It appears to be April 15. Not sure when was it this spring. It was colder....

First and last frost dates can be very localized; a few miles, or less, and many other factors can make a difference. We had a cold winter and a cool, late spring this year.

That being said, April 15 is a pretty close date to work with.

However air temperature isn't the only factor to consider. Soil temperature is important, too, for seed germination as well as root and plant growth. For warm-weather crops like tomatoes and peppers, might as well wait until the soil warms to at least 55-60 degrees F, since if the soil is too cool the plants will just sit and sulk until it warms up enough for them to get some root activity going.

Somewhere I read that the old way of determining when the soil was warm enough for planting was for the farmer to drop his drawers and sit down. Probably not a good idea for most of us.

Here is a link that might be useful: Interactive NJ Last Frost Date Map

I'll try to explore planting with black soil cover. We had a weak tomato season. Was the summer cold?

Weather gurus are saying this summer was a normal summer; that previous summers had been warmer than usual.

That being said, I've heard mixed reviews on tomato production this year, especially while on Helpline duty at the County Fair - some people said it was a great year, others said it was a poor one. Might have been a difference in the varieties they planted and/or very localized environmental conditions.

Remember that, although tomatoes like warm weather, they won't set fruit if daytime temperatures go above 92F ... or below 55F at night.