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need ideas on greenhouse

Hi there,

I live in Boston, MA and I am looking for some advice on Greenhouse construction for winter gardening only (and vegetables that are appropriate for that as well). I am looking to build a greenhouse that I can put up in the fall and take down in the spring for growing a winter garden. It will have to be able to be taken apart into its components and stored in a shed in summer months since my family has no need for it then. Due to the fact that it will be used in the winter, it will have to be highly insulated and have a heat sink that will be able to help maintain a constant growing temperature for the plants inside. Ideally I would like to avoid expending much energy heating the greenhouse. I am, of course, also doing this on a budget. Here is what I have come up with so far.

1. I will use triple-wall or 5 wall polycarbonate panels for the walls of the greenhouse
2. I have found a few insulating products that look like they could be useful
3. I am thinking of using a solar collector water heater as part of the heat sink- easy to construct on my own : https://www.instructables.com/id/Solar-Thermal-Water-Heater-For-Less-Than-Five-Doll/ that could circulate hot water into the heat sink
4. I am learning about heat sinks and thinking that I want to use the simplest design and organic materials (mud, rocks, or water) to hold the heat during the day and release it at night.
5. The greenhouse footprint can’t be larger than 8’ x 10’
6. I prefer the simplest construction that meets my needs (and the easiest to put up and take down)

Questions that I have:
1. What are the possibilities for using compost as a source of heat?
2. What about a PVC frame?
3. How would I circulate hot water through the heat sink?
4. What are methods to reduce daily management of the project?
5. Types of hinges to use?
6. What type of material should I place the greenhouse on?- it will be sited on the concrete area around our swimming pool and I don’t know what sort of insulation is necessary after that. I had the idea of wood pallets with insulation inside them but that may not be enough at all.
7. Any ideas of ways to re-use materials to do this cheaply and reduce waste?
8. Any suggestions on the optimal shape of the greenhouse roof/sides to increase heat retention and circulation of warmer air.
9. Any suggestions of retailers that might have the materials that I am looking for.

Some links that have been useful so far:
http://attra.ncat.org/attra-pub/solar-gh.html#storage
http://growerssupply.com/farm/supplies/cat1;gs1_greenhouse_building_materials;gs1_corrugated_sheets_panels.html

Goodhart8 years ago
1. What are the possibilities for using compost as a source of heat?

Some "manures" are "hot (horse manure, for instance)", that is they compost fairly quickly and will heat up. The biggest problem is control: temp., humidity, direct sunlight; in order to control the amount composted in a particular time period. It tends to "get hot", remain hot for a bit (depending on the amount of "fuel" you have) and either burn out, or in some cases, burn up (I have seen piles of grass or leaves, that had a wet or damp center, burst into flames outside). There may be a way to do it, so don't let me discourage you.....I am just relating my past experiences. :-)
There's really quite fragrant type of chipping that's like peat and bark combined in texture, in small piles, less than 20 feet wide it will make large amounts of heat with relatively low risk but when you a 200 foot pile of it about 40 feet high it needs to be shifted a lot and has a habit of catching light eventually... I'm not sure of the name but they always had a big pile in the harbour because it was shipped through, you could fill a cardboard box with it and make a nice warm seat for a month or so, granted the cardboard went to bits as it steams a lot.