Master gardeners: Row cover can save plants from cold (2024)
Q: With all the cold temperatures we have been having lately I have been covering my citrus with an old sheet but my neighbor says that will not protect it from the cold very well and I need something heavier. Is this true?
A. With all the cold temperatures we have had of late it is important to protect citrus and other cold sensitive plants. Your sheet will protect your citrus form damage if temperatures go down to 29 to 30 degrees Fahrenheit. Once they dip below 29 degrees your neighbor is correct in that the thin sheet will not help protect the tree.
If you want better cold protection for your plants and still want something lightweight, try using row cover to wrap the tree. Row covers can protect sensitive plants, depending on the thickness and type of cloth used, down to 24 degrees Fahrenheit. You can inc
rease the effectiveness of lighter weight row cover by using old fashion Christmas lights in the tree in to add some heat in addition to covering the tree.
Row covers can also be used in your vegetable garden to extend your growing season. It keeps wind and pests out, allows moisture in and extends the growing season for your plants. Row covers are less expensive than constructing cold frames, can be stored away in the summer and reused the next season. They are more easily moved around your garden as the seasons change and make an easy to construct shelter for tender plants and will help harden-off seedlings that are directly seeded.
Winter crops like chard, kale, broccoli and carrots do well when they are direct seeded in early February. After you have amended and prepared your planting bed, plant your seeds and then place row cover over the soil surface and secure it. Covers can be secured with landscape staples, rocks or bricks. Or you can purchase a row cover kit. Most kits include hoops, protective film (row cover), fabric clips and staples.
Since the row cover fabric breathes, seedbeds can be watered through the fabric. After germination occurs, remove the row cover or leave it nearby, depending on the weather (or pest pressure), but check regularly to adjust the fabric as needed. Once the plants are growing you will want to use hoops to help raise the fabric over the protected bed so that it is not touching the plants. Mulching with bark, straw or compost is also a good idea in the winter to conserve moisture and discourage weed growth. Thin your new seedling plants as recommended.
Row cover can also be used to protect plants from insects. A successful example of using row covers for this purpose is at the Fair Oaks Horticulture Center where the UC Master Gardeners of Sacramento wanted to protect a cherry tree from the Spotted Wing Drisophola (SWD) pest. They constructed a tent around the tree using Agribon Row Cover. They were able to demonstrate this as an effective cultural method to exclude the harmful SWD pest: no SWD was found on the crop. The cost was $200, it took a few people and ladders to construct the cover, and temperatures were monitored in the hotter months — but this shows one of many creative uses for row cover in the garden or farm.
The Shasta Master Gardeners Program can be reached by phone at 530242-2219 or email mastergardeners@shastacollege.edu. The gardener office is staffed by volunteers trained by the University of California to answer gardeners' questions using information based on scientific research.
Used properly, row cover can provide frost protection in the spring and the fall while also supporting rapid plant establishment and growth. Row cover increases both temperature and humidity under the cover, and the amount of insulation depends on the weight of the row cover.
Row covers are less expensive than constructing cold frames, can be stored away in the summer and reused the next season. They are more easily moved around your garden as the seasons change and make an easy to construct shelter for tender plants and will help harden-off seedlings that are directly seeded.
Depending on the weight of the covering you choose, you can gain between 2 and 8 degrees of frost protection or warm the local environment sufficiently to harvest certain crops a week or two early. You'll get the maximum benefit if the crop is planted on a south-facing slope. Floating row cover protects lettuce plants.
In fact, you can leave plants covered with blankets or sheets for several days without harming them if freezes are likely for several nights in a row. But eventually the covers must be removed so the plants can get light.
Cover the plants with beds sheets, light drop cloths or blankets, row covers (frost blankets), burlap, cheesecloth, etc. Drape the covering over the plants like an umbrella. Anchor the edges down to capture heat from the soil and hold it around the plants, and to some extent, keep frost from settling on the foliage.
Disadvantages Using Floating Row Covers 1) Disposal costs of worn Floating Row Cover material. 2) Weeding under covering requires removal and reinstallation of staples. significantly higher than unprotected crops.
Since the greens don't need to be pollinated, the covers can stay on all summer and into the winter. The greens can often survive our winters without cover, but their dormant time is lessened by the row covers, allowing harvest for an added few weeks.
Heavier-weight row cover gives you a little more frost protection, but less light transmission. I usually use lighter row cover. Place your rocks/bricks over the extra flap of row cover on the ground. This will secure the cover and keep it from blowing away during a winter storm.
Key points. Row covers are synthetic fabrics used to cover garden plants, usually vegetable and strawberry crops, to: Enhance plant growth in spring and fall by increasing the temperature and humidity. Extend the growing season by providing 2- 8 º F.
Properly applied frost cloth can protect your frost sensitive plants from the cold even when the temps dip into the 20s! If necessary, the frost cloth can be left on the plants for an extended period of time without the risk of harming your plants.
Light freeze - 29° to 32° Fahrenheit will kill tender plants. Moderate freeze - 25° to 28° Fahrenheit is widely destructive to most vegetation. Severe or hard freeze - 25° Fahrenheit and colder causes heavy damage to most plants.
Meanwhile, bed sheets work well for covering large plants and shrubs, as well as young sprouts, and newspaper can be used on low-growing foliage, but won't stay on top of large plants as well.
When assessing cold damage on a tender plant, gently feel the root ball by moving the plant to see how loose it has become. A firm, solidly entrenched plant should still have a healthy root system that can recover and support new growth, even if a great deal of the plant's stems or foliage has been damaged.
Bringing plants indoors is the easiest way to protect them from frost or freeze damage. Potted tropical and annual containers can be pulled into a heated room, porch, or into a protected and warm structure, such as a garage, to protect them overnight.
Do not use plastic, such as tarps or plastic sheeting to cover plants. Plastic will transmit cold air to the plants, causing more harm than good. We recommend using cotton fabric or frost cloth to protect plants from frost.
Once temperatures drop below 40°F, you may want to start covering your plants with a frost blanket depending on what you're growing, which we'll get into in just a bit. Freeze – A freeze is when the air temperature is 32°F or below.
Introduction: My name is Stevie Stamm, I am a colorful, sparkling, splendid, vast, open, hilarious, tender person who loves writing and wants to share my knowledge and understanding with you.
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