miscalculated :(

It is a bit after 5 a.m. and my plan that seemed reasonable last night appears to have been unsuccessful.  Frost was predicted and I covered the tomatoes up near the house (as best I could with the staking) but the ones in the cornfield garden I was hoping that since it was only supposed to get to 33 and only that low close to morning that if I let the sprinklers come on as usual at 5 a.m. that it might protect the tomatoes from potential frost damage.  But when the alarm went off at 5 a quick check of the weather showed the temp already at 31.  I headed out with a flashlight to take a look and the tomatoes look to be done for.  Sigh.