Mini greenhouse for overwintering plants

[AnnaIkona]

Hello gardeners,
With summer ending in less than two months, I am beginning to think of ways I can enjoy gardening in the winter. And I thought of getting a greenhouse.

What do you think about it?
I was thinking of putting it on a layer of bricks so that they help it heat up inside. My goal temperature for it to be inside would be about 7°C (45°F) which I believe is the ideal temperature for overwintering fuschias? (Let me know if that's not true please)...the temperatures during the winter here in BC are about -3°C to 9°C (27°F - 48°F)...and I read that the temperature inside green houses are a couple degrees higher than outside so I think the greenhouse will be OK without heating?
Let me know your thoughts about that please!

~~and now a totally different idea~~

Is it possible to grow flowers in a greenhouse like that during the winter, if I heat it properly? Will they bloom? I don't know much about greenhouses but since they will be getting enough sunlight and will be getting enough warmth, they should bloom, right?
What heating methods do you think would be best for this?

Please let me know if you have any suggestions or can offer your advice thank you

[rainbowgardener]

To start with, if you are going to get one like that, look around for better price, you can get the same thing way cheaper:

https://www.walmart.com/ip/Best-Choice- ... 3=&veh=sem

I have one. I used it inside my unheated garage last winter. The garage is unheated, but keeps the greenhouse out of the wind. The garage does stay warmer than the outside. I used it with heat mats for the trays to sit on and fluorescent lights on 16 -18 hours a day. The heat mats were plenty of heat source for the greenhouse in those conditions.

https://www.amazon.com/dp/B01MA0JR17/re ... 8849873904

With two of those running inside the greenhouse inside the garage, I could keep temps in the 60's when the outdoor temp was down near freezing. One thing you need to watch out for is condensation. It isn't vented. With it all zipped up to hold heat in, I would come out in the morning and find it covered in water drops inside. So it is also keeping in a lot of humidity.

[imafan26]

I will be lucky to get anything planted in my garden the rest of the year. I did buy garlic and put them in the frig for October.

[applestar]

I don't know/think this will be good for overwintering because the temperature fluctuations will be too great. The plastic ones with wire shelves are not insulated, and note rainbowgardener used hers inside her garage.

I have used them to harden off tomato starts in spring outside.


They quickly heat up in the sun -- mine had a zippered vent at the top of the back panel as well as the full front zipper, and I needed to use the vent and front zipper to adjust the temperature. It needed to be closely monitored.

The one I have came with a shade cover to limit sunlight and a heavier black light excluding cover (which was described as useful for photo sensitive bloomers like poinsettia). When night temperatures were too cold, I used the shade and blackout covers -- sometimes together -- to help insulate, going out to cover just before or at sunset to hold in the warmth. When there was even more of a freeze, I covered on top of them with garden fleece.

In the morning, I had to go out at first light -- or as soon as the sunlight reached it to remove the covers and start monitoring temperatures.

I kept jugs of water on the bottom shelf to help weigh down the shelves and as thermal mass, but I also had to bungee it to stake behind it to keep it from falling over in strong winds. It fell over 2-3 times with all the plants inside before I figured it all out.

All in all, it was too much trouble for me.

[applestar]

Heating method -- if you have electrical outlet access, I think string of outdoor lights are pretty useful -- incandescent ones provide more heat but you would have to watch out that they are not too hot for the plastic cover.

Alternatively, use just one or two utility lights (usually available in automotive aisle) with a regular light bulb and adjust level of heat with wattage. CFL bulbs will heat too but I'm not sure if LED's do. Since this is being used as heat source, you would put it near the bottom, I think.

Definitely get max.min thermometer -- remote sensor with base station inside or you can get Bluetooth or WIFI - app connected ones now.

[ID jit]

If you are looking for "free" heat, you may want to look into several of the DIY solar furnaces. you can power them with little 12 volt DC fans, battery and a solar battery recharger.

If you go this route, I would suggest running the hot air into a series of tubes through a sand bed with pavers on top of it. This will function as a heat sink and help stabilize the temp. Down side is no sun = no heat, but they can put a serious dent in your electric bill if you are using electric heaters. After the initial construction cost in materials and labor, they just run. Odds are you will need some kind of thremostat / ventilation control to prevent over heating. You can also set them up to recycle to warm air which has cooled in the room.

Never heated a green house with one, nor tried for a narrow temp range with one, but I do know they will warm up an unheated garage.

[rainbowgardener]

Just running the heat mats inside it adds a LOT of heat, not just to the soil, but the air inside the greenhouse. But of course, you have to have electricity, which is another reason mine was inside the garage.

[AnnaIkona]

Thank you everyone for your replies!
I think that going with the heat mats would be the best heating method for me because I already have one, and it seams easy enough.
Is this method better for the over-wintering plants or my other flower idea? I think one heatmat should be enough for overwintering, but I think more would be needed if I want my flowers to bloom inside?

I am also thinking of just putting my overwintering plants in my shed (unheated). Do overwintering plants need sunlight when they are dormant? I don't think so. Maybe I will add a couple heat mats to the shed so that they don't freeze.