Tomato, grow tomatoes

Solanum lycopersicum
The tomato is originally from Western South America where there still are several wild relatives, creeping, hirsute vines with small hard fruits. It spread north but it was not until it reached Mexico that cultivation of this plant was begun to greater extent. Here the large-fruited type we are used to was developed. The name tomato is of Aztec origin and the tomatoes the Aztecs grew in yellow, orange, white and red variants resemble those we have today. The great difference was that they were not self-fertilizing, but needed help by insects for their pollination. The self-pollinating tomato we are used to is an adaptation to the European continent with its fewer numbers of insects. The tomato arrived in Europe around 1540 where the Italians, chiefly, appreciated and developed this "˜golden apple"™ (pomo doro). Since then it has slowly but surely won its place as one of the most popular vegetables.
The tomato wants well fertilized soil, rich in phosphorus and humus, moisture retaining with a moderate pH-value, but too much nitrogen causes overgrown foliage and soft fruits which are affected by rot. Potatoes must not have been grown for the past 6 years in the same soil as tomatoes because of the risk of contagion. Tomatoes can be grown in the same place as long as they keep healthy.  They need heat and sun and thrive in sheltered places or green houses with cover on the ground when the soil has grown warm. Air the green house if the temperature rises above 30°C in it! The tomatoes could loose their flowers and the pollination could turn out badly. To ease the pollination you can shower or shake the plants during blooming.  
Tomatoes are rarely attacked by insects, but sometimes green flies or white fliers can cause problems in green houses. Fight them with repeated showers of teas of tansy, garlic or wormwood or pyrethrum and rotenone if the insects are really stubborn!  
Several fungi, bacteria and viruses are much greater threats to the tomatoes. Only plant sound, vigorous seedlings and plants and strengthen their powers of resistance with repeated showers of nettle water and extract of algae. Avoid close planting and burn all the parts of plants that have been attacked! It is a good idea to spray the tomatoes, chiefly those in green houses, once a week with water of skimmed milk or teas of garlic and/or peel of yellow onion to further hinder or fight attacks by insects.
Tomatoes thrive in the company of the onion family, parsley, basil, nasturtium and carrot but do not want potatoes, corn, the cabbage family or fennel in the vicinity.  
The tomatoes are usually divided up in forcing tomatoes for the green house and tomatoes for outdoors cultivation. The limits are fleeting and many sorts for outdoors planting can be grown successfully in green houses too. Typical forcing tomatoes, among which expensive hybrids dominate completely today, cannot handle the climate outdoors.

SOWING: Sow indoors just under 1 cm deep 7-8 weeks before setting out, in February-March for cool green houses and in March April for outdoors tomatoes! The best germination temperature is 22-26°C. Let the plants stand in a light airy place and after sprouting preferably at a temperature of 18°C. After getting a few real leaves the sprouts should be planted in pots. The temperature can now be lowered further. Temper the plants successively before setting out. Do not set the plants outdoors before the risk of nightly frost is over and the nightly temperature keeps above 7°C! Plant them a little deeper then they were in the pots and never allow them to dry out. Tomatoes get roots on the stems if they are allowed to get under the soil so overgrown plants can be planted lying with just the top above the earth. However, tomatoes which have been sown and set out too early often get disturbed while growing and that causes lanky plants and a bad crop of tomatoes. Do not hurry too much with your sowing if you do not have a really good "˜nursery"™.

SPACING: Tomatoes need a mutual distance of 35-55 cm.

HARVEST: Pick the tomatoes when they are fully ripe and warm from the sun! If there is risk of frost before all the tomatoes have ripened it is okay to let them after ripen indoors in a dark, cool (8-12°C) place. The whole de-leaved plant can also be hung upside down indoors and harvested gradually. Green tomatoes can be preserved or used for marmalade or fried.  Tomatoes can also be frozen in pieces like peppers and chillies, without parboiling for sauces and casseroles in the future.

SEEDS: 300-350 seeds/g, one portion yields 10-20 good seedlings for setting, about 5 g for 1000 seedlings.