I created a cylinder that’s about 3’ wide (diameter) and about 5’ high with concrete remesh, I then wrapped it with R-13 insulation covered with bubble wrap insulation (I glued the R-13 to the bubble wrap before wrapping around the remesh), then used aluminum tape (the same type used with bubble wrap insulation around air ducts) to fasten the insulation material around the remesh. The top of the cylinder is similarly covered with the same insulation. Before covering the figs, I prune them and tie smaller branches to fit inside. I also put a bowl of moth balls under the cover to keep voles and mice away.
This design (which I learned from @jrd51 ) allowed my figs to withstand sub zero temperatures with minimal damage (I believe down to -8F).
Speaking for myself – I never vented. That seemed just a way to let warm air out / cold air in. And in ~10 years I never had mold damage except minor damage where there was prior damage to the tree (e.g., a messy pruning cut). IMO, mold is an opportunistic agent infecting dead organic tissue (killed in some other way, e.g., cold). I’ve removed covers in spring to find trees dripping wet from condensation with zero mold.
I have a friend who also lives in RI and also uses an insulated cover. He measures temp and humidity inside. With no venting, he has near 100% humidity, as expected. He has experienced no material mold damage.
I was just surveying my fruit set for the year since most things have finished blooming… That one freeze did even more damage than I had thought. My asian pears are basically non-existent, I had a huge bloom and now there is only a fruitlet here and there. The Euros are quite a bit better but still about half what I was expecting. For some reason the plums didn’t get too bothered, most of them have a full set. The apples also didn’t do so well, I had a great bloom and some things set well but many either set much less than normal or almost nothing. Apples usually don’t get bothered by frost at all, this is the first time I can remember.
With many fewer fruitlets the curc is also a bigger problem, more fruits are taking damage than usual since I have the same number of curcs but fewer fruits for them to prey on. I skipped spraying the apples until now due to high wind, but I wished I hadn’t because last night was a little too warm and I had quite a bit of damage just from that one night. The plums are relatively better because I sprayed them before the high wind hit.
It was a very unusual event, my guess is the length of time below freezing was much longer than any of the past events. Maybe there were some other factors as well such as wind etc.
Anyway, always look on the bright side, fewer trees to keep spraying from now on, and a lot less thinning to do
I also did a more extensive evaluation. Apples did so so. Asian pears are really thin. Euros set nice, but all something on the fruitlets. Plums set nice. Peaches nice. Apricots total loss. Cherry pretty thin. Almond total loss. And to finish the package a bunch of my potted plants died.
Sounds like you did worse than I did. I didn’t mention the cherries but mine have a nearly full set. The peaches did pretty well for me as well, maybe 3/4ths of the usual set.
