At my previous residence, I had a large four seasons solarium attached to my house. During the winter, it was maintained at just above freezing and in there I grew everying from grapes, to roses to passion vines and camellias etc. Heating was supplied by a furnace vent and a few baseboard heaters plugged in during the very coldest of winter days. The biggest troubles was dealing with spridermites, though beyond that not too much headaches. Really should have built myself a similar room at the new place, cause I sure do miss having spring in February and the fragrance of things in bloom! I am now though considering a detached greenhouse to grow blackberries and grapes.

Say I had a raspberry or grape in a greenhouse, would there be issues in the winter if the greenhouse got up to say 50 degrees every day and as cold as the temperature outdoors? - so at least teens most winter nights?

That type of temperature shift might cause them to wake up before they are ready. Is it possible if you open the doors during the day to let more cold in?

My greenhouse gets down to outside temps at night and it can be -40 here in Jan. The day time temps are still in the minus category even if it is sunny so I don't have the problem of them awakening too soon.

You would likely want a source of heat to buffer from huge swings of temperature in your greenhouse. Mind you, you could also just use the greenhouse as a season extender and totally shut it down for the winter. Though, then it would become almost every bit as cold as outside and any plants being of more tender nature would need to be laid down to the ground and given a deep layer of straw protection, I think Ubro does such a thing.

Yes I do froze bud, and actually it is quite easy. When you are dealing with seedless table grapes that produce a ton, it is totally worth it for unsprayed grapes. Black berries are another great greenhouse extension crop as they produce very well and are insanely expensive in my neck of the woods.

I used to do veg. in the greenhouse and I still stick some tomatoes, garlic and peppers in odd spots but my theory is this, if I have a greenhouse and want it to be profitable I want to grow the crops that would cost me the most to buy, and that, in my area, is fruit.

Ubro, I would like to get around to doing the same, those homegrown seedless grapes and blackberries are something else! Last year, I did have a pretty good crop of 'Balsors Hardy Black' blackberries, quite productive and delicious, though best to be laid down to the ground for the winter and being awful mean prickly things to work with, I want to instead grow thornless!! I did not protect the blackberries this winter and they've now likely succumb to the bitter cold, really should have made the effort, but now will have to wait and see!

Urbo - How do you keep your blackberries and grapes alive? Certainly those are not hardy to -40?

Clark, my grapes are big and no they are not zone 2a but the best performer is Suffolk Seedless. They have been in for 5 years, but I expect any year they could die, nothing is a guarantee in Sask.

They are planted in the ground, my greenhouse is a hoop house 16 ft wide and 20 ft. long ( I used to do commercial cut flowers). It is unheated from Oct. till the first of April so yes, it gets -40C in there. We heat it with our wood boiler which also heats the house and shop so for me, heating cost is not an issue.

I planted one grape corresponding to one hoop so I could tie the vines to the hoops and let them grow up and over the top. I will say the shade they provide to the rest of the plants in the summer is very beneficial. I don't use a grid as it is way too hard to pull all the vines out of the holes. When I want to lay them down I just clip the strings holding them up, then roll all the vines up like I would roll up a garden hose, lay it on the ground, pin it in place with ground cover staples and put wood chips, straw, pine shavings or whatever I can find over them. I found the straw and shavings to be a mess in the spring so I now put those in large bags.

If the original grape is planted in the hole at a 45 degree angle so the top is almost parallel with the ground the trunk, when it gets old and thick, will not hinder the rolling up process. In traditional planting that heavy trunk stands upright and there is no way to lay it down to cover the vines. My process is not the best system in a warmer region but is one of the easiest and least time consuming chore I have so far.

This year I was short on my straw so once the snow came I just took my big push scoop shovel and piled snow on the whole lot.

As for the blackberries I just let the new canes grow along the ground, they will produce fruit the next year, and then in the spring I take out the old ones and tie up the new.

I also think, but I am no expert, that it is not just the cold temperature that does injury but the duration it remains there. In a greenhouse it does dip to -40C or lower, but that temp. is only for a short time because when the sun rises even though the outside temp may only get to -37C inside the greenhouse it gets much warmer.

I posted these pictures somewhere on this site but here they are again incase you didn't find them.

Suffolk seedless, these are not ripe but they do get redder. Of course I am assuming they are Suffolk I have gotten mislabeled plants before. Notice the white plastic tie wrap holding up the grape clusters?

Clark, if you wish to try some other types of fruit such as pears, apples or plums, and you don't mind a little pruning and caring for plants, I suggest you goolge 'step over espalier'.

These are done within 12 to 14 inches from the ground like a low fence but are easier to cover and protect in the winter. I am trying both apples and pears this way, I know the production will be possibly lower but hey, we are only two now and what better treat than a juicy apple or pear I grew myself and would not be able to grow in my zone any other way.

Frozebud, which blackberry do you like the most? I want to replace my Chester but with so many choices, and growers all saying that the one they sell is the best I don't know where to start. Don't be too sure it is dead, the root might be fine.

Thanks for further describing your greenhouse growing and wintering techniques. Those grapes look amazing and makes me yearn for when I had greenhouse grown 'Himrod' seedless.

I only have the 'Balsors Hardy Black', honestly it was very slow to come into production, it seems to prefer cooler and more moist conditions than I would have expected, but when happy it sure is vigorous! Despite the total lack of sunshine and heat this past summer, the patch produced a decent good crop, though as previously mentioned, canes had been laid to the ground and covered over with snow. Otherwise, these are not quite hardy enough for my climate, though a good choice for places that are a soild zone 4 and for folks that don't mind the mean razor sharp thorns! I'll check on them in a few days to see how they've fared, they likely have not died all the way down, though won't produce much of anything if having lost most of their tops. My raspberries are a bit different in that they can die to the snowline and still produce a good crop with 18 inches of live cane. From what reading I've done, I would think 'Arapaho' is probably one of the best choices, is early maturing and semi trailing, thus a bit easier to lay down and protect. It's available in Canada, but I'm not finding a place that ships. 'Triple Crown' is a possible consideration and several weeks earlier ripening than 'Chester'.

I had no idea grape vines were supple enough to do that. Fascinating.

The vines, depending on diameter, make either a larger or smaller circle. I bend them into whatever size I can without cracking the vines themselves.

Thank you for the grape tips Ubro. I hope to try grapes in the future. Good to know Suffolk Seedless is a good performer for you & the 45 degree planting is a great tip.