Val Bourne is ready to start sowing her crop for tomatoes, sweet peppers and aubergines

The light levels have been so low that I haven’t begun to sow any seeds as yet, but now I must get busy. The first things to go in will be the tender vegetable crops for the greenhouses, such as tomatoes, sweet peppers and aubergines.

I used to buy ready-grown plants once, but they became really expensive and the choice of varieties was so limited. Worse still, the plants were often blackened by cool temperatures, so I invested in my own Vitopod electric propagator and this made it extremely easy to produce my own plants.

I can now grow the varieties I love in sufficient quantity and I’ve worked out that my Vitopod propagator has already paid for itself a couple of times over (from Greenhouse Sensation — www.greenhousesensation.co.uk/0845 602 3774).

My preferred tomato varieties are all grown in the greenhouse because we’re simply too cold for outdoor varieties here. The bush varieties take up too much ground space, so I stick to growing upright cordons that produce roughly six trusses.

As the side shoots appear in the leaf axils they are pinched out. I do grow traditional varieties such as ‘Shirley’. This round red F1 hybrid fruits earlier than most, producing reasonably flavourful fruit. ‘Alicante’ (also commonly available) has a similar flavour, but the fruit is thinner-skinned and a brighter red.

Both still hold AGMs (the Award of Garden Merit) from the RHS and these awards have been reconfirmed by a new trial held in 2011. ‘Shirley’ is also available as a grafted plant and these are more disease-resistant to soil-borne diseases, more vigorous than seed-raised plants so they fruit earlier. Marshalls Seeds 3 grafted Shirley plants for £10.95 (www.marshalls-seeds.co.uk/0844 557 6700). We generally have six or seven varieties and the red-skinned ‘Vanessa’ (also an AGM) was the Best Beloved’s favourite last year for flavour, texture and yield. This variety (available from King’s Seeds — www.kingseeds.com/01376 570 000) can be vine ripened and this seed company offer good value.

Cherry tomatoes are highly popular, especially with the grandchildren, and they have a good flavour. ‘Sungold’ (also AGM) has about 20 small orange fruits per truss with a Brix sweetness rating of 9.3, much higher than most.

‘Sun Baby’ (also an AGM) produces bright yellow, perfectly round fruits with a balance of sweetness and acidity. One truss can carry over 50 fruits.We always grow a Beefsteak tomato, and ‘Marmande’ produce large fleshy fruits that are perfect to cook, or for making passata. Seeds of Italy (www.seedsofitaly.com/0208 427 5020) supply an excellent passata machine and passata freezes well.

I always try to find room for a plum tomato and ‘Sweet Olive’ (another AGM) fruits early and this vigorous tomato yields well providing tasty, rounded red plum tomatoes.

The seeds are sown in three inch pots of seed sowing compost and then pricked out when they have developed their first true seed leaves. The technique is to handle the leaves gently. Never grip the stems. Pot into three inch pots individually, using John Innes 1. As the seedlings fill the pots, repot them again using John Innes 3. The numbers refer to the amount of fertiliser and 3 contains the most food, 1 the least. We adopt the same seed sowing method for aubergines and sweet peppers, and the sweet peppers freeze well for winter stews and casseroles.

The plants should not be put into the ground in unheated greenhouses until the middle of May at the earliest, unless you have a heater.

If your garden is cold wait until the first week of June. Stake the plants and water them every day with a can of water.

Mornings are best. Once the first flower truss has set, begin to feed your tomatoes every two weeks, either with liquid tomato food or with home-made comfrey tea.

The Gardener’s World website will explains how. It’s smelly to make, but entirely free and we make loads of it for all out ornamental tubs and greenhouse plants (www.gardenersworld.com/how-to/projects/basics/how-to-make-a-comfrey-feed/200.html).