Just about right now, we start to see moss on lawns and the plaintive cry goes up, "How do we stop it?"

The first thing to understand is that moss is not going to survive in a healthy lawn. The existence of moss is a symptom that the lawn is not in good shape.

Thicken up the turf. Thin grass allows moss to thrive. Apply two pounds of grass seed per thousand square feet of lawn every fall to thicken up the lawn and mow existing turf at the highest mower setting.

Moss also tends to invade lawns with fertility problems so the second thing to do is feed your existing lawn. Ensure it is getting a full two pounds of Nitrogen per thousand square feet and check how to do this on websites or at your favourite garden centre.

Feeding lawns at rates higher than two pounds per square foot tends to produce lush grass that overgrows and is more attractive to insects.

Overfeeding is also a major cause of thatch (note that thatch is another symptom of poor lawn management).

Moss is also created by excessive shade. If shade is the problem, either cut down the trees or substitute ground covers (like moss!) for the grass.

Poor soil drainage is another culprit and this excessive water creates conditions beloved of moss. The solution to this is fairly obvious ? improve the drainage.

Finally, poor compacted soils support moss rather than grass plants. Aeration with a coring machine will help solve this problem as will keeping the lawn roller off the turf.

The short term solution is to apply iron sulfate to the lawn at rates recommended on the labels.

This will "burn" away the moss but the moss will return unless the underlying conditions are remedied.

A healthy lawn will not support moss.

Doug Green is the award winning author of 7 gardening books and the publisher of several ebooks. His home page can be found at http://www.simplegiftsfarm.com and his blog at http://www.simplegiftsfarm.com/gardens-gardening-news.html