I've started them in late February in Alpine 4500ft elev. But it's a real struggle until the soil temperature reaches 60F which doesn't happen here until about late March. To start a month early requires warming the soil with a mini greenhouse. Also helps to have black plastic or weed barrier on the soil surface.

My best method for extra early is black surface and clear poly over that. Once the plants are up keep it below 100F by day and as warm as possible at night. So ventilation of the clear poly is essential on sunny days.

A black weed barrier or black poly, plastc, is a huge plus for weed control.

When your average of the high and low air temp reaches 60F, the soil should also. That would be a good time to plant.

Houston reaches ave air temp of 60F about Febr 20. So you could plant now with soil warming or in a month to 6 weeks without.

With all out effort I can advance melon first harvest by 4-6 weeks. But around here that requires careful attention until last frost usually in April but 24F in May last year. I did harvest a watermelon in June last year with 24F in May and a brutal hailstorm in June. But it was a lot of work and most were lost to the hail, all except one area covered with hail netting.

This post was edited by fruitnut on Sat, Jan 11, 14 at 15:45