Posted: 08/07/2015 at 12:40
If you are just starting out you can buy portable greenhouses for about £20 from garden centres that will fill your 2 x 1m space. More permanent greenhouses for a size 4 foot x 6 foot can start from £500, in these you can have a portable heater. Not advised in the £20 ones though.
To help with snails, try putting crushed egg shells around your plants. Slug and snails don't like going over them. Hope this helps