USE OF MANURE, 63 



each 4-inch pot. The application was made to six cultures, contain- 

 ing altogether 156 plants, exactly comparable with a similar number 

 of plants receiving no manure Avater. The a implications were made 

 in April and May and varied in number from five to eight. 



In all six cultures the plants to which manure w\ater had been 

 applied made a more vigorous growth, temporarily at least, than 

 those that received none. 



Similar results were secured by the use of one-tenth cow manure, 

 freshly rotted, in the peat mixture in which the plants were potted. 



It was after the beneficial eftect of this manuring had begun to 

 show itself that a statement of similar results nearly a century old, 

 in the culture of heaths, came to the writer's attention. It is con- 

 tained in a book by AVilliam McNab entitled "A Treatise on the 

 Propagation. Cultivation, and General Treatment of Cape Heaths." 

 published in 1832. The original is now rare, but a reprint was pub- 

 lished in 1908 in Notes from the Royal Botanic Garden, Edinburgh, 

 volume 3. pages 351 to 374. McNab, who was the superintendent 

 of the Edinburgh garden from 1810 to 1848, was undoubtedly the 

 most intelligently successful grower of Cape heaths at the period 

 of their greatest popularity. His treatise is original and practical 

 and delightfully written. ^^Ith reference to the manuring of lieaths 

 he states: 



I may mention that i have used a small quantity of manure in tlie foregoing 

 compost with very good eftect, about one-eighth part of cow dung. This should 

 be well rotted before it is used. The way that I have always prepared this 

 dung before using it is to take a barrow load of it and place it in thin layers 

 between layers of peat earth, and after it has lain for some time, chop the 

 whole up together, and turn it over at intervals till the dung disappears and 

 the whole mass assumes the appearance of black peat earth and sand: and 

 where this manure is applied about an equal quantity of sand should be added 

 (that is, about one-eighth part of the whole) iu addition to the sand that I 

 have before recommended to be mixed up with the earth. This, I know, can be 

 used with very good effect, but for all ordinary purposes I consider it quite 

 unnecessary, as there is no difficulty in growing heaths very soon too large for 

 the accommodation that is generally allotted for them, with the compost that 

 I have mentioned witliout maniu'e. T merely mention this because I know it 

 is the opinion of some that heaths will not thrive with manure added to the 

 peat earth in which they are grown. 



I know, however, that some heaths may be grown to a larger size, in the same 

 space of time, with manure than without it; but, as I have already mentioned, 

 I consider it quite unnecessary for all ordinary purjioses. and any person who 

 wislies to try its effects ishould do so very sparingly at first, till he is enabled 

 to judge of the eftect produced l\v it. as a little excess of manure is sure to 

 injure the ])Iants. I*erliai)s liquid manure might be used with very good effect 

 for growing some kinds of heaths, bvit I am unable to give any particular direc- 

 tions in what projiortion it should be used, as. from what trials I have made, I 

 can not come to any certain conclusion. But this much I know, that whoever 

 wishes to try it should do so at first with great caution, with quite as much as 

 in using an excess of manui'e in its solid state. 

 193 



