The value of this liquid as a stimulant of vegetation does not appear to be generally appreciated by our agriculturists, many of whom make no use of it. In a state of incipient putridity, soap suds is replete with the element of vegetables, in a state of actual and complete solution ; the only condition, indeed, in which it is susceptible of absorption and assimilation by the roots of plants. Besides its value as a powerful stimulant, it possesses, also, very potent anthelmintic properties, and when used in the irrigation of garden and field crops—the best way, perhaps, in which it can be applied to vegetables—operates as a remedy against the ravages of bugs worms, &c. Every farmer should have a large tank or vat, capable of holding from three to four cart-loads, it should be constructed in some place easy of access, and to which, without difficulty, the wash from the sink and laundry can be regularly conveyed. In this reservoir all the wash matter produced on the farm should be thrown—bones, retuse, ashes, muck turf, rich soil, and chip manure from the woodshed ; in short, every substance capable of absorbing the rich fertilizing liquid, and retaining it for the benefit of the soil on which it is to be applied. Nature has everywhere supplied in munificent abundance, the means of fertility, and we have only to appropriate and apply them judiciously, to secure the best and most flattering results. Some agricultural writers have estimated the value of a hogshead of suds, in a state of incipient putridity, to be very nearly equal to that of a cord of prepared manure, but as its value depends entirely on the grease or fatty acids, and the soda or potash of which it is composed, non-nitrogenous materials, its virtues may be over-estimated.
This article was originally published with the title "Soap Suds as a Fertilizer" in Scientific American 8, 44, 346 (July 1853)