What sort of edibles?

If you're talking veggies:

http://www.johnnyseeds.com/  has good prices and selection imo

I wouldn't bother sowing at this point until about Late September and make sure with some sorts that the soil is cool enough by then, most veggies grow better during FL cool season anyway.

Tips:

Afternoon shade is your friend for vast majority of vegetables in FL if growing during warm season. We are the same latitude as Egypt, "full sun" means 6 hours of light at least (doesn't have to be all day) and our sun is so powerful many plants may not want more than 6-8 hours, especially if it's afternoon sun. If your yard has few trees I suggest getting some and planting your beds strategically to utilize the afternoon shaded areas. Otherwise, plants and the soil they are in can get too hot. Commercial growers sometimes bypass this because they constantly are watering plants even in afternoon but who wants to spend that money/waste all that water?

White/light colored concrete or ceramic pots (this is how I grow parsley all year, even in afternoon sun) are also your friend for the same reason, black plastic pots are poorly insulated and the dark color gets too hot for heat-sensitive veggies. You can use black plastic pots but make sure to either put them out of afternoon sun or place them inside a larger white pot.

[and I have a list of fast-growing native trees if you're interested]

Stuff I've grown from seed with success (CS= cool season, AM= AM sun only)

• Okra (soak in water until seeds germinate before sowing)
• Carrots (CS)
• Beets (CS)
• Radishes (CS)
• Parsley (AM or in white ceramic pot, otherwise dies in July)
• Dill (AM or in white ceramic pot, otherwise dies in July)
• Bronze Fennel (more tolerant of heat than previous 2)
• Basil, very easy and there's a lot of different tasting-varieties so it's my favorite, good for bees too (AM, otherwise dies in July usually)
• Lettuce (CS)
• Spinach (CS)
• Tomatoes
• Peppers, various
• Cucumber
• Squash
• Mint (GROW IN POT, very invasive)
• Coneflower (seeds can be expensive, honestly I just buy a plant and then clip off some of the seedheads and store in a fridge and then sow straight into ground before a week of rain or something. not true from seed so whatever you buy will probably revert to purple wild type)
• Nasturtium

Oh and you may already know this but a lot of fruiting trees/shrubs just aren't worth growing from seed, depends on the kind of course but there's a lot of people online trying to get away with selling things like citrus seeds even though they don't come true from seed. If you're willing to consider things that aren't seeds I can give you my list of recommended edible shrubs&trees.

Hope that helps and good luck