Im keeping some more tender plants in a barely heated (low energy heating cable) Mini plastic greenhouse. Does anyone know if it is necessary to vent air during the winter and how often this should be done?
I would look to see if moisture is condensing inside the structure, particularly if the plants are wet all the time. Such a condition will cause problem with rot and disease, and requires some change of air. With heat in there, as long as the structure is like all that I've ever seen...quite "leaky"...humidity is manageable...since the moisture is driven out somewhat by the higher temps inside cp. outside. Much like older vintage houses which are always very dry inside in winter. Newer energy efficient houses are air tight and actually have humidity problems along with mold growth in winter...so that's why I mention the "leaky" nature of greenhouses. If your's is airtight, you will need to do some airing out at times. Also be as sparing as possible with watering...sounds like your plants will be kept just alive overwinter, so won't need regular water to grow. I keep most things in my greenhouse barely moist overwinter...rot kills more things in our area than cold, most winters.
Sudbury I was thinking of a small greenhouse for overwintering dormant figs. How big is your mini greenhouse and how much energy cost per year (approx) to maintain the set (?) temperature in the greenhouse in Sudbury. Is it outside in the snow in the winter?
My green house is about 3ft x 3ft x 3 ft. This is my first year using it so I'm not sure of what the energy cost will be. The heating cable gives off heat just above body temperature so I hope that it will be able to keep the small space just above zero throughout the winter(although I'm counting on the sun to help a bit too) because I want the plants to stay dormant too. The greenhouse will be outside in a sheltered spot beside the house in the snow. I have a slanted roof on it to shed the heavy wet snow of early and late winter. I just build it out of 2 by 2s and a few layers of greenhouse (vapor barrier ) plastic. Hope that helps.
Sudbury Thanks for your response. This was my first year growing figs. I mail ordered two plants last April from Grimo Nut Nursery in Ontario (Niagra area) and planted it in 5 gal plastic pots in normal garden soil with some compost, made sure the soil stayed moist and the fig trees did the rest. Fig trees do not need too much fuss in growing in a sunny spot. However two issues need attention/solutions in Zone 5 and 6. The first is winter protection and the second is how to get the figs ripened. My figs are going into dormancy now and in a week time I will be taking these to a cold dark space in the basement for overwintering (which does not make everyone happy here so the greenhouse question). Each of my two plants produced 7~8 fat fruits but only one had a chance to ripen in the first week of October and the rest just stayed raw green, now composted (but it was fun to watch them grow). I have been told that as the tree matures the ripening process gets faster. I hope it is so. I think you should try figs. The other source is "Adrianos f Fig Trees" in oakville near Toronto. BTW I am asking everyone if they know of a mail order nursery that ship to Ontario and has "Ranier Cherry" and "Redhaven Peach".
Figs would be another fun thing to experiment with. Ive already grown a few banana plants that Im overwintering in the basement too and the green house is for my hardy palms. As for your figs try http://www.broadwaygardens.com/products/hardytropicals.html I ordered my stuff from there with good results. Im not sure if they have figs right now but they would know where to order from in Ontario of you ask them since they are situated in Niagra.
