Tomatoes are the most widely grown vegetable by the backyard gardener. There is a simple explanation for this. Commercially grown tomatoes are tasteless and since they are prolific croppers, produce a worthwhile harvest from a small area. Where conditions are warm enough, or in the green house, the tomato's close relative the capsicum is well worth growing. Not so much on the grounds of vastly improved flavour, but because of the appalling price asked for capsicums.
The commercial tomato grower starts his or her disservice by growing varieties that are tough. They must be able to take all the handling required between the producer and consumer. Secondly, the tomato is one bred to be prolific, rather than tasty. Third, they are picked green and ripened artificially. To add insult to all this, they are often grown with the system called hydroponics, which is guaranteed to remove any potential for flavour that the genes in the tomato originally had.
The backyard gardener takes the opposite approach. Through experience, and possibly by breeding, which is easy, the gardener selects for flavour. The tomatoes are grown with good humus compost, and allowed to ripen on the vine. Even where they need to be ripened indoors at the end of the season, they are superior in every way to the tasteless, odourless (ignoring the chemicals), monstrosities purveyed to an ignorant public.
Taking varieties first, it is important to distinguish between the hybrid and open-pollinated types. There are more varieties of tomato than any other vegetable so there is no need to purchase the hybrid types. They are more expensive, have a poorer germination rate, and are almost invariably inferior in flavour. There are two main sorts of tomatoes, determinate and indeterminate. The determinate are often called bush and the indeterminate, staking. The bush varieties require no pruning; the staking varieties are pruned to one to three leaders, depending on the vigour and fruit size. Left to grow indiscriminately, the fruit size will be small.
Pruning entails the removal of the laterals that grow from the junction between leaf and stem, as shown in the diagram. Some bush varieties will need staking, due to their size, but little if any pruning.
Tomatoes are best raised from seed at home. A warm, sunny window ledge and a few small pots are all that is required. Sow the seeds 6-8 weeks before you anticipate planting them out, about three to a pot. Thin the seedlings to the most vigorous plant. Do not be tempted to plant out any earlier than is normal for your district (ask your gardening neighbours). Tomatoes exposed to even brief bouts of cool weather will sulk and never be as productive as those planted out later. Frost will kill the plants. Before planting out, they must be hardened off. That is, exposed to increasing periods outdoors until, after about a fortnight, they are acclimatised to the vagaries of weather.
Unlike many other plants, tomatoes will benefit from being planted considerably deeper in the garden than they were in the pot. The stem will produce extra feeding roots and the increased depth will help reduce the plants' susceptibility to drought. The tomato also benefits from being slightly root-bound in the pot before planting out. The reason for this is that the plant responds to this condition by producing flowers, and hence fruit, much earlier.
Excessive levels of nitrogenous fertiliser will also delay the onset of fruiting, and consequent yield. Try to plant into soil high in humus from a previous crop and give copious side dressings of potash rich liquid fertiliser. Comfrey tea is the traditional brew. Fill a container with comfrey leaves, top up with water and leave to ferment in a warm place for a fortnight. Strain, dilute and sprinkle around your plants. The addition of a liquid seaweed preparation, such as 'Seasol' or 'Maxicrop' is also beneficial.
Some growers remove leaves from around the fruits in the mistaken belief that sunlight ripens them. It is heat that ripens; so do not get into this foolish habit that weakens the plant, reducing your harvest. You also run the risk of sun scorch on the fruit.
Tomatoes hate wet leaves, so water from below, if at all possible. In humid conditions, they will be subject to a variety of fungal diseases. Watering in the morning and occasional foliar sprays of liquid seaweed will help prevent these. Smokers should be banned from wherever tomatoes are grown. Tobacco mosaic virus is just as happy to invade tomatoes as the smokers' foul weed. Smokers who grow tomatoes should dip their fingers in milk, preferably 'raw' milk, before handling the plants.
The greenhouse white fly, a relative of aphis, can be a problem. There are now predatory wasps available that are specific feeders on them. Sticky traps of yellow card coated in gum can be made. They are attracted to the colour yellow and are trapped on the sticky gum. Pyrethrum is the last resort of the organic tomato grower.
The last of the tomato crop can be ripened indoors. Placing them on a warm, sunny windowsill is not as good as putting them in a drawer, individually wrapped in brown paper. Putting them in a paper bag with a ripe apple or banana can accelerate the ripening process. Ethylene gas, given off by all ripening fruit, is the ripening agent.
Culturally, capsicums' requirements are nearly identical to that of the tomato. They do require somewhat more heat to fruit. Capsicums are eaten before fully ripe, that is green, as well as when ripe, which can be red or yellow. The hotter capsicums, often called peppers, need a lot of heat to grow well. These are always eaten fully ripe. They can be threaded on strings and dried in an airy shed. A larger crop will be harvested when fruit is removed regularly before ripening. Plant them in rows 450-600 mm apart with 400 between plants.