By Christina Zawerucha, VINES Community Garden Manager
March 19th, 2021
Don’t shock your crops! You can grow lettuce, cabbage, & spinach in March- but make sure you provide proper cold-weather protection. See vinesgardens.org/calendar
Even though the weather outside is cool, it’s a great time to direct sow or transplant cool-weather crops like peas, lettuce, spinach, radish, cabbage and swiss chard. But we all know how wacky that April weather can be! Make sure you know how to protect your crops from weather fluctuations by using floating row covers, cloches, and cold frames!
A Cloche (pronounced “Kloesh”) is a clear plastic or glass container that gardeners put over a plant to protect it from cold, insects, and rodents. A cloche acts like a mini greenhouse for your plants by trapping and storing the sun’s energy and keeping moisture inside. Just remember to remove the cloche on hot days, or you might accidentally steam your vegetables!
Floating Row Cover
Content Adapted from the University of Maryland Cooperative Extension
Light weight FRC (left), Heavy and light weight FRC (right)
Floating row cover (FRC) is a white, light-weight, non-woven fabric made from spun-bonded polyester or polypropylene. It has a “gauze-like” appearance that allows sun and moisture in, while also keeping insects and cold weather out. Simply drape it over and enclose plants like a blanket, and secure it to the ground with heavy rocks or landscape staples. The cover “floats” directly on top of the crop, like a protective blanket.. The growing plants push the cover up, if you give it enough slack. Alternatively, you can erect simple frames to support FRC above your plants. Air, sunlight, and water can penetrate the material.
Why use it?
- Frost protection in the spring and fall due to increased temperature under the cover.
- More rapid plant establishment and growth in the spring and fall due to increased temperature and humidity under the cover.
- Creates a shield around your plants keeping insects, rabbits, deer, birds, and groundhogs from feeding on your plants.
- Relatively inexpensive at 2.5 to 4 cents/sq. ft. Can be re-used two to three years.
What kind of row cover should I buy?
Floating row cover is available in many widths, lengths, and weights:
- Heavy-weight FRCs (1.5-2.2 oz./sq. yd.) are usually used to extend the growing season in spring and fall, allow 50%-70% light transmittance, and 4º-10ºF. of frost protection.
- Light-weight FRCs (around .5 oz./sq. yard) are marketed as “insect barriers,” have 90%-95% light transmittance, 2º-6ºF. of frost protection, and can be left on many crops (e.g., beets, snap beans, salad greens) from seeding to harvest.
Would you like to purchase some Floating Row Cover Materials for your garden? VINES offers a Season Extension Kit for a suggested $8-10 donation that is designed to cover you standard 4’x10’ raised garden bed. Contact firstname.lastname@example.org or call 607-323-3171 to place your order.
Large quantities come on a bolt; cut to size with scissors.
Small quantities can sometimes be found in retail stores.
How do I use it?
FRC can be draped directly over plants and held to the ground with rocks, boards, bricks, or sod pins
Leave enough slack in the row cover so that growing plants can push it up. This works well for single rows of plants (e.g., broccoli) or wide rows or beds (e.g., lettuce, spinach, Asian greens).
Build a re-usable frame from wood, pvc pipe, #9 wire, or other available materials to support FRC. This works well for single rows of tomato, pepper, and eggplant.
Fall greens under FRC
Nice low tunnel at a Kent Co. school garden protecting spring crops
WHAT ARE COLD FRAMES?
Adapted from the Old Farmer’s Almanac.
At their simplest, cold frames are bottomless boxes that are set over plants in the garden to protect them from adverse weather. They are usually built low to the ground and have a transparent roof to let in light and a hinge for easy access.
WHY USE A COLD FRAME?
Cold frames protect plants from strong winds and retain heat. Gardeners use cold frames to extend their gardening season—both in the autumn to protect plants for a few more weeks and in the spring to get a jumpstart on sowing seeds. Cold frames are also used to “harden off” seedlings that were started indoors.
- Try sowing seeds of crops such as radish, lettuce, endive, and scallions directly in the frame for an early or late harvest.
- You can even raise them there all summer as long as the cover is removed when warm weather arrives.
- Consider growing winter lettuces or other salad greens, like spinach or kale.
HOW TO MAKE A COLD FRAME
Cold frames can be bought or constructed from timber and plastic, but concrete blocks or bricks can also be used. You can even construct a simple, bottomless wooden box and set it in the garden or atop other good soil in a sunny location. Watch our video, below, for step-by-step building instructions!
Cold Frame Building Tips
- Most gardeners use wood to build the frame, since it’s readily available and is easy to cut to the required size using hand tools. If you’re lucky enough to find scraps of hardwood, then use this, as it will last longer than softwood.
- Avoid old wood that’s been treated with creosote or similar non-earth-friendly products, especially if you’ll be positioning the cold frame directly on the soil. The wood can always be painted with a non-toxic paint if you’re worried about it looking scruffy.
- Top the box either with glass (perhaps an old storm window) or a frame covered with clear plastic. Thicker materials will provide more insulation, of course. Old windows and shower doors are classic subjects for this project. Hinge the cover or add a sliding lid so that it may be opened for ventilation on warm days.
- If you have high-sided raised beds, you could add a sheet of glass on top to construct a temporary cold frame.