Question
Hey Mike,  We live in upstate NY. I've been here all my 58 years, my wife is from dixieland. The usual last frost date here is around may 1 but it can be as late as may 30. Last year it was May 27, but in 2006 the last frost was April 14. We are starting veggies early inside this year to extend the season. I may have started too early a week ago as the lettace is already up to 3". Tomatoes are just sprouting. Other things will be started soon.
   After the sprouts get going I plan to move them to bigger pots until I can get them outside. My question regards the cold and frost outside. We have an unheated porch that has a roof with only screening on the walls. If we move the seedlings out there in april, when the days get above 50, will the night frost kill them even though there is a roof?? My thinking is that since the roof is there, the frost can not settle on them. Many people plant their Tomato seedlings in the garden in early May and then cover them when frost is predicted. So I figured its not the cold air but only the frost itself thats the issue. Therefore if they are on the porch after the days get to 50+, the frost at night won't be an issue.??
Also if we leave them to grow inside is there a problem with indoor air when they get bigger?
My wife, being from dixie, planted tomatoes in late April outside last year and the frost killed them in late May. She had a fit, "ya'll ain't got no time up here. Down home we get Tomatoes by June." Well this isn't Kentucky.
    I see Tomatoes in pots for sale in April that are knee high. So I was planning on getting them about that high by May 1 by putting them on the porch. Currently there is 32" of snow in the yard as of March 19. Deeper in the woods. It won't all be gone in the garden until April 25 or so.
  Green Bell Peppers....is it best to plant them in some shade or all sun? Planted in an area with sun from 2 p.m. to sunset last year but they did not do well. Cucumbers in the same area did fantastic had 500 Cukes.
    my dixie chick insists on having Cantelope. Last year they did very poor even though I bought prestarted plants. They were next to the Cukes but did poor. Info on Cantelopes???
   Our iceberg lettace did well but never headed up. Why??  
    I have a very rich soil but its only 10" deep. Gravel under that.
   The porch has a roof but only screening from floor to roof. On the outside of the porch I have the clear plastic I put on for the winter. It get lots of sunlight. Will the plastic sheeting help keep the frost away?

Answer
Wayne, you should not place your plants outdoors before your last frost unless you have a cold frame. These enclosures will protect plants for up to 10 degrees. The fact that the porch has a roof will not save the plants. Even a light frost will kill tomatoes and peppers. Hardy plants such as lettuce and broccoli will sustain a few degrees below freezing, but it is still not worth the risk.

I start all of my plants based on the timelines outlined in the attached website. The second link will give you your exact frost dates.

http://www.victoryseeds.com/information/plantingdates.html

http://www.thegardenhelper.com/hardiness.htm

The general rule of thumb is 6 weeks prior to your last expected frost, but I always extend it two weeks due to the uncertainty of the weather in the NE portion of the country. As you said, some years you may get lucky, but more times than not, we get that last frost sometime past the expected date.

You can certainly keep the plants indoors as long as they get sufficient light. I use fluorescent bulbs, and keep them no further than 3" from the top of the seedlings. I then transition them outdoors after the last frost date by hardening them off slowly, usually over a one week period. This acclimates them to the outdoor conditions.

I hope this answered your question. Please write again if I can ever be of assistance.

Regards,

Mike