GH and Cold chamber

[charlpic]

I've been thinking a lot about the way I could get the best dormancy conditions for my plants next winter.

So I decided to build something that could act as a cold chamber in the house but that could also act like a greenhouse during the summer. The project is starting and I don't have a schedule.

I made some plans using Google Sketch Up.







Plans will probably look nicer than the real one but as long I it helps me deal with winter, i'm good. The pictures lack of some components. I just made these to get things clearer in my head. This is not very big L18" x W36" x H34" as it has to fit on my windowsill in winter and be on a tiny balcony in the summer. It will be made of 2"x2" pine wood, polythene and clear polystyrene.

[iann]

How's it going to stay cold? Will you open the window a little so the chamber is almost like being outside?

[charlpic]

Yes that's my plan. I live in a kinda old apartment (1900) and windows are very badly insulated. Since this mini-GH has to fit on my balcony, it's size will make it almost impossible to heat if I leave it outside with January low average of -18°C... and I'm not even talking about cost.

I will instead bond the mini-GH to the window with polythene. I will also monitor temperature with an USB thermometer, use a computer fan to draw cool air from the window if I need it and open the little door if I need heat inside.

That is my first try at this but I think this setup gives me best of both world or summer & winter without being too costly.

[daiv]

Not too bad of an idea. Certainly making the most of your situation. Definitely post pics as you go!

[charlpic]

Told you I didn't have a schedule... The thing still isn't finished but it only misses another front door and the side door. I'll now be able to let my plants outside until the end of the summer without compulsively check the weather forecasts.

I hope they'll get enough light in it. It can't be as bad as inside.

More pictures when it's completely done and ready for the winter.

[daiv]

Cool to see it go from drawing to real life!

I agree - they should get a lot more light then just in a window.

[charlpic]

This is how it looks right now, on my balcony. I know it is not "that" clean but, after all, that's my first wood working project so next projects should improve.



Next summer, it will really saves me some time getting the plants in and out and hope to forget about etiolation (which I faced this summer) when a whole week of rain comes up. I have too much plants (or not enough windowsill space) to give each one of them proper light inside. Also, my cacti flowered far less than I expected this summer. In some way, I realized it was a must if I wanted to keep this hobby going.

We are around 12°C for night temps right now so I'll soon have to consider bringing them in for the winter. In the winter setup, the plants will be inside, in the box, facing a SSE window. I plan to have a small pipe communicating outside. If the pipe is not enough to cool down the box to, let's say 8-10°C, I'll keep frozen 4L of water in the box to help reduce the temp. This room is unheated in winter and gets down to 15-17°C during winter.

In anyway, I should (and must) be able to provide more light in summer and cooler temps in winter with this. Let me know what you think... even if you you think it's gonna fail.

Let me ask you what's the trigger for you guys that have an unheated GH for bringing your plants inside for the winter? I was considering <10°C night temp. Is it safe ? Too safe ?

[daiv]

that's my first wood working project so next projects should improve.

Absolutely! That's one thing Google Sketchup can't do - substitute for hands-on experience.

I really hope I can build my next bigger greenhouse next year. I can't wait to use what I've learned and learn some more in the process.

[iann]

There are species that don't appreciate being below 10C but I wouldn't imagine it would kill many cacti. Then there are plenty that couldn't care less until it starts to freeze. Depends what you are growing.

[charlpic]

From what I can read on the web, most of them can take frost for a "short period of time" but prefer a 10C min avg. When I read this, does "short period" means an hour or two? a whole night ?

Here are the dudes in the GH at the moment:

Aloe marlothii
Aloe variegata
Astrophytum myriostigma
Austrocylindropuntia subulata
Copiapoa hypogaea
Crassula ovata
Echinocactus grusonii
Echinocereus pentalophus
Echinopsis chamaecereus
Ferocactus glaucescens
Ferocactus latispinus
Gymnocalycium carminanthum
Haworthia attenuata
Mamillaria elongata
Mammillaria matudae
Melocactus sp
Opuntia compressa
Opuntia polyacantha
Oreocereus celsianus
Parodia haselbergii
Parodia leninghausii
Parodia scopa
Parodia warasii
Pereskia aculeata
Rebutia archibuiningiana
Rebutia arenacea
Stetsonia coryne

I would think the Melo and succulents might be the firsts to knock on the door to get in. With them in, I would wait for 3-4 consecutive nights around 6-7C to bring them all in. Thing is that it will be hard for me to provide constant ~10C temp inside before it gets much colder outside. Hope they won't be fooled into growing again.

[iann]

but prefer a 10C min avg

I still don't know what that means. Everybody copies it from everybody else but never have I seen an explanation of what it actually means.

[charlpic]

Hehe I was kinda hoping someone could clarify this (same for the term "can take frost for short period of time"). I would understand it (min avg temp) as: an average cold day would be 12High/4Low or something like this.

Now that I'm writing this, I'm feeling kinda stupid. I should probably check out normal/usual temps for the regions those plants come from. And not worry too much.

I'll aim 5~10C and try to avoid frost.