I have 2 mini greenhouses in my back garden, 1 is a large walk in that I got from argos for 30 quid shelving included, and I bought a small parafin heater from ebay for a tenner, the greenhouse has been out since last august and has withstood all the bad wind and rain etc... And I have successfully grown apx 95 chilli plants, 40 sweet peppers and various bedding plants all from see. the heater keeps it at an average temp of 10deg through the night even with hard frosts and between15 and 25 deg daytime. my smaller 4 tier mini pvc greenhouse which cost 15 quid from my local garden centre and is heataed with a hurricane lamp for about a tenner is also succesfully growing numerous flower seeds. So it just goes to show that even on a budget you can grow things succeswfully!!!

