The Secret Life of Wintry Roots

A practice that may seem counterintuitive but truly isn’t controversial… is watering plant roots (especially the immature or containerized) before the big freezes. At first thought, this may sound like the last thing you’d want to do when temperatures are about to drop below 32°F. Wouldn’t that promote more issues with ice surrounding the plants’ roots? 

Well, from a physics and plant anatomy standpoint, here is what is really happening… Firstly, moist soil acts as a heat reservoir and subsequently is a better root insulator. Think about an airy, dry, cracked soil and how easily cold air can penetrate and drop temperatures of the surrounding roots. Saturated ground fills those gaps and slows that cooling process.

The other thing to consider beyond the insulation is that a well-hydrated plant is more tuned to handle a freeze. A briefing on the anatomy: a hydrated plant’s cells are undergoing turgor pressure, or fluid pressing on the walls of the cell. Think of those plumped up cells as more resistant to collapse and membrane damage. An empty, dehydrated plant cell is prone to a harsh collapse when freezing and thawing occurs. And that’s that! Watering isn’t some kind of catch-all superpower when it freezes, but it’s a valuable tool for everyone to be considering. It’s a way to buffer temperature swings.

A couple of notes on HOW to water:

• Water the root zone, try not to hit any living foliage.
• If you water in the morning, the afternoon sun is going to warm up that saturated soil and offer a bank of that heat reservoir for the upcoming cold temps.