Hi Calliope, I know what you mean, but those plants that can be planted before frost date usually can take frost easily. My nasturtiums, e.g. went through a few snow falls last year with their beautiful leaves and flowers before they finally yielded. I agree that one must know his area well and know how to estimate (though we cannot be 100% accurate). For some annuals, I wait 2 weeks after our formal frost dates, then check the forecast for the next 10 days, and if it looks good I can plant them. For tender annuals, I might wait a little longer or start indoor. For half-hardy or hardy annuals, I can start earlier.

Heavens no. It's just barely safe for most crops. I'm in the Detroit area, so we have the same climate. It MAY be getting "iffy" for some of the cool weather crops like peas or lettuce, and onions planted now won't be as big as if planted in April, but even with the cool weather crops, it just depends on the season we have. Many years, it's not all that hot and they do fine into the summer. Realistically, you can plant cool season crops from late March/early April until about the first of June, and then do a fall planting from mid July through mid August (depending upon the crop and days to maturity). With warm season crops, from mid May through mid June, with a few things as late as early July (say, a really late crop of corn). Get out there and plant! Not a problem at all.

We can plant zucchini into late August in 7B and it will be OK. I have tried fall planting and it works OK, just did not bear as much as spring planting. 9B has a later first frost date than we do, so I think that means you should be ok planting now. I'm not sure you guys even have frost in 9B :~).

My guess is the burpee information is for a cooler zone than yours. I pullout out my peas a few weeks back because it was too hot in zone 8. You may want to stick to your successful warm weather crop such as bean, zucchini, and toms. Wait a few month and you can plant peas for fall through spring harvest. I always plant peas in Sept and Oct.