Season extension questions!

Unfortunately, Jemm, there is no magic formula as to when we should add or remove row covers, or change it from frost cover to plastic cover, or vice versa. There are so many factors involved in those decisions, not the least of which is what you are growing in the bed. For example, there are some crops which are frost resistant, and do not need covering, while other crops are very sensitive to cold temps. How long to keep on the frost cover, before replacing with plastic depends on the rating of the frost cloth. For example, AG-19 offers 4ºF of frost protection, while AG-30 offers 6ºF of protection, and AG-50 offers 8ºF of protection. That means that if you have a cover of AG-19, you can safely keep plants from freezing down to temps of 28ºF, or if you have AG-50, you can safely keep plants from freezing down to 24ºF. How much are you willing to gamble on the plants freezing?

As for plastic covering, I tend to put that on early -- an ounce of prevention thing -- rather than waiting to be surprised by an early frost or freeze.  BUT, and a very important but, is if you put plastic on the hoops you MUST be prepared to open the tunnel during the day, and closing it in the evening. If you forget to open it one day you will bake the plants in the heat of the day, and if you forget to close one evening you will loose the plants to freezing.  And then, of course, there are days in the winter when you cannot open it because the temps will remain near zero, and there are days in the fall and spring when you cannot close it because the temps will in the 50's or higher throughout the nights.

The best advice I can give is carefully watch the weather and adjust accordingly. And, keep a daily journal showing what the high and low temps are, the condition of the hoops are, and the results. Next year you will find that journal worth its weight in compost!

Thank you, OhioGardener...much as I dislike numbers, these are helpful! Everything in the bed is definitely cold tolerant to some extent. I think I'll put the frost cloth on...and order my plastic ASAP. I guess a downside of having plastic on is the need to water too.