It could. Many plants suffer chill injury at temps that high, especially if the temperature falls rapidly. Covering, as Bob suggests, helps trap the warmer earth's heat and helps moderate temps under the cover significantly. covering works best if the cover goes all the way to the ground, all around the pots. It's too late now, but for next time chill is expected, slightly drought stressed plants are less susceptible to chill injury. Al

Well I planted them anyway (as well as my zuchinni, and yellow squash) because I seeded them way too early and didn't want to wait any longer for increased risk of transplant shock. Besides I have a backup batch just in case. I guess it was better to seed more than I knew that I would need after all. My soil temp today in my raised beds was 66F and the air temp was approaching 80F with a moderate amount of humidity. Not bad considering the long-overdue rain in the Northeast most likely cooled the soil a few degrees. Will report back on Tuesday with my results, fingers crossed. BTW, if the forecast calls for cooler temps than low 40s what if the quickest way to cover them with something commonly found in a house? I posted two videos in another thread today ("will my veggies drown") so you can get an idea of my garden setup and the size of my seedlings (not even sure I can still call them that).

They should germinate when sunlight, moisture and soil temperature combine to trigger germination as long as they haven't been eaten by critters, blown away by wind or washed away by heavy rain. I grow perennials from seed via winter sowing to protect them from predators and bad weather. There is a winter sowing forum here on GardenWeb where you can find out more about the method. This is my container ghetto: These are a few of my 2011 sprouts:

I'll share my little invention that I use in my citrus. I start with a glass jar candle, like the little ones that are on restaurant tables sometimes. The one's I use are about 2 1/2 inches across and 3 inches tall. Next I take a 1 pound coffee can with one end out, the regular way you open a coffee can. Then I punch several holes in the sides. I'd say about 6 neat the top (end with the end still in) and 6 two thirds of the way down. This is with the open end as the bottom so it can sit over the candle. I set these out, with a little stick, maybe the size of a pencil, under one side so that the can is tipped. This lets a little more air flow through the can and gives air to the candle. The cans do a couple of things. First, when it's 30 degrees out, the candle wax will be so cold that the wick will burn a tunnel right down through the candle and most of the wax won't burn. So the can keeps enough heat in that the wax can melt and the candle burns the way it should. Next they act as little radiators. The idea here is to heat a lot of air just a little. The heat from a candle by it's self would all just go straight up and not help the tree. They also keep the candle from blowing out in a light breeze. I do this with about 120 candles for 100 citrus trees. Of course being out at 2:00 in the morning, freezing my fingers, lighting candles, is not a lot of fun, but it is a rather pretty sight. Be careful for fire hazzard. Do not place on or near mulch, branches, or other flammables. Clear a spot so that they are clear of any material that can burn. Do NOT put these directly under the tree as that will be to much head and will "burn" them. If you do this, you should monitor them closely. I will put a movie on, make hot tea, set a timer, and check them once per hour after I have them set. I got all my citrus through last years hard freeze. We had 2 days of more than 12 hours of below freezing temps with a low of 10! and 2 more days with lows of 12 and 15. Nasty cold for citrus. The limes didn't fruit this year (the trees are ok though) but everything else did. I also run irrigation water while doing this. the heat from the water helps too. Start irrigation water early, several hours before the temp drops below freezing, to build heat in that area. If you wait until it starts to freeze, it's to late.