Hello all. Mark here, been a while. Had a cactus party this summer and was left with more then just prickly pear cactus, as my sun room is full up with succulents i decided to make a cold frame out of some left over building material i had been hording since last fall. Here is photos, it contains pricklys, agave, mamalaria, notocactus, ferrocactus, graptoveria, ETC . I did not insulate the bottom or sides and there is a 1 1/2 inch gap all the way down the front of the window. the window swings on three hinges and rests on a board for airing out. THinking about cutting ridigid foam for fit bottom and front gap but worried i will then cook cacti on hot day. Will update later this winter or spring let know survival rates.

Great setup Mark!

I wouldn't seal it because you also don't want humidity to build up in there and rot all your furry little friends. You will need a good amount of airflow.

How cold are your coldest temps and how often do they happen?

That's a cool looking cold frame, Mark.. I don't think that you get much colder than we do here in SC. Last winter I kept almost all of my cacti and succulents on a covered stoop. I used a frost cloth at night and took it off during the day. If we had precipitation, I used an old shower curtain to cover them. And if it got below freezing for an extended period of time, I threw a blanket used for moving furniture over them. Fortunately we did not have any temps in the teens that I recall. Otherwise, I would have hauled those plants into my garage. Unless I can convince DH to build me a cold frame, I will be keeping them on the covered stoop again this year. Hoping that it's not an extremely cold winter.

You would be amazed at how much heat a candle gives off in an enclosed area.

So interested to see your results. I'm in zone 8a as well in North Texas. I want to expand my non-hardy succulents but my wife says I have too many plants next to the window. I looking at doing the same but adding a small space heater through a thermocube.

What side of your home is the cold frame located?

Hi Mark!
The cold frame looks great. Your cacti look so cozy.
I have never tried to keep cacti over the winter in my plastic cold frame here in Seattle. I do put cuttings and "iffy" plants in it though. So, a few thoughts:
Mine gets bone dry eventually, even though as you know it rains here nonstop all winter. I actually have to work to remember to occasionally water in there. If I am seeing correctly though, the gap you mention will allow rainfall in? If so it may mean yours is not so dry. This could possibly lead to more disease risk although I am just speculating.
The slugs find it a nice cozy home too...
Be a little careful- yours is very close to the wood siding on your house, this could contribute to a rot problem over time.
Please keep us updated on progress this winter!

Thanks for the feedback all. I closed up that gap with a 2x2 . too much rain was getting in during those windy rainy days we were having. no slugs yet. I have NEVER seen a slug in my yard or slug trails.... Could be becouse south park is part of the duwamish superfund and our soil is FULL of dioxions. whatever. anyway @pistil You water cactus during winter in your plastic cold frame, How often? I was wondering if i would need to water them at all this winter.

@nscottreed it is on the south side to get that sunlight.