It’s quite difficult to decide where to start when you have decided to grow you own do you:-

Go along to your local garden centre and pick up ready grown plug plants (these are plants which have been grown commercially and usually have been grown early so when you pick them up you need to keep them inside for a while)

Or grow your own from seeds – you get a much greater choice If I’m honest the first time I grew them I bought mine, you can pick them up from car boot sales village halls or garden fetes quite cheaply as everyone I know always grow too many from seed and so have surplus to get rid of, May is a good month to pick them up. It is also a great way to buy different types so you can grow a selection. Look for sturdy plants with several ‘branches’ and dark green leaves; reject any which have yellowing leaves or dried out compost.
The tomatoes can be planted outside when all danger of frost has passed this can be mid may in UK or even as late as the beginning of June. Plants bought before this time will need to be kept in a sunny frost free area until the frosts have passed without too much of a fluctuating temperature.

If you want to grow them form seed you need to collect some bits together

Seeds: sounds obvious but might be a good idea to start off with a reliable good cropping tomato like Gardeners delight – seeds can be Sown in mid-March for outdoor crops, and mid-February for growing in an unheated greenhouse.   

Compost: This can be purchased from either your garden centre or DIY stores. I would suggest you buy one which is specifically for growing seeds and seedlings – this is because the other more basic compost don’t contain the quite the right growing nutrients for seedlings, however you can use all round compost  although they may take a little longer to germinate.

Seed Tray or Pots: You can buy these again from garden centres or DIY stores they can be reused so can be an investment.

Propagator: You don’t need to buy one of these if you are on a budget or just trying this out for a first time – You can use Yoghurt pots for the seedlings to grow in with plastic bags secured around the top -. A propagator acts like a mini greenhouse maintaining high levels of humidity around the young plants.  If you intend taking this on as a hobby it is good to invest in one or if you are like me I have loads now!  You can buy electric ones which keep your seedlings at a constant temperature which is great for them as they develop quicker. Or you can pop your pots on a light window sill (as long as you have double glazing) they don’t like the cold – like me! They don’t like huge changes in temperature so don’t make it too sunny a windowsill or they may well get too hot then too cold.

 Hydroponic Unit: Now these are quite expensive and unless you are intending going into this on a regular basis not necessary. However, I think once you have bought one of these you would be amazed at the results.  These units do not use soil and an astonishing amount of fruit and vegetables can and are grown in them – more on a commercial basis.  But if you have a greenhouse with an electrical supply or indeed a garage with a window you could set this up and have bountiful crops. It is reusable and in depending on the unit you can grow up to five plants in it.
The concept is that the mineral solution provides the nutritional needs of the plant. Almost all plants can grow without soil as long as a nutrient based solution is present. The solution is actually formulated to meet the demands of a thriving and growing plant and given to the plant in regulated doses. You can set it up so you can go away on holiday for two weeks and it will water itself, you return to a huge yummy crop of ripe tomatoes.

Pots : You will need a couple of pots in different sizes so that as your plant grows you can pot them up. The largest final growing pot will need to be about 10- 12 inches/ 30 centimetres across the top.  You can use an all purpose  compost when potting up, although you can use specialised brand name compost which can have balanced nutrition and/ or water retaining qualities, the choice is yours. If you have taken advantage of councils giving away reasonably priced compost bins you may well have your own compost to use.

Grow bags: Are a wonderful invention for anyone starting out growing your own produce. They are a container and have balanced compost all in one packet, who could ask for more.  I personally think these are great for growing your own toms in, I put usually two in a bag so they aren’t fighting for nutrients but you can put three especially if you use bottomless pots which go into the grow bag it gives the plants more root room .