Once you've got your greenhouse ready, it can be difficult to know exactly what to grow. All sorts of things will grow in a greenhouse, and most will grow at least a little better than they would outside it, but there isn't much point in doing all that work just to end up with a crop of slightly bigger potatoes.

The two things that most people grow in greenhouses are tomatoes and cucumbers, as they grow quite badly outside but very well inside. They are also easy to grow, as the seeds available are of such high quality: often you will be able to grow quite good tomatoes and cucumbers even if you're too useless at gardening to even follow the instructions on the seed packet properly.

After a while, though, this gets dull. So what should you do next? The answer is that you should get a little more adventurous with what you grow in your greenhouse. Strawberries are a good start, as they are very nice, expensive in shops, but not too difficult to grow yourself. Other bush fruits such as raspberries and blackcurrants also work well in a greenhouse.

Once you're a greenhouse pro, though, the hardest thing to try is a melon. There's a reason why farmers have competitions to see who can grow the biggest melon: melon-growing is more of an art than a science, and it's very difficult to master. Generally, the key is to give your melons as much support as you can: as soon as the plant starts growing, support it with a length of string tied to the roof of your greenhouse, and once melons start to appear, support them with string nets. One other thing to be aware of is that it is easy to accidentally drown melons if you water them normally, so you should set up an alternative system, such as a pipe leading directly to the plant's roots.