I have about 50 brocs and 30 cabbys in the garden and temps are suppose to drop below 28 tonight. Must I cover? If not, how cold must it get before these green (and purple) beauties are damaged?
They'll be fine. Mid-20s is OK for a first time frost, but for later frosts, they can tolerate even low 20s and upper teens. Cabbages are overwintered in Europe.
My savoy cabbages have taken below 10 with nary a sign of damage.
At what temp do they stop getting eaten by pests?
"At what temp do they stop getting eaten by pests?"
I would guess that insects mostly give up about the time that it begins to frost.
The damage to most hardy crops from cold temperatures is the result of rapid fluctuation in temperature. Whenever the cells are subjected to freeze/thaw cycles, they are damaged to a certain extent. Fast freezing traps moisture in the cells, water expands when it freezes, cell walls are ruptured. Fast thawing releases excess water into the plant, creating soft and vulnerable tissue, so they are more susceptible to biological and physical damage. This is why row covers, low tunnels, and other protective strategies are a good idea even for frost-tolerant crops.
Mine made it to 7 degrees last week when they finally succumbed.
I'm still harvesting savoy cabbage, collards, Spigariello Liscia, and several varieties of kale. Late-planted broccoli and Romanesco cauliflower plants are still green but show no signs of producing heads.
After a thaw this week, I pulled the last of this season's turnips, beets, parsley root, rutabaga, carrots, and potatoes; all but the potatoes were still showing some healthy green foliage. Berggarten Sage leaves are still healthy and green. Biggest surprise is still-healthy cilantro. We've had temps in mid-teens a couple of nights.
Is the *clap clap* you smacking your hands together to warm them up? Or trying to wake up gardeners who might have gone to sleep for the winter? Or applauding the plants for surviving freezing weather?
lols ny garden! I wondered about the clap clap myself!
I'm with everyone else - your low tonight won't kill them. I've had lettuce survive that low, with snow on them yet!