Franny, don't know the numbers, but I would cover the new veggies the next couple of nights. I'll leave it to someone else to answer the peony question.

Thanks Rosie!

Weather forecasts, when they talk of overnight lows, are for measurements taken 4 to 5 feet off the ground.

Plant tissues will freeze in the 30 to 32 F range (not usually right at 32 since only PURE water freezes at 32.0 F). Plant cells have ions and impurities in them to cause the actual freezing temperature to drop, to say, 30.5 ot 31.2 F, etc.

When weather forecasts call for nighttime temps in the 35 to 40 F range, frost IS possible. Not at those particular temps, but because that's the low predicted at the heights where the official thermometer qequipment is (4-5 feet off the ground). COlder/coldest air sinks and is at the ground surface -- where your plants are.