eating them.

They include the small orange Sungold, the stripy Tigerella, the red Vanessa and the large beefsteak Brandy Wine.

Seeds are sown in early March, pricked out into 3in (9cm) pots and then grown on in the propagator until they reach 6in to 8in in height.

All my tomatoes are cordons, grown under glass, and I allow them to set six trusses. The plant is pinched out at the top after those six trusses have set.

The only maintenance is regular feeding with tomato food between late May and August. The side shoots need pinching out (see picture) and they need water. However, when they first get planted in the greenhouse, in fresh soil, they are not overly watered for the first four weeks. I want them to put down good, deep roots.

We eat lots of them fresh, because they are full of vitamins A and C. We cook them, too, because then they offer more lypocene, a carotenoid thought to give some protection from certain cancers. Drizzling olive oil over fresh tomatoes is said to release more of it, too. It’s not really about keeping healthy, though; it’s the flavour of freshly-picked tomatoes that drives me on. We do get too many, but several years ago we also invested in an Italian passata machine, which produces sauce and most is frozen for winter use. (seedsofitaly.com or 0208 427 5020)

In recent years, there have been two developments. Many more tomato varieties can now be obtained online and those from Delfland Nurseries are organically raised. They sell lots of varieties, which arrive beautifully packed. (organicplants.co.uk or 01354 740553). They sell a range of vegetables throughout the year.

Some tomato plants (along with cucumbers, aubergines and peppers) are grafted and these plants avoid many soil-borne diseases.

Commercial growers use grafted plants primarily because crops are heavier and problems fewer. I found my grafted Shirley plants outdid my traditionally-raised ones. Delfland Nurseries also do heritage varieties, but I have found many of the American varieties need more warmth than I can give them. They are also selling blight-resistant tomatoes and these will do well outside in wet summers.

Ferline (red cordon) and Lizzano (a bushy red that tumbles) are both considered to be resistant. You will be very unlucky to get blight in your greenhouse, although do avoid making it too humid.

Most tomatoes have lots of seeds and these germinate if the inhibitor is stripped away. When I worked at Wellesbourne, in my lowly vegetable research post, we soaked the seeds. The same process takes place in the stomach and many a sewage farm produces pounds of tomatoes, although I'm not sure anyone picks them.

In fact, it’s thought that the seeds travelled from their South American home up to the United States in the stomachs of migrating turtles.