Cactusfilter: How do I bring 200+ cactuses back to full health and keep them alive for the winter?

September 21, 2008 1:05 PM

I've inherited a greenhouse and it is full of cactuses and succulents. I would very much like to keep them alive and healthy but I do not know where to begin! How can I become a cactus caretaker?

I am in Victoria, BC, a temperate climate entering a rainy winter in the next couple of months. The previous owner died of a heart attack in June, and the cactuses have seen no care since then. Many of them are wilted, look unhealthy, and the greenhouse is dirty and falling apart. There's some fans and a lamp inside.

I would guess there's about 200 cactuses in the greenhouse.

Some of them are labelled echinocereus, opunita rufida, echniocereus sheerii, euphorbia mammillaris, grassula falcata, lobivia tiegriliana, ... and I could go in but there are 200 of them. Some are quite beautiful, some hideous. Do I leave them in the greenhouse or bring them inside for the winter? If I leave them inside, do I seal the greenhouse? When I inherited it the door was wide open and the ceiling panels are lifted to allow airflow. Such questions prove my inadequacy at dealing with this sort of thing, but I would hate for the cactuses to slowly dry/die out when I feel I have come across such a marvelous collection.

posted by ageispolis to home & garden (4 comments total)

Keep them on a cool dry windowsill over the winter. Minimal water. They wont tolerate frost very well, most of them, so don't close the curtains on them.

Over winter, they'll go pretty dormant. If the pots are bone dry at any point, give them a little trickle of water (the same goes for if they start to shrivel), but don't overwater them, as this will kill them faster than anything. Also, don't feed them until spring.

It might be worth giving them a drink now, so they can plump up before winter. Put the pot in a saucer of water. Anything left after 30 mins, throw away.

If it's warm where you are, you might extend the growing season a bit. The main concern is light, and keeping them on the dry side. They're designed to handle dryer conditions better than wet, obviously. :)
posted by Solomon at 1:12 PM on September 21, 2008

There's almost always a nearby enthusiasts club for specialty plants. In my experience, such clubs are comprised of members who are very into (as in talk your ear off for hours) their planty interests and welcome newcomers with questions. The advantage is you'll get care instructions that will fit your local climate.

A quick googling did not turn up one in Victoria, but contacting these two clubs might give you a lead on members who closer by:

Desert Plant Society of Vancouver
Burnaby Cactus & Succulent Club

Regarding the greenhouse: does it have a source of heat? If it's a warm or hot frame (meaning it has a heat source in addition to the sun), your plants will be fine outside during the winter. If it doesn't, you'll probably have to bring them in. Personally, I've found it a lot easier to rig up* a heating system for a greenhouse than find room with ample winter lighting indoors for 200+ plants. Charley's Greenhouse & Garden is my favorite source.

The vents were open to let out heat and prevent an overabundance of humidity from building up. You can close those now but remember to pop them back open if you hit a late-summer/fall heat spike.

*If it's a small-ish greenhouse, several strings of Christmas bulbs will do.
posted by jamaro at 1:33 PM on September 21, 2008 [2 favorites has favorites]

Overwatering cactuses is the most common way for beginners to kill them. Remember that in the wild cactuses are used to seeing two or three rain storms per year and that they don't grow in places where it rains a lot more often than that.

The second most common way is to not let them get enough sunlight. Remember that in the wild their normal habitat is sunny and dry.

That goes for succulents, too. If their leaves are fat and stiff, they don't need water. If the leaves seem shriveled and a bit limp, water them once. 99% of the time the soil in the pot should be bone-dry, because that's how it is in the wild.
posted by Class Goat at 1:52 PM on September 21, 2008 [1 favorite has favorites]

There are a lot of good "Here's some general cactus care & feeding" books, most with a healthy dose of "Oh, and by the way, this is what the hell that plant is." Most decent ones are about equally decent, IMO, but an inexpensive and "We know you're not stupid, but here's some basic stuff" one I have is this one, published by Barrons. It's worth getting some reference materials, and do hook up with your local enthusiasts' group(s). I'm very jealous, by the way. Best of luck.
posted by Emperor SnooKloze at 2:20 PM on September 21, 2008