About the SFMGA

Saturday, April 26, 2008

All about roots

by Janet Hirons, Master Gardener

Most plants absorb very little moisture through their leaves. Almost all the water they need has to get absorbed through their roots. So the more roots they have, the better equipped they are to find and absorb moisture. A well-developed root system with lots of little sponge-like root hairs is a plant's best insurance for survival in drought conditions.

Rainbows and butterflies, cattails and dandelions, waterfalls and rainforests, puppy dogs and dragonflies, sea foam and orcas, sunshine and comets, snowflakes and ice cycles, wildflowers and gardens. The universe thinks of everything.

For a plant to develop a good root system, the roots need to be able to push out into the soil. And to do that, they need to be working in a loose, friable soil—not one that is hard and compacted. Gardeners can help create good conditions for root growth by breaking up hard-packed soil mechanically and/or by adding organic matter. Mixing organic matter in with native soil loosens up the soil and makes it much easier for roots to move in all directions.

Organic matter—such as compost, peat moss, and shredded leaves—makes soil more porous, reducing runoff and helping soil retain water, making more moisture available to roots for a longer time.

Absorbing moisture is the task of the youngest, most tender part of a plants root system—the rooting tips and root hairs. When moisture conditions alternate radically between wet and dry, these root hairs get stressed and damaged. Covering the soil surface with a thick layer of mulch reduces water loss due evaporation, and just as importantly, helps maintain a consistent moisture level in the soil to keep delicate root hairs healthy.