Watering Overwintered Plants

Q. I'm having trouble figuring out how to water the plants I'm overwintering in my garage. They're an odd collection of perennials such as salvia, tender plants such as patchouli and rabbit-foot fern, and sedums that I just haven't gotten around to planting in the ground yet. There's a little bit of light coming in through high windows, and the temperature stays in the 40s.

A. As you probably already know, plants use less water as growth, temperatures and light plummet, and it's very easy to drown the root systems.

In general, the soil for the plants should be moist but definitely not wet. How often you'll need to water to achieve that will vary according to the type of plant.

For plants that are dormant, you may not need to water them but only sparingly until spring, assuming that you first put the plants in the garage in a healthily moist state. Check the soil of each plant with your finger to test whether it needs water, and keep the soil at the moisture level suitable for that particular plant (for sedums, for example, keep the soil on the slightly dry side). Plants that still have their leaves will probably use a bit more water, but again, be sure to check the soil before adding any water. You may find that you'll need to water only once a month or even once every two months. During any periods of thaw in the winter, when temperatures moderate outside (and therefore in your garage), you may need to check the plants more often.