Before much else, your community needs a functioning greenhouse. Are you many? Don't fret, fore the costs are very low indeed.
The most efficient shape is the dome. Cuts the area requiring heating by almost a third. In addition, the torus-harmonizing shape allows the air to circulate without fractionalizing much to reach corners, thus it is more apt at keeping the temperature at equal levels throughout the structure, giving the plants a predictable environment in which to reach for the sun.
If you can't find a food grade plastic in your budget range (PE), use wood for the structure. Some plastics contain pollutants such as lead (PVC) or disseminate other particulars that you generally don't want in your food.
If you have the cash; Polykeder is the latest and greatest of polycarbonate coverings. Vowes to contain up to 65-90% more radiation than conventional plastics. One of the only vendors charge 3000$ per 100m roll, with some meagre discount for even larger quantities. 1700$ for one half that.
As well as providing an additional source of foodstuff, a fish tank could serve a primary need of any greenhouse; Containing heat. A water tank is essential for hyperboreal strawberries, but anywhere you need to up the temperature, a black tank of water would be the first choice. If you don't want to clean after fishies all the time, put in some plants that feed of the nutrients in the fish leavings. Change water as often as you can and see fit, maybe twice or thrice every quarter (this varies according to the amount of organic matter in the tank.)
Strawberries, hemp, strawberries et.c.. Yeah. Plant what you want. In lush regions, you should be able to reach temperatures of 35C or 95F, even without nano materials.
Make a compost, why not? The tougher the food, the better the fertilizer. Mix in some cardboard for air channels and turn it regularly to speed up the process.
Dark soil is generally better.
Sea kelp conceivedly holds some astounding fertilizing properties.