Before the first hard freeze, old-timers had a simple reflex, French home sites recalled last winter: they reached for their clothespins. The trick costs almost nothing. Here’s what the clothespin is for, and how to use it so your plants actually make it through the night.
In short
- Clothespins hold a frost cover in place over tender plants on freezing nights.
- A cover that shifts or gapes lets cold air in and loses much of its protection.
- Frost cloth can make a difference of 6 to 8 degrees around plants, according to Texas gardening writer Neil Sperry.
- Water the bed first, let the cover reach the soil, and avoid plastic touching the leaves.
What the clothespin is for
The tip appeared in the French press last December, in the Journal des Seniors and on Le Tribunal du Net, which explains it in detail: a clothespin is “slipped onto the edge of a winter fleece, between two stems or around a stake” to hold the fabric. Its job is to block the entry of cold air and keep the cover from shifting in the wind. The point of the article is that the way a cover is fastened matters as much as the fabric itself: a gap or a corner lifted by the wind is enough to let the frost in.
Why the cover has to stay put
A frost cover works by trapping the warmth that rises from the soil at night. That’s why Texas gardening writer Neil Sperry recommends draping the cloth so it “make[s] continuous contact with the soil,” weighting the edges with bricks or rocks, and, where two pieces meet, securing them with clips. Wind is the other enemy: Le Tribunal du Net notes that a loose cover can be lifted or pushed aside, and that’s exactly when cold air gets underneath. Done right, he says, frost cloth “can make a difference of 6 to 8 degrees in the temperature around your plants.”
How to do it
- Water the bed thoroughly before a freeze, as Neil Sperry advises.
- Use lightweight frost cloth. Old sheets and burlap work less well, and sheet plastic is “usually not advisable,” since leaves touching it can burn.
- Drape it to the ground and weight the edges.
- Clip it with clothespins wherever it could lift: where two pieces overlap, around stakes, and between stems.
- Remove it once temperatures moderate on small beds. Larger beds can stay covered longer.
The limit
The clothespin doesn’t protect anything on its own: it only makes the cover work better. Le Tribunal du Net gives no measured results for the trick, and a cover’s few degrees won’t save tender plants from a deep, prolonged freeze. Avoid plastic, and don’t let the cover crush delicate stems.
