Hi, Elizabeth. I was reading the how-to growing instructions on one such variety from Johnny’s, to see if it offered any other hints. One thing it suggests is doing successions of each variety to figure out the timing for your spot, so staggered sowings/transplantings (and some record-keeping I guess!). In striving for the right timing (as opposed to just wanting a successive harvest with a crop whose timing you already know, like repeat sowings of lettuce) I’d probably do the successions every week or 10 days (not 3 week apart as for harvest-stretching). It does sound like you will have to push these a bit later and have some protection on hand or October/November but maybe even like 2 weeks’ delay will do it and you’ll only need some fabrics row cover at the far end? One other suggestion: DO you have any local farmstands or farm markets where any of the farmers grow it? (E.g., Mx Morningstar Farm in Claverack NY does). What about asking a nearby farmer what their start dates are that are working best?

I should add I also put a shade cover over all these crops to try and prevent them from growing too vigorously.