Fall cole crops have insect problems in the fall...but not in the spring....here.

I transplant out broccoli and cauliflower about the 20th of July and some late broccoli and cabbage in the beginning of August.

I have not solved the challenge in zone 5/6 Ohio. It is possible to get Broccoli, Cauliflower, and Cabbage.

Heat and bugs really bother the small plants in August. It becomes easier in September with the cooler nights, and then the bugs are mostly just a nuisance in that you don't want to eat bugs. Grow well in September. In Autumn it becomes a race to grow them to maturity in October. Each year is different. Plants can survive into November but they don't grow much more in the cool weather and short days.

I've tried planting in early August, but the plants usually look horrible by the end of the month. I've tried planting around Labor Day and they grow fine but you can run out of time.

July 1 I will start savoy cabbage in pots for winter harvest, setting them in the garden in mid August. July 18 I will sow beets, carrots, kale and collards directly into the garden, covering the kale/collard sowing immediately with row covers. Other fall crops--Asian radishes, escaroles, turnips, fall lettuces, will be sowed directly in the garden in August. This works in zone 6A.

noki33, The key to fall cole crops is LOTS of watering in July and August...seriously.

Here in Z-7 central Va my very short window for Cabbage & Broc transplanting is 1 week, Aug 20-27, before that it's too hot, after that the days are too short for good size production. After experimenting for many years this is the best planting window here. Yes, the "worms" are just as bad as in the spring.

I agree with farmerdill that cabbage worm pressure is much higher in the summer and fall compared to spring. This spring I didn't see a single cabbage butterfly until half of my main head broccoli had already been harvested and I never bothered to spray any BTK.

DTM of the selected varieties has not been mentioned yet and makes a big difference. This fall I'm growing Brunswick cabbage listed as 90 days. I already have the seedlings growing and will plant out in mid July and expect to harvest around Nov. 1. Broccoli (Early Dividend -48 days, and Emerald Crown 59 days) will be started around July 7 and put out in mid August. Snow Crown cauliflower (50 days) will be started and transplanted at the same time as the broccoli. Cheddar cauliflower (68 days) will be started this weekend and transplanted out the first weekend of August. I'll use shade cloth for a week or 2 over the transplants as well as tulle to keep the cabbage butterflies at bay.

Re the cabbage "worm" and the butterfly. Row covers are the answer.