If you are growing tomatoes this year and you want to add some exotic-sounding types to your menu — doing your bit for preservation at the same time — a host of endangered tomato varieties are being championed in a new campaign.

Whippersnapper, Tiger Tom and Ryder's Midday Sun are some of the endangered tomato varieties being promoted in the Dig Your Dinner campaign, an initiative by Seeds of Change, which has teamed up with organic growing charity, Garden Organic, to raise awareness of the benefits of diversity in variety.

Research shows that only 9 per cent of gardeners experiment with growing different varieties, but you can do your bit to help save ten endangered tomato varieties for future generations if you join in the campaign, to be launched on March 31 and supported by celebrity gardener Rachel de Thame.

Varieties, such as the small plum variety Auntie Madge's, Broad Ripple Yellow Currant, which produces masses of sweet-tasting, tiny yellow fruit up to mid-November and the mild Pink Cherry, are available through Garden Organic's Heritage Seed Library, which holds a collection of more than 800 endangered vegetable varieties facing extinction.

“All the tomatoes have great flavour, are easy to grow whether on a windowsill, in a patio pot or vegetable plot, and are part of our British heritage which we should treasure and protect for future generations," Rachel de Thame says.

She offers the following tips: 1. Start small if you are a beginner. If you have limited space grow some tomatoes in a pot.

2. Try out some endangered varieties which have proved reliable, such as My Girl, which has medium to large, plumshaped fruits with few seeds, Kenilworth, a classic round, red sumptuous tomato with a sweet and herby flavour, or the early Whippersnapper, which produces an abundance of attractive, small, oval, pinkish-red fruits and is ideal for tubs and hanging baskets.

If you can't get these, heirloom varieties (available in various gardening outlets and online) such as Red Beefsteak and Red Cherry are also easy to grow.

3. Spring is the time to sow your seeds. They are not hardy, so start them off inside — a greenhouse, or windowsill will do perfectly. Sow your seeds into a seed tray which has been filled with good quality seed compost, firmed gently and watered. Try recycling containers like yogurt pots, washing them thoroughly and punching a few holes in the base for drainage. Drop just one or two seeds on the surface of the compost in each module — this avoids wastage but allows for the possibility that one may not be viable — then cover with a thin layer of compost or vermiculite and label.

4. Once they start to grow, they will need to be re-potted into larger containers to allow space for the rapidly developing root system. Keep moist and when the risk of late frosts has passed and the first flowers have appeared — usually some time in May — help the young plants to acclimatise gradually to outdoor conditions by popping them outside during the day and bringing them in again in the evenings. After a few days they should be fine to be transferred to their final growing position. Secure the main stem to a sturdy cane and keep them well-fed and watered during the growing season.

5. Keeping the soil healthy is at the core of successful gardening, so continually feed and improve your soil quality and structure by adding copious amounts of home-made compost.

6. Tomatoes can often be affected by whitefly. To combat this organically be vigilant and look out for the eggs on the underside of the leaves, spraying them off with a blast of the hose or wiping thoroughly by hand. Greenfly (aphids) are also common and can be swept away with thumb and forefinger.

7. Ladybirds feast on aphids, so encouraging them into your garden will also help to control them. Flowers such as calendula, fennel, Californian poppy and poached egg plant tempt other predatory, pest-controlling insects, including hoverflies and lacewings.

■ To obtain the endangered seeds you need to be a member of Garden Organic (gardenorganic.org.uk)

■ For more information on the campaign and how to get involved visit www.digyourdinner.co.uk