Probably the most valuable part of stable manure is the decaying humus in it. Now that the time has passed when every gardener could have his share of stable manure, not only are chemical preparations being made as substitutes for the foodstuffs contained therein, but many firms are offering substitutes, based on some sort of organic waste material, with chemicals added, for the humus content. These are generally good, and can be used freely in the small garden.
They are, however, not so good as a form of humus which every gardener has to hand and which many gardeners waste. I refer to the accumulations of grass clippings, fallen leaves, weeds, cabbage stumps, dead tops of perennial flowers, old stems and leaves of annuals, and so on. Then there are wasted organic materials from the kitchen—parings, tea leaves, bones, and the tops and outer leaves of carrots and cabbages. The bulk of humus which an average small family might accumulate if all these were stored for a year, is very considerable.
An objection is sometimes made to the storing of waste matter, on account of its possible odour, or its unsightliness. There is no need for either. Even the smallest garden ought to be able to spare a small corner for a compost heap. The easy way to make it is to dig out a deep hole, say 4 ft. square and 2 ft. deep, piling the soil excavated round the edge of the hole. This leaves you with about a 4-ft. Pit, and this will be enough for a little garden and household.
All the waste material available that will decay is thrown in from time to time, and over each layer a light dusting of lime or soil. So treated, the heap will decompose gradually without being offensive. Then, when winter digging (or any mid-season digging) is in progress, the contents of the pit will be wheeled to the plot, and buried under the top spit of soil.
A compost pit can be fenced in by a few yards of trellis, which will be covered with some climbing fruits, or in the larger garden the compost pit can be a bricked enclosure in some out-of-the-way part of the grounds, but preferably near to the kitchen garden, where it will be most in demand.
One point concerning the compost pit might be mentioned. A heap of decaying or fermenting vegetation of this kind will lose a good deal of the ammonia by drainings, which seep into the soil. This loss could be prevented by cementing the floor of the pit; but a simpler way, and one which is fairly satisfactory on clay soils, is to puddle the bottom before any rubbish is thrown in. That is, the clay is moistened, and then beaten and pounded to form a solid surface. Clay in a wet state puddles easily and solidly—that, of course, is the reason why clay soils should not be worked much in rainy weather.
OTHER SOURCES OF HUMUS
Other substitutes for stable manure are to be found in various waste materials such as shoddy from mills, spent hops from breweries, and so on. Fish manure is also organic in nature and an adequate substitute for stable manure. Seaweed is still another form of organic manure, which can be used by those who can get it at cheap rates. In all these matters the amateur gardener will be ruled largely by local supplies.
In some districts the corporation collects the contents of dustbins, and converts what is suitable into fertilizer, which is sold at reasonable rates.
A yet further source of humus is to be found in green manure. This method means that the land must lie idle for a part of the year. Rye, mustard, winter spinach, and annual lupins are among the plants grown as green manures. The principle is this. At any time when the ground can lie idle for a while, between crops, seeds are sown and allowed to develop as much as they will, provided they do not actually reach flowering stage. They are dug in, usually when just ready to flower, and decay in the soil to enrich it with humus. A good time to practise green manuring is after an early crop has been gathered, when the seedlings will grow rapidly through the summer and be dug in during winter. Land that becomes vacant in September can be dug over and sown with rye, which will grow large enough to be usefully dug in by March.