This section is from the book "The Gardener's Monthly And Horticulturist V21", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
Although I am not a believer in feeding plants with raw flesh, I am of a different opinion as regards the vapor from ammonia, having employed it years ago in various plant houses with good results by sprinkling the floors and filling the evaporating troughs on hot water pipes with strong liquid manure, when the houses were shut up in the afternoon.
I used it in vineries, peach houses, cucumber and melon houses, and pine stoves, and also in Orchid houses. In all cases it improved the color and size of the leaves, and also the fruit and flowers. Of course, it requires discretion as to time of using it. I employed it during the time of most vigorous growth, not when the fruit was ripening or the plants in flower.
There is nothing new in my plan, for many years ago, before hot water was employed for heating houses, excellent cucumbers and pineapples were grown by the heat of fermenting manure, in which the ammonia generated acted no small part. There was far less trouble then to keep down red spider and thrips, than since fire heat has been generally used, and the crops were generally good; in fact, one of the best crops of melons and pineapples I ever saw was in the Royal Garden at Frogmore, grown by dung heat. No doubt the regular moisture given off by this system did much towards success, but the vapor being charged with ammonia was the secret.
The direct feeding of raw meat to the foliage is much like the principle advocated many years ago of burning dead horses in new vine borders. For a time the results appeared in wonderful foliage and large fruit; but when the carrion became decomposed, all the roots decayed and the border became a soapy mass, through which no air or warmth could pass, and the vines and borders had to be removed. I removed one such border, and saw the results. No doubt some will say that this is not a parallel case to feeding plants through the leaves; but my experience with Dionaea has been that when a large insect was caught and began to decay, the leaves which held the insect decayed also; and when a number of flies, etc., were caught in Sarracenias and Darlingtonias, they decayed the pitchers, for I have had a number of large plants spoiled for the season from this cause.