Greenhouse gardening enables the growing season for both flowers and vegetables to be extend. Many people use a greenhouse to raise plants from seeds which can not only be extremely satisfying but also a very cost effective way of producing plants.
Historically greenhouses have been made from glass; however, with new technologies polycarbonate has become a popular alternative. Polycarbonate is available in single, double and triple layers, the single layer is relatively inexpensive but has a tendency to blow away in high winds, double and triple polycarbonate sheets can be expensive, these are also more likely to become scratched, however, polycarbonate greenhouses are an excellent choice in place of glass.
To fully utilise a greenhouse it needs to be easy to move around in, staging or benching should be at a comfortable working height, with the back being easy to reach. The position of the greenhouse needs to be somewhere easy to get to and which receives the maximum amount of sunlight throughout the day and not shaded by overhanging trees.
Greenhouses will need to be heated during the winter months. There are many different heating options available from garden centres. A supply of electricity in the greenhouse will not only enable electric heaters to be used but can also provide the power for automatic ventilation and soil warming. Butane gas or paraffin heaters are excellent alternative form s of heating if there is no electricity supply; however, paraffin heaters can produce a lot of condensation and unless the wick is kept trimmed will smoke. Paraffin heaters should always be refilled outside of the greenhouse as any spilt paraffin will contaminate the soil and the fumes can be very harmful. The greenhouse should be kept at approximately 46 degrees Fahrenheit to grow plants during the winter, tropical plants will need a higher temperature.
Plants for greenhouse gardening will also require ventilation. Ready built greenhouses can with opening vents in the roof to release heat, there are also automatically controlled vents which can be fitted, the advantage of these is that the gardener does not have to be ‘on site’ all day to open and close vents as the temperature alters.
Shading will be needed when the sun is very strong otherwise leaves and fruit be scorched. Shading can be provided by covering the inside or the outside of the greenhouse or the south side of the greenhouse which has the most sun by cloths, netting or roller blinds which can be easily taken on and off or rolled up on dull days. White ‘paint on’ shading can be used on the outside of the greenhouse; however, this method of shading will reduce the light inside the greenhouse throughout the growing season.
One of the key factors in greenhouse gardening is maintaining hygiene, otherwise the plants and soils will become contaminated and disease in the greenhouse usually means unsuccessful and inedible crops.
Learn the secrets to growing a successful organic vegetable garden.
Posted on August 10th, 2008 by Jean-Helene
Filed under: Greenhouse Gardening
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 : http://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
Hi Katharine!
Wow, I love your idea of a Winter Greenhouse! Not only economical and ecological but effeciant too. It sounds like you have done an extensive amount of research and your plan looks great!
As for your questions…
Well compost is an excellent, and essentially free, source of heat. I think building a ‘chamber’ especially for the compest would be the best idea.
PVC is actually a fairly common material for greenhouse frames, and you may possibly be able to purchase one locally from a garden center or online.
I would imagine a pump would be the best way to circulate water through the heatsink, although this does increase costs.
Along with basic horticultural tasks you would need to maintain the supply of compost if you decied to use that, as well as maintaining the heatsink/pump. I can’t see too many additional tasks being required really!
The hinges would change depending on the materials used to construct your greenhouse. If you reverted to wood then doorhinges would be ideal. However as I like the idea of PVC, you could make a hinge and latch’ system by glueing two small PVC pipes together for the hinge, and then a tube cut in half for the latch, which the hinge would push into. If I’m not being too clear get back to me and I shall try to elaborate further or (try to) draw a diagram.
Wooden pallets with insulation would be far better suited than concerete. Personally you should stick with that idea
Well, PVC piping you might be able to pick up cheaply or even free if you asked around, especially if you’re friendly with any plumbers!! Compost you might possibly be making yourself already, and if not it’s really easy to start.
A half cylinder shape not only helps with air circulation but also looks great too. The only problem I can see it keeping it stored in your shed when not in use… as such a more conventionally made cubeoid shape.
Having never lived in the US I’m unable to recommend any retailers specifically, yet I’m sure if you went to a garden center nearby they might at least be able to point you in the right directions.
Hope this has helped!
I have a friend that thinks it is very easy to grow Roses in greenhouses,she is thinking something like 10′ X 16′.Would you please give me your professional opinon,thankyou,Tony Webb
Hi Tony,
Growing roses in a greenhouse is very much possible. It’s also not that difficult, especially for someone that is used to rose care.
It’s getting quite late in the year to start though, so if it’s something he or she wishes to start then it should be done as soon as possible.
Jean-Helene