Well, I thought a lot about potting, that's what I have most of my Dwarf variants for.
But here's my new theory (to be tested this winter and next spring). According to my experience (and that of others as well), Dwarf cultivars (or any growing to 2.3m) can be stored in pots and fruit large bunches in 100 L pots. The problem there is is with the pots themselves, because potted plants grow much slower than those in the soil.
A combination of potting and free land growing might be necessary.
So here's the theory.
Based on what I have read in Frank's post about overwintering
in zone 7a, I'm positive that I could extend the period for their growth by another month in my climate (from late March/early April to early November or so), giving them temperatures of maybe 16 degrees.
And I have a smaller greenhouse, that is effective in the spring.
My intention is to do it like this:
Winter/Spring: The spring comes here a little later than it does in say Mediterranean region, but this can be efficiently compensated by that greenhouse I mentioned before. Not only, that it can effectively extend the growth period, but also could possibly eliminate the danger of sudden late frosts that tend to destroy lots of the harvest sometimes. Plants would be potted and thus could start growing.
Than in late April or early May the plants would (in full growth) go into the garden and soil (special large pots might be necessary, I even cosider creating special wooden boxes or making special extra large ceramic pots, because the plant that has grown freely once will never want to go to small pot again. Other alternative is to use polyplastic root materials, that will be wrapped all over the roots, hold the soil, bet let the water in and out - just like those you can see, when you buy young trees).
Sumer and Autumn: The first problem comes with last October or early November days, as the first freeze could occur anytime. Therefore I will move the plants to the greenhouse and there, under controlled conditions I will lower the temperatures to make them dormant. Dormant plants will be stored in the garage.
The key factor is, that the plant's adult height mustn't be more than 3,5 to 4 meters. It would become really difficult to work with. So Saba is out of the question for that matter (although I might try my theory with larger pieces too).
I also carefully choose the cultivars, they must be in the level of superb cold hardiness and have height to certain levels. So far, according to papers, this could be done with about 30 to 40 different cultivars.
I will try something out and by the time of winter, the plan will be complete.
I will also share my progress with you.
The only problem that I haven't quite figured out is, what if the plant starts blooming too late? The whole extraction and overwintering procedure will get delicate and must be done precisely.