In order to have the perfect lawn, you need to do more than simply water and fertilize the grass. But the truth is, nearly all of the award winning "show lawns" have well prepared subsoil. Without a healthy subsoil, the grass will not stay healthy for as long as it could. And do you want to know a secret? It's pretty darn easy to do! You'll of course want to do this on a new lot before the grass has grown in, or else remove the sod and start over (and depending on your lawns current condition, this may not be a big deal).

If sawdust is used, add a cupful of sulfate of ammonia to each bushel. This is necessary because soil bacteria use up large amounts of nitrogen as they break down the sawdust. If extra nitrogen is not supplied, the bacteria may cause a nitrogen deficiency in the soil.

The best lawn I ever made was based on 3 inches of sawdust (supplemented with sulfate of ammonia), worked into the subsoil six inches deep. Two inches of topsoil over this base gave me a perfect lawn soil for establishing a thick, heavy sod that for four years has never had one drop of artificial irrigation.

Another way to improve the subsoil (but this adds no plant food) is to incorporate sifted cinders that have been allowed to weather over winter before use. These should be sifted through 3/8-inch mesh to get rid of any large lumps. On a heavy clay subsoil, working in a 3-inch layer of sifted cinders will make a remarkable difference in drainage. Be sure they are really worked in and thoroughly mixed with the soil.

In areas where soils are strongly or even moderately acid, lime-stone screenings -- the fine chips used as a top dressing on driveways -- make an excellent subsoil amendment. They can be used on both the subsoil and on the surface. Lime does not make the soil too alkaline until there are fewer than eight clay particles to one of lime.

A word of caution about the use of sand as a soil amendment: Sand is often recommended by garden writers, most of whom probably live where loam soils are prevalent and clay is not a problem ("Loam" is soil composed of sand, silt, and clay in an even concentration, about 40-40-20% concentration respectively). The difficulty is that enough sand to turn heavy clay into a fine, mellow soil would cost a fortune for a sizable lawn. At least one-third as much sand as clay must be in the finished mixture, otherwise the effect of the sand is to act like the aggregate in concrete, with the clay particles acting as the cement. If too little sand is used, the soil will be harder than before.

The cost of sand can be high. In most big cities, washed sand, the only kind available, runs about $5.00 a yard delivered. A heavy clay area, 20 by 50 feet, for example, would require 10 yards of sand.

As you can see, these few methods will prepare your subsoil for a lifetime of great green grass. Now all you have to do is the regular fertilizing and other annual care! You're well on your way to having the best looking lawn on the block.