the protected cold frame

Jane McGary
Tue, 20 Jan 2009 10:28:32 PST
Jim McKenney's description of his "protected cold frame" is a little 
different from what I do -- he covers it with a tarp outside the 
lights (the plastic or glass), but I put sheets of microfoam 
insulation directly on the plants before shutting down the lights. 
However, both strategies seem to have brought our marginally hardy 
bulbs through recent below-average temperatures. My low here was only 
14 F (minus 10 C), but the temperature did not rise above the 
freezing point for about ten days. I pulled the foam off as soon as 
the day temperature began to rise, although this entailed working in 
snow over knee height. Only a few plants seem to have lost their 
foliage, and I think they may survive, though set back. Narcissus 
cantabricus and romieuxii varieties are continuing to flower well 
despite having been buried in bud or even opening their flowers, and 
deprived of much light for 2 weeks because of the foam and the snow 
on the lights. (I think some light gets through the microfoam sheets, 
which are white and very thin.)

Jane McGary
Northwestern Oregon, USA

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