These are averages so a frost could come a few weeks earlier or later than the stated dates. Deeper valleys tend to have frost conditions earlier than the surrounding area since cold air sinks.
Most vegetables and herbs need to be harvested before the first frost, which will turn them brown or mushy. But all frosts are not created equal. A 29 to 32 degree frost may only damage the leaves, inhibiting their ability to photosynthesize. The second frost might not come for another few weeks allowing a little more harvest time. A killing frost is 28 degrees or below.
Some vegetables actually improve after a frost. These include kale, cabbage, parsnips, carrots, beets, and brussels sprouts. Frosty weather helps the starch in the root turn to sugar so they taste sweeter.
You can often over-winter these vegetables by simply covering the bed with a thick layer of straw. The mulch will help protect the plants and hold the warmth of the earth in. These methods are also called season extension!
When you want something fresh for dinner during the winter, you scrape the straw aside and harvest what you need. Replace the straw and you can enjoy fresh veggies all winter.
Article Written by: Angie Lavezzo
About the Author: Angie Lavezzo is the former general manager of Sow True Seed. Beyond her professional role at Sow True, Angie's passion for gardening extends into personal hands-on experience, fostering plants and reaping bountiful harvests.