Saturday 9 December 2017

fending off the cold

It is perishingly cold.  I set the heaters in the greenhouse and conservatory last night for the first time this winter, and have set them again this evening.  They are only small electric fan heaters, but enough to keep things ticking along above freezing overnight when the thermometer outside dips below zero.  It's forecast to hit minus two degrees Celsius by midnight, so they will be needed.  In a long cold spell, if the thermometer went well below that and stayed there, the heaters would not be enough, but it's a trade off between the heating costs and how many plants I am prepared to lose.

My big specimen plants under glass could all take a light freezing if it came to it.  The Wollemi pine, which by now is bumping up against the conservatory roof, and the standard Eriobotrya 'Coppertone' that was a birthday present from the Systems Administrator and has been repotted twice since then, would both be impossible to obtain at anywhere near the size they are now, and replacements at the largest size I could get would be expensive.  Besides which, I am sentimentally attached to them.  The ginger lily roots would survive even if their leaves were damaged, as would the evergreen Agapanthus.  I am pretty sure the dwarf pomegranates I raised from seed could take a light frost, given that you see them growing outside in sheltered walled gardens.

I take more risks with the small stuff.  No pelargoniums like to freeze, and some are more tolerant of low temperatures than others.  Generally it seems as though the scented leaf types and Uniques are tougher than some of the zonals.  I would rather not lose any of them, on the other hand I don't grow any that I couldn't replace from a specialist supplier, other than that a few were presents or bought unnamed on garden visits and I don't know what they are.  Replacements would come in at around two to six pounds each, depending on rarity, which makes them worth a few nights of the heater.

The succulents I grow are mostly Aeonium and Echeveria, none rare but some quite old and correspondingly large.  They absolutely will not tolerate freezing, which includes being allowed to touch the greenhouse glass on a freezing night.  I proved this empirically last winter trying to cram an unfortunate Aeonium 'Schwartzkopf' on to the top greenhouse shelf, so you can learn from my error and not make the same mistake.  The rosette turned to mush and fell off, and I kept the stalk hoping it would make new shoots but that died as well.

The African violets are frankly a gamble.  They all started off as rooted plugs from Dibleys, and the conservatory is theoretically much too cold for them, on the other hand I don't have anywhere suitable in the house.  The trouble with regarding them as bedding is that it takes most of the season to get the plugs to a nice flowering size.  Of course, I could not grow Streptocarpus, but I like them.  The Begonia fuchsioides is not supposed to go down below about ten degrees either, according to the nursery woman who sold it to me and who I think was quite reluctant to let me have it in case I killed it.  It spent last winter in my bathroom because I was so worried about it, but it was terribly in the way and this time round it is still in the conservatory.  I have struck three cuttings, though, which are in a heated propagator.

My potted fuchsias are a mixed bunch.  Some would be hardy if grown outdoors, at least at the root, and I only have them in pots for display purposes.  Others are rated as needing frost protection.  I have chopped them all down very low in my campaign to try and eradicate the fuchsia gall mite, before deciding whether I will have to follow the RHS advice and throw them all away, and by now the pots should be pretty dry.  Keeping doubtfully hardy plants dry in winter can help them survive the cold.  Also, when I was packing the greenhouse I put the pots of the most tender things towards the middle, and the relatively hardy things next to the glass.

After tonight I might not need the heaters for the rest of the week.

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