You don't need row covers for lettuce and broccoli at those temperatures. My hoophouse temps get down to the 30s and occasionally the 20s overnight. Forty and 50-degree lows are child's play for those kinds of plants.

Put 'em in the ground NOW. Your biggest threat now is that they will not mature before the hot weather sets in. Cold is their friend--heat is their enemy.

Thanks Ralleia. They're going in the ground this weekend. Still trying to get them hardened off.

Row covers are something of a luxury unless you are having real problems with flying insects or frequent frost. You should be fine with transplanting in the open air.

Dana, row covers are wonderful in our part of the country during the fall and winter season. They protect all the brassicas (cabbage, kale, broccoli, etc.) from cabbage loopers, worms that eat their leaves to lace, AND they protect your crops from our brand of cold weather. When I plant my winter garden, I put the row covers over hoops over the beds from day one. I have had them protect lettuce down to eleven degrees. In other words, I use them as a "mini greenhouse" so to speak.

This time of year, they are not necessary, unless, of course, you want to protect them from insects.

They are also helpful in the summer for insect protection, but they do prevent pollinators from getting to blooms....

Use the row covers but for warm season stuff like squash and tomatoes.