I bought a 6×12 greenhouse and I have been trying to find more ways to keep it warm overnight. So far, I have two 55 gallon jugs for thermal heat, and I am looking to get a third, but what are other ways to keep it warm overnight for the winter months?
My next issue is that I just went out to see my plants because it was going to be below freezing and I saw my palm has sun spots after just a day or two. What is the best way to help with this? I am thinking of putting up temporary cardboard to create more shade in the greenhouse so the plants are not in direct sunlight. Ideas?
by Big_Ability5052
14 Comments
You need a huge amount of thermal mass to use thermal mass. Try having 5 or 6 barrels of water, and it will work much better. It only does so much though. I also have an electric heater.
Lots of rock and stone for the floor! Like others mentioned thermal mass. Also, if the containers of water can be painted black they can pick up some more heat absorption
Despite what the internet says (depending on where you live of course) adding water and rocks won’t help keep your greenhouse warm at night.
The easiest and most reliable way is a small heater.
My guess is that the palm went from indoor into the greenhouse. If that’s the case, you should slowly acclimate the plant to the sun much like you do when putting seedlings into the garden in the spring.
you should insulate the north side of it (sun’s not really coming in from that way) – maybe blankets on the outside, or stacking strawbales
Insulate the walls, especially the entire north side, with some foam board insulation. Get the highest R-value you can find/afford.
With enough water, thermal mass helps take the edge off, but it requires quite a lot. It also requires sunny days every day. You will struggle overnight with this setup after a cloudy or snowy day.
I would definitely get a heater as well. Winter is just getting started, and I’m sure you haven’t even gotten the coldest part of if yet.
You have to acclimate your plants to the greenhouse, especially if they’ve been indoors. Take them out for a couple hours for 2-3 days and then they should do better. Increase the time over a week for best results.
I’ve done a few posts about my greenhouse heater. Great results and doesn’t need power. Just the canned heat. It’s called the VESTA portable heater and stove
https://preview.redd.it/gkxe60fbdp0e1.jpeg?width=3024&format=pjpg&auto=webp&s=655a910ea825983ff3456ff61086e5c6b821eba4
There’s 2 main parts to the formula of keeping a space heated. Heat storage capacity and heat loss. Right now you’re trying to fill a flat tire that has a huge hole in it. First fix the “leak” literally and metaphorically. Work on reducing heat loss first as it will give you the most benefit for least amount of work. Is that single or double layer polycarbonate? Single has an insulation rating of only R1. If you can increase it to R2, you’ve just cut your heat loss in half! A 100% gain in efficiency. Seal gaps, cover with a tarp at night, insulate the north wall and possibly east and west sides as well.
These greenhouses are just not designed for winter. I’ve been studying winter greenhouse design for years and you really would need to start from scratch to make it right. You can gain a few weeks season extension with tricks but don’t waste your money on a heater. Just buy grow lights for inside your house.
Just shade half the green house and acclimate the indoor plants to the sun.. looks like sun spots on the leafs.
I would start with strategic watering. Spray and pray doesn’t work when the sun is involved. You’ve got a powerhouse in that greenhouse some would say. As soon as the plants hit the house, water dirt – not plants.
Obviously there are plants that love the misting but even they shouldn’t have direct sun while wet.
Try watering with a contractor fabric between the plants and the sun. When the greens dry off, you can remove the shade and let them go full Monty.
If you just recently moved stuff out there, the sun spots might just be them adjusting. You could also hang some shade cloth inside the greenhouse. If it’s inside it won’t block heat but it will provide some sun protection for the plants.
I’ve been thinking about how best to insulate as well. Does anyone know if a foam floor or something would help or hurt? I’m thinking it might cause less cold seepage from the earth, but it also might prevent any warmth seepage from it as well.
I have a 6×6 greenhouse in zone 6a. I’m overwintering my Bonsai in it. If my target temp range is between 28°F and 50°F, is a space heater and an exhaust fan the best/only option? I’m currently waiting on a 600CFM exhaust fan, and considering a small, cheap space heater fan. I just don’t know when enough is enough.
Based on the condescension in the 1st pic, there’s a good chance that droplets fell on the palm in the 2nd pic, acted like little magnifying glasses, and burned the tissue. If it wasn’t acclimated as others stated, the tissue would be extra sensitive to high intensity light.
I worked at a nursery a while ago and when I was watering our Laceleaf Japanese Maples I had to make sure I didn’t get any water on the foliage because they were particularly prone to that issue.
One thing you can do to add thermal protection and sun protection is to use spray adhesive to adhere 1” industrial bubble wrap to the inside between the ribs… bubbles toward the poly surface. This adds an extra surface through which the sun passes and a layer of air to insulate. I do this in my greenhouses .. especially the old glass one. But unless you’re in the south you’re going to have to add supplemental heat if you want to keep things warm enough for tropical plants. Many cactus and some succulents can stand near freezing temps if they are kept DRY. And many high altitude plants.. some orchids, ferns.. can stand near freezing and moist, but they are pretty specific and not easy to mix in with regular plants that people tend to collect. The damage to your palm also looks a little like water damage. If you’re geeenhouse is really air tight and humid, the water will accumulate on the roof and when the temps drop it can condense and drip down onto the plants below, causing some water damage. It’s hard to tell though and the spots are so even that I’m not sure what’s going on. But it doesn’t really look like sun damage to me.