As stated in Chapter VI (Lawns) (Lawns), mulching is the best means of preserving a steady degree of moisture in the soil and of keeping it at an even temperature. It also prevents the soil from cracking and proves beneficial on account of its substance being washed into the soil by rains or artificial waterings; in fact, there is no practice more beneficial to newly planted trees or plants, of almost any kind, than a good mulching, especially in a climate like ours. It saves much labor in watering, and, as has just been stated, is the best means of preserving a uniform degree of moisture in the soil surrounding the root. This is emphasized by repetition, as it is a most important point and, other things being equal, plants will languish or thrive just in proportion as this condition is secured.
Although mulching is apparently a very simple operation, it must be carefully done. Before mulching a newly planted tree, the soil should be shaped in the form of a basin, the rim of which is extended one foot beyond the extremity of the roots. The rim should be three or four inches higher than the bottom of the basin so that rain or water applied artificially will be retained. The mulch should be kept at least three inches away from the stem of the tree.
The best mulch for trees is half-decomposed stable-manure, which should be spread about three inches thick and levelled evenly; about half an inch of soil should be spread over the manure to keep it from shifting in event of heavy wind. Where stable-manure cannot be had, half-rotted tree-leaves, short grass cuttings and even tan-bark are suitable.
The practise of mulching may be carried into the flower-beds, as well as to the trees and shrubs. The writer has personally found the mulching of flowering plants to be of great value. The soil is not compressed by water nor baked into a crust by the sun; evaporation is arrested and the growth materially increased.
In mulching flowering plants the material to be used should be well-rotted stable-manure or thoroughly decomposed leaf-coil and should not be spread more thickly on the surface than one-half inch.
The mulching of lawns should be also very carefully done. Owing to the continuous, heavy, artificial watering necessary in our dry climate, mulching is of great benefit both in preserving the health and vigor of the grass and in preventing evaporation. July is the best month for doing this. After about two months of watering with the hose or sprinkler, the soil will be found to have become hard and washed looking while the small roots of the grass will be partially exposed thus necessarily requiring more frequent and more copious watering. The best mulch for a lawn in this condition is a covering of about one-half inch of well-rotted stable-manure spread evenly over the entire surface of the lawn. This will give a soft springy surface and renewed life and growth to the grass while its color will become much darker. It will not then require nearly so much water to keep fresh and vigorous.
Mulching newly sown grass or other seeds means spreading a thin layer of clean, fresh straw over the surface of the ground, its purpose being to shade the ground until the seeds germinate. The straw should be raked off when the grass is one inch high.