The maintenance of lawns consists of fertilizing, rolling, watering, and mowing in order to keep the turf in such condition that few if any weeds will have an opportunity to flourish. Fertilizing of a lawn is perhaps one of the most important items of its maintenance, for the reason that few lawns are so well prepared when first made that they do not begin to need additional food material during the second or third year after making. It is difficult to convince those who are developing lawns for the first time that money expended in the proper preparation and fertilization of a good depth of topsoil will do away with the subsequent annual expense necessary to keep a lawn, not correctly prepared when originally made, in the best condition. A good turf requires food in the form of fertilizer, and this food supply must either be provided at the time the lawn is made or it must be constantly applied from year to year afterward (See Page 53). Much thought, labour, and money are wasted in putting a mulch on lawns, only to come back later and cast it away again. It may be wise to mulch a lawn in the fall, but there is more than an even chance that if the area is covered with fresh manure, weeds will be introduced and this will more than offset any real value derived from the mulch. The use of manure as a top-dressing for lawns should be discouraged unless used in the form of a completely decomposed compost. A thick coat of manure is apt to stifle the grass. Lawns should never be mulched with manure during the spring unless with thoroughly rotted manure applied not later than early March. All mulching or top-dressing should be done preferably in the fall so that the weed seeds are killed to a great extent during the winter. It is practically useless to apply the manure on frozen ground, for an ensuing rain or melting of the snow may dissolve and carry away either in solution or suspension most of the fertilizing ingredients.
Bone meal alone, especially if not very finely ground, may be used in the late fall at the rate of five hundred pounds an acre, or twelve pounds to 1,000 square feet every year. Bone meal seems to be the best phosphoric acid carrier for lawns. Nitrate of soda is the quickest-acting fertilizer and may be used broadcast in quantities up to five hundred pounds an acre each year. This quantity must be divided among two or three separate applications. Both blue grass and clover will be encouraged by the use of air-slaked lime as a winter dressing every four or five years, at the rate of one ton an acre. Chemical fertilizers are best applied in the spring as a top-dressing and about five hundred pounds an acre should be applied. A mixture of 5% nitrogen, 6% available phosphoric acid, and 8% potash will produce good results. Equal parts of finely ground bone meal and sifted wood ashes at the rate of one ton an acre make a good spring top-dressing. Kiln-dried sheep manure may be used at the rate of one ton an acre or fifty pounds to 1,000 square feet, with excellent results, with the assurance that it will not bring in weed seeds. It should be applied in early spring for the best results.
A properly prepared lawn will not require much watering unless the season is unusually dry or near-by trees are robbing the grass roots. In any event, a few thorough soakings are much more valuable than many superficial sprinklings. The effect of a good thorough soaking is not only more lasting in itself, but also encourages deep rooting of the grass, which, in turn, tends to remove the necessity for watering and also opens up new stores of plant food to the grass roots. It is better to avoid all spray nozzles and whirligig fountains, for, however handsome the effects they may produce in the sunlight, they do not insure a thorough soaking. It does not matter nearly so much at what time of the day a lawn is wet as it does how thoroughly the watering is done. Watering done in the middle of a hot, sunny day, however, is made less effective by reason of evaporation. It also involves some scorching or cooking of the blades of grass as the sun shines through the globules or film of moisture upon them. Do not hasten to sprinkle a lawn at the first approach of warm weather as this will discourage the tendency of the grass roots to go deeper in search of the ground water. If the lawn shows signs later in the season of being in distress, give it a thorough soaking. An effective watering should soak the ground to a depth of five or six inches.