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