150 Commercial Gardening 



soil, the value of which is well known to all gardeners who cultivate pot 

 plants of any description. But the leaves and stems of such crops as 

 Potatoes, Carrots, Parsnips, Turnips, Beet, Mangel, Peas, Beans, Jerusalem 

 Artichokes, and the stems of many Cabbage crops, &c., are often available 

 as vegetable refuse, and may be utilized to improve the soil. The quantities 

 of leaves and stems vary according to the different crops, but the following 

 is a fairly approximate estimate per acre of some. Beet, 15 tons; Cabbage 

 crops, 7 tons; Jerusalem Artichokes, 13 tons; Turnips, 12 tons; Potatoes, 

 6 tons; Parsnips, 10 tons; Apples, Pears, and Plums, 4 tons. 



Vegetable refuse of this description, as well as the clippings of hedges, 

 the dead stems and leaves from flower borders, &c., makes an excellent 

 fertilizing material for the soil. It may be utilized in a green or raw 

 state whenever the ground is being trenched, or in a decomposed state as 

 a compost when digging or ploughing. Many market gardeners and 

 farmers are well aware of the value of this material and take advantage 

 of it. 



The only danger to be apprehended is in the case of Potato stalks and 

 clubrooted Cabbages. These contain terrible fungoid diseases, and it is 

 generally safer to have them burned than dug into the soil. Although 

 burning will drive off all the organic foods, the ashes left behind will con- 

 tain valuable fertilizing salts that may be dug in afterwards. 



Roots as a Manure. Besides the overground stems and leaves of 

 crops, one must not forget the roots. Although many crops are said to 

 be cleared off the ground, the fact remains that a very large quantity 

 of fibrous roots of all crops are left behind in the soil; and the more 

 rudely the plants are taken up the larger the quantity of roots left 

 behind. This may be easily seen by pulling up a cabbage or a lettuce 

 by hand, and comparing the roots attached with those on similar plants 

 that have been carefully lifted with a fork. As the roots decay they 

 become humus and have all the fertilizing value of that organic material. 

 It has been estimated that in an acre of grass land at Rothamsted there 

 were over 4J tons (10,400 Ib.) of roots in the soil at 9 in. deep; and these 

 roots contained 78 Ib. of nitrogen to the acre. 



It will thus be seen that, even if stable manure and artificial fertilizers 

 are excluded altogether, very large supplies of plant foods may still be 

 secured from the waste leaves, stems, and roots of the crops themselves. 

 It is therefore wise to take a leaf out of the book of the Continental, as 

 well as the Chinese and Japanese cultivators, and avoid wasting the 

 vegetable remains of any crop. If they are burned or thrown away, it 

 is equivalent to wasting valuable supplies of nitrates, potash, phosphoric 

 acid, lime, sulphur, soda, magnesia, and other plant foods, for which high 

 prices will have to be paid. 



Guano. This is a valuable manure, consisting chiefly of the dried 

 excrements and waste of sea birds, which have accumulated for centuries 

 on the coasts and rainless districts of Chili and Peru. The famous 

 traveller Humboldt first brought samples of guano to Europe in 1804, 



