I am not a big broccoli grower as I don't eat much and I find it unreliable. Often it flowers before I think the heads are worth harvesting.

Packman isn't a variety I would grow because I have grown it and it has never done well for me.

I don't have any recommended varieties, but I would not, personally, bother with Packman again.

The key is weather and we can't control it. Spring planting should be done indoors and transplants set out. Indoor seed sowing should be done early in case the heat of summer comes early. Fall (late summer) plantings will likely do better on a consistent basis (as they generally do for cool season plants). They key with fall (late summer) plantings is ample time. Growth rate slows as day length shortens, nights cool etc. For most plants early to mid august is good timing. This way they are mature and harvestable once the first frosts arrive. For those plants that sweeten up with frosts they can be left in the garden, but don't expect them to grow any further once frosts arrive. Sweeten up, yes. Grow in size or maturity? No.

Wisconsin is challenging for cool season plants, no doubt about it. Some springs are ideal, others brutal. Some falls frost comes on time, others late, others a month or more early. This greatly complicates the timing of sowing seed or digging in plants. The more time plants can be grown indoors under ample lighting the better.

Just the way it is I am afraid :)