I'm going to focus this week on two actions other than watering, which are vital for the growing of a beautiful lawn in a dry climate. Feeding and scarifying.

Scarifying or "vertical mowing", involves the use of a machine that digs through the grass into about a centimeter or two of the top soil. Most lawns in dry climates are perennials like Kikuyu (Pennisetum clandestinum), varieties of Zoysia or Bermuda grasses. Typically, these species develop a heavy thatch during the growing months, which is a build-up of un-broken down organic material. Left unattended, the thatch reduces the proper exchange of gasses that must take place between the soil and the atmosphere, hinders the infiltration of water into the soil, and by making the lawn mower sink into the grass while mowing, causes the scalping of the lawn. Scarifying is crucial in order to prevent these occurring. And remember -- Poor conditions make for a weaker lawn, which makes for more weeds, pests and diseases.

An alternative to scarifying, not as good but a lot better than nothing, is to shave the grass down to the ground! This should never be done in the winter, is undesirable in the summer, and is best accomplished towards the end of spring.

Warning: These actions only apply to grasses that grow by rhizomes, like the species previously mentioned in this article. Never shave to the ground, grasses that grow by stolons such as, St. Augustine, Buffulo, or "Durban Grass" (Dactyloctenium australe), you'll probably kill the grass if you do!

Some time after scarifying, it's good to feed the lawn. Last week I suggested that the use of compost, humus or any other acceptable, bulky organic material, is highly desirable for your garden beds. For the lawn though, we're trying to reduce the amount of organic build -up in the layer between the soil's surface and the grass stems. Therefore the use of non--bulky material, in the form of either chemical or organic fertilizer is generally preferable to compost, as this can exacerbate the thatch problem. If using chemical fertilizer, I prefer the slow-release types. Although they are more expensive than the readily dissolvable ones like Ammonium Sulphate, they have a number of important advantages:

*Calibration is much easier, reducing the danger of burning off the grass.

*The pollution of the sub-soil water is reduced, due to less leaching of nitrates.

Application can be reduced to twice or three times a year.