BCSS - Forum

Dear friends, I am already running late on my project of building a more efficient greenhouse. During the last winter, my electricity bills were higher than ever, so I have decided to redesign it, but I need assistance from more experiences cacti growers.



This is what I planned. It is 25 cm below ground as that is the frost line (frost depth) in my hometown. Above the concrete foundation is the autoclaved aerated concrete (AAC) as I won't be keeeping plants below. Bottom shelves are for storig gardening equipments. And the next is where I kindly ask for assistance what will capture heat the best.

For side panels I was thinking of thermal insulating glass (thickness 4+16 argon+4), but I am unsure.

For roofing I was thinking of 16mm polycarbonate sheets. I can find a single grower that used acrylic sheets.

Any comments and ideas are more than welcome!

Dwarf wall, well insulated. Double glazed panels on sides. polycarbonate on roof. Consider the North wall to be insulated to the eaves. Insulation in ground On perimeter of the greenhouse.
Timber structure. That would be my choice if I built my new greenhouse.

Perhaps think a lot more about your interior ... It needs to be for you as well as plants! You will need an area where you (& visitors?) can sit and do things, rather than have shelving throughout!

More importantly, think about heating and cooling. Both will need a good internal flow of air. So lots of vents for summer cooling. For winter heating, there should be a gap between your plant-staging and the greenhouse sides.

This suggests making the whole greenhouse wider if possible. Look at photos of other people's greenhouses and copy one you like. Draw and plan all the details down to a parts list before you start any of it.

Hope this helps,
Best wishes,
Derek Tribble

I agree that you need somewhere to just sit, look at your plants, have a glass, or 2, of something nice & just chill. I don’t know about you but I can spend hours in my greenhouse just picking up various plants, giving them a good once over, removing any debris, using a magnifying glass with Lithops which are fascinating to examine in detail or checking my books. It’s good for the soul & very calming in these uncertain times. Enjoy

What about adding thermal mass, such as black barrels of water along the north wall?

Two comments:

You need plenty of ventilation, especially if you do not have doors at both ends. It will get hot even with a LOT of vents.

When I built my greenhouse, the supplier asked if I wanted a regular one or an extra height one. I commented that an extra height one would be a lot more expensive to heat in winter (and I dont grow tall plants anyway), but I was told that some large proportion of the heat is lost through the roof (85%?) so making the sides 4m high instead of 3m high would not make as large a difference as you might think. So (i) does part burying it give as much advantage as you hope? Try asking others who have such a design, and (ii) you should probably concentrate your insulation efforts on the roof.