Is it time to plant Tomatoes yet?

These seedlings are hungry to get into the ground, and you are excited to put them there, but is it time to plant them outside? The most important thing to watch is the low nighttime temperatures.  Frost data tables for the Philadelphia region suggest that we can still get temperatures low enough to harm or kill tomato seedlings, even into May.  Fruiting plants in the Solanaceae family (tomatoes, eggplant, and peppers) really don't like to be subjected to temps below 50 degrees. Wide temperature fluctuations when plants are still seedlings causes stress to the plant which usually results in a slower growth rate.

Whether you decide to plant a little early or after the projected frost free date of May 15th, there is a process by which you should toughen a plant up to withstand low nighttime drops, called "hardening off."  This simply involves putting your plants outside while they are still seedlings in the sprouting container like the ones pictured above. At first, put the plants out for a few hours each day increasing the amount of time they are outside each successive day and after a few days they will be ready to be left out overnight.  Even the relatively small changes in temperature experienced this way should help to toughen up then new plants.  As long as the temperature stays above 55 at night its fine leave them out by their lonesome with no cover.  Once they are in the ground, they can still be protected from cooler temps (below 50) by covering them with a thin plastic tarp, paper bag, or upside down bucket.   Happy planting!