According to historical weather records, the summer of 2020 in Southwest Virginia has been 5-10 degrees hotter on any given day than the average of previous years. As we look into the next few days’ weather forecast, it reminds us that a trend can always be upset and the weather can never truly be predicted.
With temperatures moving close to freezing well before the first frost date of the season around the 3rd week of October depending on your region, we are facing the opposite problem of the heat we faced during the height of the summer.
While we shouldn’t be too worried about frost damage in the 3rd week of September as the ground temperature is still quite warm, it does remind us that colder temperatures are right around the corner. Fortunately, we have multiple ways to fend against the cold weather and make sure we keep up production well into the Fall.
Cold Frames and Hot Beds
These structures are generally made out of wooden boxes surrounding the crop or garden with window panes for the sun to penetrate and heat up. These are quite popular as they can be made up of many materials on hand. A cold frame should be oriented towards the south to capture as much sun throughout the day as possible. Keep in mind that these structures will heat up tremendously if the temperatures get very hot and they can damage plants in some cases if you aren’t careful.
Perhaps the most versatile but most expensive options are high tunnels. These are large structures made of plastic or metal purlins draped in various thicknesses of polyethylene plastic. The translucent plastic allows heat to come into the space and traps it within. Because these structures can be many different sizes, they are great for growing many different crops in any needed configurations. Cold weather crops can be grown well into the winter months with a properly constructed high tunnel.
Row coves are a fairly recent development and have gained a lot of attention as they inexpensive and allow for quick and easy setup with great benefits. They are made with a woven fabric material that is draped over short hoops of wire every couple of feet. They should be just slightly wider than the row itself and not much taller than the crop that is growing. The benefit is that they are good for reducing the impact of temperatures by 4-5 degrees. This means that the effective frost temperature can be reduced to as low as 28 degrees. This provides excellent protection for late October and November nights where frosts can be present.
There are many options available for quick and easy protection against cold weather. Check out our Virginia Cooperative Extension publication for more options and diagrams of the different methods mentioned here. https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/426/426-381/426-381_pdf.pdf
Be sure to reach out to your local Master Gardener Help Desk for help determining which solution is right for you and which crops can be grown in cold weather. Roanoke County Master Gardener Help Desk (540) 776-7178 | [email protected]
– Evan O’Neill – Extension Agent, Agriculture and Natural Resources