Question
HI, i just had a few questions about growing seedlings.  I have planted seedlings a long time ago and most were about 3-7 inches tall depending on the type of seedling.  Well one day i decided to put them outside the temp. was about 60-70 degrees F. i was just wondering what is the lowest temperature seedlings will be able to handle?  One day it got down to i think 40F and after that i lost quite a bit of seedlings, so i brought out the portable greenhouses and now they are all in a small greenhouse.  What would be the lowest temperature they could handle in a greenhouse?  THis is my first year growing flowers from seed and i have grown more than 200 plants but now i think im about to 165-175.  Thanks.

Answer
Hi Dustin,
Thanx for your question.  First of all, when you take seedlings grown indoors, outdoors, they need a chance to adjust to the brighter light and more extreme environment than the protected environment from indoors.  Temps depend upon what kind of seedlings you're taking outdoors.  My tomato, eggplant and pepper seedlings will tolerate temps in the 40s at night as long as they are 3 or 4 inches tall and have been hardened off properly.  Hardening off means taking seedlings outdoors and placing them in the shade, protected from direct sunlight, wind, rain, etc. for about 10 days.  After that, they can be put in the direct sunlight.  Many annual seedlings don't do well if the temps while not freezing are too cool.  Let me know what kind of seedlings you have and I'll try to give you a better answer.  In general though, perennials from zone 5-9 will tolerate temps down to the mid 30s if they are protected from the wind and rain.  Many annuals do not like temps to fall below 45 degrees before they start showing negative effects.  I hope this helps.
Tom