Even though the temperature are in the 20's outside, on a sunny day the greenhouse will easily reach the mid to high 60's or more by afternoon. As winter progresses, I find I spend more and more time piddling with things out there, whether there's stuff that really needs to be done or not. To tell the truth, I have automated as much of the greenhouse systems as I can ... so it's not like I have to be out there every day.
Misting the cuttings? I have a Mist-a-Matic timer. My water line is heat-taped and insulated, and it's been fine for two winters so far.
Heat? I use an 18,000 BTU ventless propane heater on a thermostat. This big propane tank lasts about 3 weeks, and the price of propane is a little bit lower than it was last year.
I have to keep a small crack in the door open to supply a bit of fresh air, because this heater has a sensor that will shut it off if the oxygen drops below a certain level.
Ventilation? I have automatic electronic vent shutters and an exhaust fan ... not that things get warm enough in winter for them to come on, you understand.
My most pressing winter concern is aphids. The cool, damp, sunny conditions in the greenhouse are perfect fuel for an explosion of aphids if I'm not vigilant. Lately, with everything surrounding my father-in-law's illness, I have been a bit neglectful and the aphids have begun to get the upper hand.
I don't use insecticides of any type in my garden ... I don't need to. There are plenty of predators that keep the bad bugs in check, as long as I don't do anything to mess with the balance of power. The greenhouse, however, is a different situation entirely. I cannot allow pests like aphids or spidermites to suck the life out of my cuttings, potentially destroying next year's crop. I have to rely on judicious use of chemicals.
Insecticidal soaps are great for aphids ... but they're not labeled for use on cuttings. Systemic insecticides are more efficient against sucking insects anyway. Orthene is good ... just not so good for humans, so I don't use it. After considering all the various options, I settled on Merit (imidacloprid). It's labeled for greenhouse use and for use on roses, it doesn't harm my cuttings, and it does a good job wiping out aphids. I apply it with a spray bottle to minimize extraneous airborne particles, outfitting myself with mask, gloves, goggles, etc.
I sprayed on Thursday afternoon. Today, I'll go out and wash things down. Aphids secrete honeydew, which is sticky and can foster growth of mold, so I have quite a bit of cleaning to do. While I'm at it, I'll cull any dead cuttings (not too many, thank goodness), rearrange the rooted babies, and organize my tools and supplies ... if I get that far.
