Many discussions here about this and I have linked some of them below. You'll also find several on-going discussions on its use, advantages and disadvantages over on the Soil & Mulch forum.

That said, timing of application is crucial as you discovered. Organic mulches are generally more beneficial but can't be applied until after the soil has warmed up first.

If you opt to use the plastic - be sure it is an actual mulching plastic with air and water holes in it, not solid plastic - don't pull it up, cover it with organic mulch and leave in place to keep the root cool in mid-summer.

Dave

http://forums.gardenweb.com/forums/load/txgard/msg051248164720.html

http://forums.gardenweb.com/forums/load/wisconsin/msg121147285884.html

http://forums.gardenweb.com/forums/load/giants/msg0607064417571.html

http://forums.gardenweb.com/forums/load/prof/msg091140145826.html

http://forums.gardenweb.com/forums/load/mngard/msg0113062929742.html

We actually topped the garden with black weed stop, over organic mulch. We cut holes for each tomato plant. We are in WA, along puget sound, so we don't get extreme heat in the summer. We were VERY late planting our garden this year, for various reasons, but we had beautiful, quick growth and we are still harvesting tomatoes on live plants. Not to mention, there were almost no weeds. Had a cold scare the other night and covered with tarps overnight...cold didn't harm a thing.

I used black plastic all season long and my plants are all over 7' tall and they are still growing like crazy will post pics tomorrow. I live in Mich. and my toms are still green and very productive not one weed all year. The whole garden was covered in plastic.

Dale

I used black plastic and it worked great. I never even moved over to organic mulch - but then again, we don't have extreme heat temperatures here.

Virtually no weeding, raised soil temperatures, and no slugs (heat off the plastic seemed to kill them before they made it to the plant).

For holes I just took a hand rake and poked holes wherever puddles developed. Seemed to work just fine, and in fact, the plastic kept the soil underneath it quite moist.

In your area, I don't see it as helpful or necessary to apply plastic mulch to warm up the soil or to hold off on putting down organic mulches. An exception would be if you were planning on planting mid-Feb or earlier.

Soil temperature doesn't get that cold, and should be plenty warm enough for planting tomatoes when you need to. I'm not saying putting down plastic early is going to hurt if you want to try it, but I'm wondering if you didn't plant too late to get good fruit set.

What date did you plant? What varieties did you grow?