Growing Tomatoes In A Cool Greenhouse
If you are in a cool climate, Then you need a greenhouse to ensure a good crop of tomatoes. Growing tomatoes in a cool greenhouse is really very straightforward. You can either start with plants bought from your local garden centre or grow them from seed.
If you are growing them from seed, then You will need to start sowing your seed early, probably before the last frosts are over and the best way to do this is to sow them indoors. I usually sow in 3″ pots – 3 seeds to a pot and place on a well lit and warm windowsill.
Make sure that they do not dry out. Once the plants begin to show, and when there is no risk of frost, transfer the pots to the greenhouse. Grow them on until the plants are well established in the pots, but before the roots begin to circle in the pot. The soil should be retained by the roots and a god network of root show. If you leave them too long in the 3″ pots, they will become root-bound, and will take much longer to re-establish ehen transplanted. You should then separate the three plants and re-pot each one into a 5″ pot. Grow on like this until they are ready to be potted on again. Now you need to decide how and where you are going to grow them. If you decide to grow them in growbags, then they should be planted no more than three to a grow bag. However, I have found that they grow rather better in deeper pots than a grow bag. One successful technique is to cut a growbag in half and stand each half on end, with one plant in each. This will give you a much deeper root run. I usually now grow my tomatoes in large pots in a good homemade compost.
As you put your plants into their permanent position, consider supports for them. They will want good support up to the roof of your greenhouse. A good way of doing this is to tie a 6ft bamboo cane to the roof of your greenhouse and put it into the pot as you plant your tomatoes.The plants will become very heavy when laded with fruit so canes will need to be supported from the roof of the greenhouse
Tie the plants to the canes as they grow. The sideshoots that grow from the leaf joints should be regularly removed while they are still small. Watch them gro and produce fruit, keeping them always watered. Don't let them dry out, and keep the watering consistent. Uneven watering can cause greenback – which makes the fruit go black at the bottom and makes them inedible. If this happens, pick the infected fruit off and make sure the plant it watered correctly. They should recover. Tomatoes need about 1 litre (2 pts) of water a day, although cherry tomatoes such as gardeners delight only need 1.5 litres (3 pts) of water a week.This makes the fruit taste sweeter.
It is advisable to maintain humid conditions when the flowers appear by spraying the plants daily. You should also gently shake the plant to move the pollen about. Remove all the leaves below the lowest fruiting truss. This will give the plant more air and light so the fruit will ripen faster. At this point start feeding with liquid seaweed. (Tomato feed purchased from garden centre is equally good.). Some people also feed epsom salts because they say that it makes the tomatoes ripen earlier.This has not been proven, and is in any case unnecessary in a diy cool greenhouse.
Pick the fruit regularly, that way you get the sweetest flavour and picking encourage the production of more fruit.
Tomatoes are one of the easiest greenhouse crops and are very rewarding, reliably giving a heavier crop of ripe clean and healthy tomatoes than you could grow outside.
