I had no Watermelon last year. It evaded me all season long.
I found a planter to raid up in NC in late Sept, and we had no time to stop.
The ones I have grown from seed are Carefree mix, Wizard mix, and one other. They germinate overnight and then just shuffle along for months.
eskinola grows alot of her collected seeds so she will know more than I do.
When propagating is so easy from cuttings I nixed growing from seed unless it was for hybridizing my own coleus.
Hope this helps.
Sidney
