I've already planted spinach and collards. I have to plant them very early to beat the daylength down here. They do much better as fall/winter crops, but we still get decent yields in spring from a very early (as in, earlier than the OSU-recommended planting dates) planting. I like to harvest and use all greens when they are younger and more tender anyway, and the daylength issue just makes me ensure that I do so. I originally started growing Swiss chard and red malabar spinach as warm weather subsitutes for spinach because I wanted some greens that would tolerate both our daylength and our hot weather.

Many cool-season plants are daylength sensitive, and some are temperature sensitive and some are both. That's why we have to rush them into the ground in February when the temperatures at night still are often cold enough to damage them. For many years, I didn't bother planting many cool-season crops (other than potatoes and onions) because of this issue. The further south you are, the more of an issue it is. With anything that seems daylength-sensitive, I plant extra early and also choose varieties with shorter DTMs. With plants that are more temperature-senstive than daylength sensitive, I position them at the northwest and west end of the garden where shade from adjacent trees will shade them in the afternoons. That can keep plants like lettuce producing much longer. And, with some things like lettuce, bolting is a function not only of daylength/temperature, but of dry soil as well so if I am extra careful to never let the lettuce get too dry, I sometimes can keep it alive until July. Still, at some point it begins to bolt even when it is only in morning sun and is kept moist. I also sometimes use shade cloth over tomato and pepper plans in the hottest months of the hottest years. Keeping them cooler keeps them in production longer. It takes a lot of effort to keep some plants happy here in some years. I also grow rhubarb in morning sun, afternoon shade, and that keeps it from going dormant too early.

There's also some pole bean varieties that are daylength or temperature sensitive, and I only tend to grow those as fall beans unless I can plant them insanely early in spring, which may or may not allow them to produce spring/summer beans. Some tropical varieties of other types of crops are daylength sensitive. I haven't researched it, but I think roselle likely is daylength sensitive. It doesn't matter how early I plant roselle plants or how big and healthy the plants are, they aren't going to flower much if at all until late summer or early autumn, so there's no reason for me to hurry them into the ground. I can just wait and use them to fill in bare space after harvesting earlier crops.

Autumn is much better for cool-season crops here, but lately I find that if I'd had a huge summer garden and have had to fight heat, drought and grasshoppers, I'm just not much in the mood to deal with a big fall garden---particularly if we're having a difficult summer wildfire season. I think the last year that I had a gigantic fall garden was either 2012 or 2013, and most likely it was 2012. Every year I say to myself "this year I will have a big fall garden" and then fall rolls around, and I don't do it.