Start most tomatoes under glass in July/August.
Sow the seeds shalowly into seed trays using a well drained and light seed raising mix.
Keep warm and humid until seeds germinate.
The temperature can then be gradually reduced but must not fall below 10°C.
"Tiny Tim" can be started later (after last frost) if you are not able to sow under glass.
When seedlings have 2-3 true leaves, prick them out and put each seedling into a 10cm pot.
Keep seedlings well watered and feed with a moderate nitrogen, high phosphate fertilizer.
I normally use a blood and bone and a little super phosphate incorporated into the potting mix and supplement with standard rate liquid fertilizer, such as phostrogen.
Pot on to larger containers as required.
Plant in the garden only after all danger of frost has passed and the night time minimum temperature is higher than 9°C.
Dwarf tomatoes can be kept in containers.
Traditionally tomatoes are trained to one leader, but for home cultivation, it is OK to keep 2-3 leaders per plant, as long as the leaders are well staked and the plant well fed.
Grafted tomatoes can have 10-20 leaders!
Dwarf tomatoes should be allowed to branch naturally and normally do not need staking.
Around September switch to a high potassium fertilizer, eg. proprietary tomato fertilizers, to encourage flowering.
Follow the manufacturer's recommendations.
Start out by feeding at quarter strength until the second flower truss, then gradually work up to full strength.
Stop feeding when the leader shoot has reached the top of the support structure.
It takes heat to ripen tomatoes, so in late Autumn, pick all unripe tomatoes and store in a warm place out of direct sunlight.
Alternatively use them to make fried green tomato.
Footnote: In-determinate tomatoes are those where the leaders will grow to an indefinite length if you allow them.
Determinate tomatoes will terminate growth once a certain length is reached.