Fall is almost upon us, so it is time to start planning for how you are going to extend those garden crops for as long as possible through the frost season (see the before picture on the right). Helping your vegetables survive through fall means a longer growing season and money saved in the bank. There are two types of frosts to be aware of. Advective Frosts are plant killers; very cold temperatures that drop below plant hardiness levels. Radiation Frosts are survivable for your plants if they are covered and generally represent the frosts most likely to occur in early fall.
Below are three super-easy ways to help save your crops from a radiation type of frost. Advective frosts are tough to fight and you might need more powerful protection tools. All the below concepts involve covering the crop and trapping the heat of the soil beneath the covering. These coverings work as long as they do not get wet. A wet cover makes the temperatures surrounding the plant cooler.
1. Blanket and Sheet Covers
These are the simplest to use. Simply toss a lightweight blanket or sheet over the area of garden you are trying to protect. I have been known to use all the blankets in my house and ask my neighbors for theirs, but have had regular success in saving the garden for many weeks if there is only a one or two night frost situation; the covers help the plants survive those two nights in order to enjoy the Indian Summer later in the fall. Be sure to remove the blanket in the morning so the plants receive sunlight and warmth during the day.
2. Floating Row Crop Covers
Floating covers keep frost and insects off the plants, but allow daylight to provide enough light for growth. Depending on the plant, you can leave the row cover up all day without a problem. Do not forget to water the plants that are beneath the floating row covers.
3. Plastic and Garden Covers
Plastic covers work, particularly if you have a supportive frame to cover the planting bed. If you like, you can add lights at night to increase warmth within the protective frame. In the top photo you see the miniature greenhouse garden cover I have placed over my raised beds from Greenland Gardener. The garden cover is easy to assemble – it took me less than 15 minutes to put this together and place it properly. Unfold, assemble support pole, place in position, tighten Velcro (see photo below), tie the poles together at the top, place over beds, and DONE!
According the FTC, I need to let you know that I received products in this story at no cost in exchange for reviewing them. They worked well and I am happy about that.
Better Gardener, Gardening, Products | Tags:
advective, blankets, crop cover, floating row, floating row crop cover, frost, frosts, garden, Gardening, greenhouse, ground cover, killing frost, plastic, radiation, Shawna Coronado, Soil
It isn’t pretty. Three successive nights of freezing temperatures in my yard have taken their toll on a landscape far advanced beyond its normal stage of growth for this time of year due to an unseasonably warm March. At first glance things don’t look too bad. The creeping phloxes are still blooming their hearts out; the Bloomerang lilac sports its fragrant blossoms next to the deck; and the overall effect is one of a lush, green landscape. But look a little closer, and you can see the damage.
I expected some injury to plants. With several thousand different perennials, trees and shrubs in my half-acre yard, I simply couldn’t protect them all. With the exception of tender annuals and tropicals that I covered with floating row covers, moved into the garage or crowded onto the front porch and deck, everything else had to fend for itself through the freezing weather. I’m unsure of the exact low temperatures the past three nights. However, a nearby weather station reported 28 degrees F the first night, and it was supposedly a few degrees colder the second night. This morning the yard was covered in white once again.
Some of the plants showing frost damage were predictable. Saucer magnolias often get nipped by late frosts here in the Midwest. True to form, ‘Jane’ magnolia was injured in this freeze cycle. But because she was already done blooming, it was her leaves that turned brown and limp rather than her gorgeous pink blooms. Leaves of butterfly bushes and caryopteris often curl with the first frost of fall; they did so this spring too.
Other injured plants were more surprising. Chrysanthemums withstand fall frosts with ease, blooming through early autumn cold snaps. But their tender new shoots in spring are quite sensitive to the cold. In some instances, damage may be due to microclimates in the yard. My ‘Miss Canada’ Preston lilac was totally trashed (see photo below), while all other lilacs escaped unscathed. Of the dozen or so daylilies in the yard only one showed injury. ‘Strawberry Candy’ developed bleached leaves where frost settled on top of the plant.
I conducted an inventory of damaged plants, dividing them into “severely damaged” and “lightly damaged” categories. Severely damaged plants showed extensive wilting, browning and/or dieback. Lightly damaged plants included those that had a few wilted shoots, nipped leaf tips or slight discoloration. Of course, these are somewhat arbitrary divisions, but I’m including the lists here for you to compare damage in your yard or to help you know which plants are most sensitive, and need protection the next time freezes arrive.
‘Jane’ magnolia – sweetbay magnolia was OK
Blue mist spirea (Caryopteris) – all varieties in the yard
Deutzia – ‘Chardonnay Pearls’ and ‘Pink’, virtually all foliage blackened
‘Miss Canada’ Preston lilac (Syringa) – all other lilacs undamaged
Ginkgo (Ginkgo biloba)
Butterfly bush (Buddleja) – all varieties
Endless Summer hydrangea – other mopheads also affected; paniculata types except Little Lime unaffected
Astilbe – all varieties
Hardy kiwi (Actinidia)
Chrysanthemum – half a dozen varieties burned back
Kamtschatka sedum (Sedum kamtschaticum) – a dozen other sedum species and varieties mostly unaffected
Japanese anemone – all leaves blackened
Rose of Sharon (Hibiscus syriacus)
Strawberry – open blossoms blackened; foliage unscathed
Purple flamegrass (Miscanthus purpurascens) – almost all new shoots browned
Russian sage (Perovskia) – all shoots wilted and drooping
Lemon balm – a few brown leaves
St. Johnswort (Hypericum) – shrubby kinds OK; herbaceous types show some wilting
Jupiter’s beard (Centranthus) – a few damaged leaves
Boxwood (Buxus) – only one variety out of four had wilted stem tips
Weigela – only one variety affected the fist night; several more damaged the second night
Mukdenia – outer leaves browned
Lungwort (Pulmonaria) – some damaged leaves
Calamint (Calamintha) – half of shoots affected
Crape myrtle (Lagerstroemia) – only a few new shoots damaged
Lily (Lilium) – one or two varieties of the dozen in the yard showed watersoaked leaves
Rose (Rosa) – Pink Double Knock Out and Deja Blue had wilted new shoots; more than a dozen other types OK
‘Purple Pygmy’ agastache – half a dozen other agastaches had no damage
Itoh peony – a few bronzed and wilted leaves
Beautyberry (Callicarpa) – a few new shoot nipped
Japanese painted fern (Athyrium) – some browned leaves
‘Sarastro’ campanula – half a dozen other campanulas were fine; this one was wilted
Dwarf goatsbeard (Aruncus) – browned foliage
Japanese toad lily (Tricyrtis) – watersoaked foliage
Leadwort (Ceratostigma) – some browned foliage
Lavender (Lavandula) – one variety with wilted tips; half a dozen others OK
‘Rozanne’ geranium – a few wilted stems
‘Strawberry Candy’ daylily (Hemerocallis) – bleached foliage
Winterberry holly (Ilex) – new growth browned; also some damage to blue holly
Chinese cabbage – some bleached leaves; they had been transplanted outdoors just a week earlier
The official low temperature this morning was 41 degrees F in Des Moines, but the frost on the narrowleaf zinnias, at left, prooves that it was colder in my yard. My home is in a frost pocket, despite its location at the top of a hill. Every time the weather forecast calls for “scattered frost”, it’s a sure bet that ice crystals will develop on exposed plants.
Last night I prepared for the cold by moving container gardens under the deck canopy, onto the front porch, or into the garage. I also pulled out the floating row covers to protect tomatoes, peppers, and some of the more cold-sensitive bedding plants, such as coleus. But Christo-draping the yard with fabric can only go so far. Inevitably, some annuals remain unprotected.
I may have salvaged some of the uncovered flowers by watering them early this morning before sunrise. After melting the ice out of the hose, I sprayed water on the icy plants to melt the frost. If the ice crystals were only on the surface of the blooms, this may be enough to rescue the frosty flowers. I hope so. I’d like to get another month of color from them. Mid-September is simply too early to call it quits on the gardening season, don’t you agree?