Sure you can. You just need to start the seeds when it is warm out. Sept. here.

Well, when you plant is going to depending on where you will be in Florida, and it will depend on what you're growing. But yes, you should be able to direct sow all of those vegetables, I think.

Short-season crops like lettuce and radishes can be succession sown pretty much all fall, winter, and early spring.

But for plants that take 50-60 days or more from transplant (broccoli, cauliflower, brussels sprouts, etc.) September sowing is a good idea. Or even August sowing (indoors) for transplant in September/October.

One thing to keep in mind is that the days to maturity on seed packets are based on spring planting dates. Here in North Florida - most plants grow very slowly from late November through January due to the short days and colder temperatures. So I have found that vegetables planted in the fall and winter usually require far more time than the "days to maturity" stated on the packet. In North Florida a killing freeze is possible, especially for tender young seedlings. Cold, wet soil can reduce germination of winter plantings as well.

One strategy to deal with slow winter growth is to time your plantings so that the plants will be at or near their harvest size by December 1. They will mature slowly and hold in the garden for a long time so you can harvest at leisure. The plants' growth will accelerate dramatically in late February.

Can and should. IME direct-seeded plants are notably more vigorous in most cases.

Biggest problem I've had w/ direct sowing cabbage & spinach family plants is that snails & slugs, & other little beasts LOVE the sprouts & often chow them out of existence as soon as they emerge. I find that most survive when transplanted @ 3-4 inches high.

Lettuce sprouts have disappeared on me as well, but most usually survive.

1 thing I've learned to do is sprinkle iron phosphate slug & snail bait around every few weeks until plants are large enough to withstand the critters.

FWIW, HTH

Well where I would plan to be to direct sow these things is in northern Florida, either Tallahassee, Gainseville or Jacksonville.

When does the season for growing hot weather stuff typically begin in Northern FL for Tallahassee, Gainseville, and Jacksonville? Essentially what month is the 'cut-off' date for growing cold-weather vegetables in northern FL with the above places listed?

I can't do anything about the shorter days, but I'd like to implement the use of a greenhouse for cold weather veggies in the colder months. Would the warmer weather cause the veggies to grow faster and increase germination rates?

They'd pretty much be grown in there until the the time frame you suggested, about Late-Feb.

I live near Jax. This is the third warm Nov. and Dec. Plants grow faster and they bolt, i.e. go to seed. The cool weather crops start dying when it gets in the 80's. We had collards all year a few years ago. Much sweeter when it is cold. The warm weather veggies start to poop out when it gets into the 90's, say June-July. By then you may not want to be outside. Okra takes the summer heat and so did some Lady Belle peppers. They never stopped until the frost. Sweet potatoes do well too.

Yes, you can use a greenhouse or hoop/tunnel cover to boost the growth of cool weather veggies. However, you're going to have to figure out a way to vent it - preferably automatically - and monitor the temperatures closely because sometimes it will get TOO hot in there. In a tightly-sealed enclosure, temperatures could climb to 100+ degrees on a mild, sunny day.

Last frost dates (a.k.a. beginning of the warm weather growing season) range from early to late March for the cities you listed. The last frost dates are earlier farther east and closer to the coast. (I attached a link to a frost date map.)

I want to reiterate what Zackey said about summer being a difficult time to grow many vegetables that you probably think of as summer vegetables. Most summer vegetables in the rest of the country are spring vegetables here - you don't want to delay planting them to wait for your cool-weather veggies to finish. They need to go in as soon as possible after the last frost.

However, peppers (especially hot peppers), eggplants, okra, cowpeas, yard long beans, and sweet potatoes like the heat and will produce well in summer. If you can plan your garden accordingly, you can keep some of the cool weather crops going on a little later if you plan to follow them with these crops.

Collards are one of the few cool-weather crops that can survive all summer, but flavor is best in the cool months. Daikon radishes seem to have some heat-tolerance, too. I am going to test some this year. But most cool-weather crops will bolt or die in April or May.

I'd love to hear how your greenhouse works out. I have been thinking I need to build some low tunnels or something for my winter veggies. If nothing else, they would provide protection when we have damaging hard freezes like the ones earlier this month.

Here is a link that might be useful: Florida last frost date map

I've lived in Tallahassee, Gainesville, and Jacksonville. You can certainly start all your "summer" veggies in April, if not a little sooner, depending on the year. Just be ready to cover your plants if the night temps dip below ideal to avoid stunting your plants (roughly 50 for tomatoes, 55 for peppers, 60 for eggplant). And even though these crops will eventually give into the insane panhandle heat, the nice part is you can also grow all those "summer" crops in fall.