First, you need one tomato. Although, you might have to buy a small packet from your local food retailer first. If you are unsure about which type to get, go for the expensive, organic cherry tomatoes as they usually taste very nice. Select a very ripe, red tomato (but not decayed), cut it in half, take out about 10 seeds and plant them in a small tray with compost. Keep the compost moist and leave in a warm place on a window sill until they start growing. Once large enough to handle, place each seedling into an individual pot. By growing 10 seeds, you are increasing your chances of success. Once your tomato plants look strong enough to survive “your rough handling”, you can either throw out the unwanted tomato plants or give them away to family or friends.
Tip: Grow your seeds using a plastic meat or vegetable/fruit tray. Simply make a few holes at the bottom for drainage.
Tip: when re-potting into a single pot, use a 150 ml cream or yoghurt pot with a couple of holes at the bottom too. Or use half an empty loo roll. I roughly line it with a little piece of kitchen roll to give the bottom some support and prevent the compost from falling off.
Good luck for your planting!