Greenhouse Growing

Hello, I am thinking of moving my inside cactus collection to a greenhouse in my backyard. It gets fairly good sunlight throughout the day but I am concerend about the NY winters (Long Island to be specific). I really can't afford to heat it with gas or electric so I was wondering if anyone knows of material that could be used for roofing and walls that is insulating and cost effective.

Thanks in advance.

Try looking into bubbleglaze products or large cell bubble. This type of insulation is very cost effective. The bubbles trap heated air while letting light come through. It is reminiscent of packing bubble wrap- but IS NOT the same. This type of insulation should last three to four seasons. Work it in vertical strips between supports. Another thing you should consider is using silver reflective foil on the north facing wall of your greenhouse. This reduces heat loss and since it doesn't get direct sunlight you don't have to worry about overheating your plants. You'll want to install the foil horizontally attatching each strip to the next with clear sticy tape to stop heat loss through the lining.

Not walls or ceiling- but a ground of gravel can help retain heat as it collects heat from the day and slowly expells it throughout the night.