Humus is added by plowing into the land vegetable matter which is in condition to rot quickly and become thoroughly mixed with the soil. Rye, clover, cornstalks, vines or other garden waste, and manure, are commonly used. Manure that contains a large proportion of stable litter and sweepings, and street sweepings, are especially rich in humus, and are much sought after by experienced gardeners. By adding them, the texture of the soil is lightened and improved, made loose and mellow so as to hold moisture, and is at the same time prevented from caking. Moreover, humus contains plant food and heat that make seed sprouting easy. The amateur gardener seldom recognizes the importance of the physical texture of the soil, but the best results demand the best conditions. Unless you want to grow pears and plums—which thrive in clayey soil—break up the clayey earth and improve its texture in every way. Your garden will repay you, and you won’t go about denouncing those who have written books about the possibilities of small areas as wilful deceivers of the guileless and unwary. Get it firmly fixed in your mind to start with, that, if your garden does not yield adequate returns upon your labor, the fault is yours. You are working unintelligently, and deserve no more than you are getting. To know your soil is to be able to give it the treatment it needs to make it fruitful. CHAPTER III. SOIL FERTILITY. Soil fertility is the power in the soil itself to produce a good crop under proper conditions. Man can neither make nor destroy the land. All that man can do is to make it more or less efficient, according to how he uses it. Two men may take two pieces of soil of equal fertility and get vastly different results; by careful study and experiment we may learn how to take advantage of this fertility; but the real secret of it, Nature has wisely locked up in the soil itself, so that one generation of men cannot really rob the next. It has been said that old-time farmers, of New England particularly, robbed the soil of its fertility, so that their sons have been compelled to abandon the old farms and seek new land in the west, or new occupations in the cities of the country. The real truth is, not that the soil has been robbed of its fertility by the fathers, but that the sons have continued the unenlightened methods of the fathers even after their ineffectualness has been proved.