They will be ok for a few more weeks. A light frost won't hurt them. Can you cover them with row cover? Here was some broccoli I grew several years ago. Planted on a schedule similar to yours. It was all harvested on November 14th, before a snowstorm. We spend the day blanching and freezing broccoli while it snowed outside.

Mid July is probably way too late to start cabbage and broccoli in zone 4. Here in zone 6A, I start my savoy cabbages in mid June, set out in late July or early August.

Hi Jillian

Can you tell us the name of the Broccoli variety or the DTM? I agree in 4b that you probably need to start from seed in mid June and plant out in mid to late July but that also depends on the DTM of the variety. Broccoli can be all over the board with DTMs as short as 45 days and as long as 80 days I believe. With the waning sun of Autumn you need to add a week or so to the DTM as well. Here in 6a I will start my first Early Dividend Broccoli (45 DTM) on July 1 or so and then start more mid July and the last at the end of July. I plant out each batch at 4-5 weeks from seeding. I then start harvesting the first plantings around Sept 20. I am just now starting to harvest the main heads from the last planting while still getting lots of side shoots from the first.

Mature Broccoli can take temps down into the mid 20s or so. Hopefully your hard freezes will hold off for a few more weeks. No sign of any little nickel size bright green heads yet? Usually it takes about 2 weeks to go from nickel size to 5+ inch heads.

I can't comment on the cabbage as I have never grown them in the fall.

Cabbage will also stand temps into the low 20's.

I wouldn't expect anything planted in late August here to mature, unless it is extremely fast producing DTM (i.e. 30). Cole crops generally require 60-90 after transplanting. As discussed in other topics recently, just because the plants will survive sub zero temps in late Fall doesn't mean they will grow to maturity in them. I hope you have a lucky season. :)

This is my first year gardening (obviously!) so thank you all for your advice for next year. The broccoli is Dicicco, and cabbage is red express. Both had DTM of around 60-70 days if I remember correctly, but I was counting from the first appearance of sprouts indoors rather than transplant date. One broccoli looks almost ready to form a head, and a couple cabbages have leaves in the center that are starting to curl inward. I don't have row covers but am planning to do Coles in a raised bed next year so that I can use covers in the spring and fall. For the time being I will add another layer of mulch and hope for the best! Is additional fertilizer a wasted effort at this point? They don't appear yellow or stunted, just growing slow due to the time of year.

Raised beds are not necessary for covering -- if you're interested in saving what you've got this year, Johnny's sells really nice quick hoops that you stick in the ground, tie string from one to another, and cover with some fleece and you've got a great cover in about 10 minutes (and not too much money). I cover the edges of the fleece with rocks and fire wood logs to hold it down.

If you've got the beginnings of heads of both crops, it sounds like you're heading for some success over the next several weeks, especially if you can cover. Don't forget, the leaves of both plants are good to eat, so do use those if you've got hard frost threatening.

Good luck! Let us know what happens. It will be a good reference point.