Garden: The gathering moss on your lawn

Jane in Olivebridge has moss growing in her lawn. Mosses, like most lawn weeds, primarily take advantage of bare areas but do not kill existing grass, as some people believe. Bare areas in lawns can result from several causes. Unsuitable grass varieties, poor drainage, drought, soil compaction, excessive shade, thatch accumulation, poor fertility, diseases, improper mowing and other cultural practices are common reasons for turf failure leading to moss or other weed problems. Improving these factors to encourage thick, healthy grass is the key to long-term prevention.

Moss can be killed with products containing ferrous sulfate, ferrous ammonium sulfate and a variety of lawn fertilizers with moss control; or moss- and algae-killing soaps. None of these materials poses serious threats to the environment; in fact, iron and sulfur are essential nutrients for grasses and tend to improve their color. Although these products will kill existing moss, unless the underlying conditions are changed, moss or other weeds are likely to reappear.

Raising the soil pH with agricultural or dolomitic lime can improve availability of nutrients and supply calcium, thus helping the turf grow better but will not kill moss directly. The following steps will generally control existing moss and discourage it in the future:

1. Use a moss control product to kill existing moss in late winter or early spring.

2. De-thatch or rake out dead moss, or skip step 1 and dethatch or rake with more vigor.

3. Overseed bare areas with the recommended turf type for your area.

4. Top-dress seeds with about ¼ inch of loose weed-free soil, or potting mix.

5. Keep seeded area moist until seedlings are established.

Julie in High Falls wants to grow a moss garden.

While considered by some to be a pest, mosses have both ecological and aesthetic value. A good bio-indicator of air and water pollution, these hardy, yet delicate, plants thrive only in areas that exhibit good air and water quality. They are also one of the first plants to respond to acid rain; the decline in mosses (and other related plants, such as lichens) indicate a negative change in the environment. Moss acts as a great erosion control and helps retain moisture and nutrients in the soil.

Aesthetically, mosses add a natural beauty to the lawn and garden setting, typically filling in void spaces of soil where little else will grow. So, if moss is already growing on your property, you're off to a good start. Its presence indicates that environmental conditions are favorable for moss to grow and that little or no site preparation is necessary. For a weak lawn with moss present, simply remove the grass by hand or chemically, and let the moss take over.

The first thing that is needed to grow a moss is a shady area. Look at the landscape and try to obtain a moss that is growing in conditions as close as possible to the area where moss is wanted. Different varieties of moss will survive in different degrees of shade, but all mosses need some level of shade.

Mosses also generally grow in damp areas and, for the most part, need that acidic soil. One way to speed up the growth of the moss (obtained either on your own property or from someone else's with their permission or by purchasing it) is to make a moss slurry.

With a moss slurry, it's possible to cover a large area faster, but it will take a few weeks to more than a month to really become established. To make the slurry, mix two parts moss, two parts water, and one part buttermilk in a blender. Blend thoroughly and then spread the mixture over the area where you would like the moss to grow.

Keep misted with water (never let it dry out completely) until the moss has established itself.

Dona Crawford is the master gardener coordinator at Cornell Cooperative Extension of Ulster County.