It just depends on the weather...
Yes, I'm kidding. In my zone the last week of May is pretty much good for anything. I've sewn zinnia seed and planted tomatoes, cukes, zucchini, and peppers as late as the third week of June. Leaf lettuce, greens, herbs. Good returns on everything. I'd never use that as a guideline but I've seen it work , Memorial Day makes a pretty good calendar event .
Happy growing!
