overwintering seedlings

[scousetigger]

Could anyone advise about overwintering 8-9 month old seedlings....I have a 6'x6' unheated greenhouse. I do have a small fan heater with a frost setting on but would only use this if we have prolonged frost. In one of the books I have it says you can keep them indoors in the light but where there is warmth especially overnight. Or could I keep them in the greenhouse and cover them at night with fleece and bubble wrap? At the moment they are in a thick brown cardboard box with a polystyrene packing sheet in the bottom as it is sometimes chilly at night now. Also will the drop in temp. sometimes down to around 5 on odd nights, stop the cacti that still have lots of buds on, from flowering?

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[scousetigger]

a close up of my three headed monster lol. Taken this morning.

EAaI (77.63 KiB) Viewed 6193 times

[Phil_SK]

I'd overwinter them inside. Cacti that can cope with low winter temperatures need to be ultra dry to do so. Seedlings that size will probably suffer from such a long drought. You don't say what plants you're thinking of overwintering in your cold greenhouse or what seedlings you're growing - there is quite a range of minimum temps that suit different plants.

I'm surprised you have lots of cacti with flower buds on at this time of year as a vast majority flower in spring (some Mammilarias, Turbinicarpus, Ariocarpus being exceptions that spring to mind). I might sacrifice these flowers in order to get them dry enough to survive winter chillyness. Many cacti flower better the following year if they've had a proper cool, dry spell. If some of your plants didn't get this last winter (but were kept growing through winter) they might be confused about what time of year it is. This often happens with houseplant cacti.



Post Edited (10-07-06 07:58)

[scousetigger]

As these were from a packet of mixed seeds I don't know what they are yet. The three headed one and the biggest one look like they culd be Gymnocalyciums but I don't know. All the other cacti and succulents will have to overwinter in the greenhouse but I have got a small fan heater with a frost setting on which should help. I also thought of draping some bubble wrap over all the plants at night and removing it during the day....would this help?

[Phil_SK]

I'd err on the side of caution, especially as seedlings take up so little windowsill space. For the other plants you'll save money on electricity costs if you can bubblewrap the greenhouse rather than the plants, but yes, in principle, covering them overnight can help (I've used newspaper on odd occasions in the past.
PS: I've added to my last post, if you want to reread it.

[scousetigger]

This is my first year growing cacti. I only started in about May. I have quite a few in bud including my big Astrophytum ornatum which has about 4 large buds on it and has only just closed up the three that have been open for a while now.

[scousetigger]

new buds

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[scousetigger]

This was a rescue plant that already had buds on but they did nothing but the one marked with an arrow is a new one. Also what is this cacti? I have had a look in a couple of books I have and think it may be a parodia uebelmanniana....

4RyWRXhpZgAASUkqAAgAAAALAA8BAgAJAAAAkgAAABABAgAPAAAAmwAAABIBAwABAAAAAQAAABoBBQABAAAAqgAAABsBBQABAAAAsgAAACgBAwABAAAAAgAAADEBAgAUAAAAugAAADIBAgAUAAAAzgAAABMCAwABAAAAAgAAAJiCAgAFAAAA4gAAAGmHBAABAAAA6AAAAAgDAABGVUpJRklMTQBGaW5lUGl (93.68 KiB) Viewed 6192 times

Post Edited (10-07-06 08:46)

[scousetigger]

This one I had to repot a few days ago as all the young ones round the base were pushing the sides, on the pot they were in, out of shape. I thought it would do better in a shallow bowl. This also has a bud.

4RylRXhpZgAASUkqAAgAAAALAA8BAgAJAAAAkgAAABABAgAPAAAAmwAAABIBAwABAAAAAQAAABoBBQABAAAAqgAAABsBBQABAAAAsgAAACgBAwABAAAAAgAAADEBAgAUAAAAugAAADIBAgAUAAAAzgAAABMCAwABAAAAAgAAAJiCAgAFAAAA4gAAAGmHBAABAAAA6AAAAAgDAABGVUpJRklMTQBGaW5lUGl (88.29 KiB) Viewed 6192 times

[Jez]

Hi Scousetiger,

This one looks like the Noto. ottonis that I posted a pic of a while ago, though perhaps a bit greener (posted under Notocactus x to identify). I think uebellmanniana has purple flowers, whereas ottonis is yellow (or pinky orange if it is var venclusianus.... asI found out from the very helpful replies I got).

Jez