Spring frosts can spell disaster for the go-gettin’ gardener. If you plant out early but offer no protection for your seedlings, a quick dip in the mercury can set you back weeks.
As the weather turns towards spring, eager gardeners can't be blamed for wanting to get a jump start on the season. After all, the growing season for Western Washington is only so long. But spring weather can be unpredictable and overnight freezes are not uncommon in the Northwest.
If the forecast calls for evening temperatures below 40 degrees Fahrenheit, offer your plants some protection. The difference of a few degrees can save tender annuals and even frost-sensitive buds on fruiting bushes. In the morning, or when the weather warms, remove the covers to increase air flow and let in light.
Now let’s get growing, gardeners!
Natural Burlap Landscape Fabric
Burlap works well with trees, flowering shrubs and other upright perennials. It also makes a good insulating wrap for potted plants. The material is natural and biodegradable, but it’s not the best option for letting in sun.
A thinner, more tightly woven material than burlap, Harvest Guard fabric traps heat and allows for photosynthesis. The cover "floats" over plants with no additional structures. Consider adding weights on windy days.
Perforated plastic mulches help keep heat and moisture in the soil. That’s great when it’s hot and dry, but less useful for above-ground protection. Use mulch film when there’s more sun, and a ton of growing to be done.
Water tubes trap heat during the day; the fleece-lined, breathable cover insulates while letting in light; the whole thing folds back to allow full access to meagre spring sunshine. It’s more to install, but the frost protection is unbeatable.
Somewhat more of a sun hat than snow cap, the waxed-paper cloche protects tender vines from sun scald and traps heat. Very useful for encouraging early growth, and can be torn to let in more light and release moisture once plants get going.
It’s reusable, recyclable and protects from frost, freeze and sun. It’s a win to the fourth power if you consider that it’s one of the few covers that is nearly square, rather than row-sized. It’s also porous for better air circulation and letting in rain.
Milk jugs work well—you just have to do some prep work. This includes a good washing (Who enjoys rancid milk smell?) and cutting off the bottom to create an opening. Why not cut off the top? Later on, it may be useful to remove the jug’s lid to release trapped heat and moisture.
The French have long used bell-shaped jars in the garden. Glass or terracotta jars, called cloche à salade, protected leafy greens from frost and wind. You can make something similar out of upturned terracotta pots. Clean them first with hot water and soap, and remove during the day to provide light.
Blankets or sheets
If you’re in a plant-mergency, look no further than the linen closet. While not the best option, cotton sheets or a light blanket can offer some protection from the cold. Unlike garden fabric however, rain could seriously weigh down your covers and harm seedlings beneath.