Tomato Cultivation Tips

Storage of Seeds from Ready to Grow
If you aren't going to sow your new tomato seeds for a while they can be stored for several months, sealed in their packaging in a cool, dry, dark place, or in the top of a fridge. Never store them in a freezer as the sudden temperature drop is likely to kill them.

Sowing Tomato Seeds
Aim to sow Tomato seeds from January (if you can supply sufficient heat and light) to April, although you can sow faster maturing varieties in May. On average it takes 6 to 7 weeks from sowing to reaching a final transplant size.

Sow the seeds on top of a good quality seed or general purpose compost and cover with about 1cm of fine compost or vermiculite. They can be sown in reasonably deep seed trays, straight into individual 3 inch pots (2 per pot - remove the weaker seedling) or into rootrainers. Keep the compost just moist - don't let the top of the compost dry out too much, as this is a common cause of germination failure. Cut down on watering by covering the pot or tray with plastic film. If you have a heated propagator use a temperature of 18C. You will need a minimum temperature of 16C for successful germination. They will germinate well in a warm room. Don't leave the seeds in direct sunlight as the heat generated may kill them. If you like you could also spray the surface with a dilute copper-based fungicide (which is acceptable to most organic gardeners).

Watering
Once they have sprouted, water the tomato seedlings regularly, but don't let them become waterlogged as this encourages rot. Don't let seedlings dry out as they rarely recover at this stage.

Larger plants should be watered regularly allow the top cm or so to dry out in between watering. Once fruit has started to set adequate moisture is essential. Dry periods significantly increase the risk of fruit splitting. A steady supply of moisture produces the best quality, best flavoured crops (I use a low-cost automatic watering device that fits on a bottle to provide a temperature sensitive water supply - available in our Accessories section) Apply a mulch around the plants to reduce water loss. The best time to water plants is in the morning.

Potting On Your Tomato Seedlings
When the tomatoes have produced their first pair of proper leaves they can be potted on into individual 3 or 4-inch pots if grown in a seed tray. Use good quality potting compost and mix in some organic slow release fertiliser, according to the manufacturer's instructions. I use 2 parts peat free compost, 1 part coir (a peat substitute), plus a little additional organic fertiliser.

Pot the tomato on again before it becomes root-bound (you'll see roots appearing through the holes in the bottom of the small pots) The final size of pot required will depend on the variety grown and how big it gets! Seedlings should be grown in good light.

Adult tomato plants need lots of light. Place pots on warm sunny windowsills, in a conservatory or in a greenhouse.

Planting out Tomatoes - Soil Preparation
In a rotation tomatoes rotate with potatoes, peppers and chillies. If planting outside or directly in greenhouse border prepare the soil in advance by digging in plenty of organic matter (preferably a month or so before hand). Garden compost or well rotted manure are equally good. The idea is to increase the moisture retention of the soil rather than create high fertility (high Nitrogen content would create too much leafy growth at the expense of fruit).

Planting Out Tomatoes - Position
Tomatoes prefer a spot in full sun and plenty of moisture (but hate being waterlogged). Tomatoes can be planted out after the last frost (May/June). Make sure that the variety is suitable for outdoor cultivation as some varieties are very disappointing outdoors in the UK. Make sure that plants have been allowed to acclimatise to outdoor conditions for 2-3 weeks before they are moved permanently outside. During this time gradually increase the amount of wind, sunshine and cooler temperatures that the plant experiences.

Tomatoes in Pots
Tomatoes can be grown in grow bags (although they do tend to dry out quickly) or in large pots (preferred).

Feeding Tomato Plants
After the first flowers appear, potted tomatoes should be fed every one or two weeks with a organic liquid tomato feed. Tomato fertilisers are high in Potash, which is essential for fruit development. Tomatoes in the ground may not need feeding.

You could add some Seaweed extract (without added fertiliser) to the water once a week. This toughens them up a little and improves disease resistance.

Pruning and Training Tomatoes
Determinate (bush) tomatoes require no pruning and no particular training - if harvests are heavy put a few stakes in and tie any overburdened shoots to the stake with soft twine. Limit the number of trusses to 6 or 7 for the best quality fruit.

Indeterminate (cordon) types are pruned by pinching out the side shoots (the shoots that grow out from between the stem and leaf joint) by hand as they develop. This keeps the plants energy concentrated on flowering and fruiting rather than producing leafy growth. They should be planted next to a tall stake (4 to 6ft). As the tomato grows the stem be trained around the stake and gently tied to it with soft twine. Leave some slack as you tie in to allow the stem to develop. Once 6 or 7 trusses have been formed, stop the plant by breaking off the growing tip.

With both kinds, remove any yellowing or unhealthy looking leaves from plants as soon as they are spotted to reduce the likelihood of disease entering the plants.

Pollination
Tomato plants are self fertile and will generally pollinate themselves.

Harvesting Tomatoes
Harvest tomatoes as soon as they are ripe and eat as soon as you can ... mmm you won't want to wait! Prompt removal of fruit encourages others to ripen. Frost will destroy fruit so harvest all tomatoes before the first frost and ripen on a windowsill, or if pot grown (and if you have room) bring the plant indoors to finish ripening.

Common Pests
Aphids are the prime suspect as they are rather fond of tomato leaves and can be a problem in greenhouses in particular. To get rid of them gently rub them off by hand. There are biological controls available for use outdoors and in the greenhouse (see the links page for suppliers). Some people use chemical aphid sprays but I have found most to be ineffective, as over-use has led to widespread resistance. I have had some success with a new organic product called Eradicoat, which suffocates them (see links for suppliers).

Whitefly can be a serious greenhouse pest, biological controls are available and yellow sticky traps attract and catch them.

Occasionally red spider mites can be a problem if there is low humidity. Spray the leaves of your tomato plant with water to increase local humidity, spray the undersides with Eradicoat or try biological controls.