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
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
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) 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
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
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.
Tomato plants are self fertile and will generally pollinate
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.
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