Last winter I put all my cactus inside with a lamp but something, a fungus maybe, showed up. Where I live (Tuscany) weather isn't extreme, not very cold winter but temperature could sometimes go under 0 ⁰C and it rains a lot. I thought I could leave everything outside but I'm worried about rotting, something black appeared on the monster, the others plants look quite healthy though. What should I do?
by giacoboh88
1 Comment
I live in a similar climate but on the other side of the globe. My winter/rainy season max lows are 0° to -2°C but typical nightly lows are closer to 4 to 5°c. It rains a lot in the winter here too.
Understand dormancy – daily highs of 15°C is your magic number. If daily highs are above this number for more than a day or two in a row, your cactus will grow, though very slowly when you’re right near the cutoff. When it grows it needs some water. If it’s barely growing the water can be significantly less than during faster growth. You can let it shrivel/dehydrate a bit before watering which is fine especially during this type of weather. They also will need light if they’re growing or you’ll get etoliation and that wavy look to the columns.
However when nightly lows get below about 4°C I want my soil to be dry to be safe. If the soil is damp when it gets too close to 0°, you’ll get rot or root rot.
How I personally handle this is leaving my plants outdoors but under a cover. I use thick clear plastic sheeting. I’ve played around with tying up plastic sheets, building a PVC frame. Ended up settling on a solidly built metal greenhouse frame. I don’t enclose it, just use it as a roof. It has a nice double use of working as a frame for shadecloth in the summer when temps get over 38°C. If you want to build something more solid, polycarb panels work great too but they’re expensive here.