122 



Effects of Charcoal on Vegetation. 



Vol. VII. 



Effects of Charcoal on Vegetation. 



Some of the gardeners and scientific men 

 of Germany, have within a i'ew years inte- 

 rested themselves in a series of experiments 

 upon this subject, conducted at the royal bo- 

 tanic gardens of Munich, by Edward Lucas, 

 of Erfurt, assistant gardener. The results 

 are highly curious, and may probably be 

 turned to good account by cultivators in this 

 country. Professor Zuccarini, of Munich, 

 mentions that by the use of charcoal, shoots 

 of plants, leaves, parts of leaves, calyces, 

 &c, may be made to grow, even of plants 

 that seldom or never make roots in the usual 

 way of treatment. 



He states that Lucas, in the spring of 1839, 

 discovered that several plants in a hot-house 

 that were plunged in refuse of charcoal, 

 showed an extraordinary vigor of growth, 

 as soon as they had pushed their roots 

 through the holes in the bottom of the pots, 

 into this under stratum. This observation 

 led to a set of experiments, which quite 

 astonished himself and the scientific friends 

 who encouraged him to prosecute them. 



He at first used the refuse of charcoal, 

 too fine to be burnt, from which he sifted 

 the coarser pieces by a coarse earth sieve. 

 He found that to answer best which had 

 been exposed for some months to the influ- 

 ence of the air and weather. In such char- 

 coal, unmixed with any other material, he 

 succeeded the first season in getting cut- 

 tings of many plants to grow; he names 

 sixty-six kinds; among them, P]uphorbias, 

 Begonias, Cacti, and other succulent plants, 

 black pepper and the bread fruit. The un- 

 successful experiments were few, compared 

 with the successful. From parts of leaves, 

 he succeeded in getting a considerable va- 

 riety of plants to vegetate; he enumerates 

 twenty-nine, including a species of Euphor- 

 bia, two of Begonia, and the sweet potatoe. 

 All the species of Gloxinia grew, even from 

 a flower stem, or a calyx. A species of 

 pine (Pinus excelsa,) grew from the leaves. 



He then mixed various kinds of earth 

 with the charcoal, and still had the most ex- 

 traordinary results. He says that all the 

 plants he subjected to this treatment, were 

 as much distinguished by their luxuriance, 

 as by the more perfect developnment of their 

 individual parts. This was particularly the 

 case with tuberous rooted plants, which be- 

 sides their perfect developement, had also a 

 much longer period of vegetation ; so that 

 the difference in this respect, between those 

 that were cultivated in their usual soil, and 

 those which had a mixture of charcoal, 

 amounted to nearly two months. Orange 

 trees with yellow leaves, having had a layer 



of charcoal laid on after the upper surface 

 of earth had been removed, soon recovered 

 their green colour; this was also the case 

 with some other plants. He was not very 

 particular as to the proportion of earth he 

 mixed with charcoal, but generally found 

 half of each to do very well, always taking 

 care that the coal had been exposed for 

 some time to the weather, and that timely 

 watering was never neglected, as the po- 

 rosity of the earth causes it to dry quickly. 

 An old and sickly plant of the Doryanthes 

 excelsa, which had been declining for two 

 years, and had no roots left but one old and 

 decayed one, was planted in one third char- 

 coal. In three weeks it began to grow, and 

 finally recovered perfectly. 



Lucas, in an essay written within a year, 

 mentions that many gardeners not having 

 succeeded in their experiments, charcoal had 

 fallen into disrepute among them; but he be- 

 lieves that in every case the failure was ow- 

 ing to the manner of applying it, or to the 

 quality of the coal itself. He has found that 

 in many cases, particularly when used in 

 pots, as soon as the capillary vessels of the 

 charcoal are full, a further supply of water 

 is useless and injurious; when mixed with 

 soil, however, it requires more frequent wa- 

 tering. But the chief cause of failure was 

 the fineness of the charcoal, by which its 

 most valuable qualities, capillarity, capabili- 

 ty of condensing gases, and porosity, were 

 lost. 



Many new plants, of which he names 

 seventy-two, some very difficult sorts to root, 

 had grown in charcoal, since his last pub- 

 lished essay. He mentions four kinds of 

 magnolia, a myrtle, Canada pine, Indian 

 azalea, an erica, the tendrils of a grape, 

 the oleander, and two kinds of medicinal 

 guaiacum. Among the plants he names, 

 are species of the most opposite families, 

 and most of them rooted much easier than 

 in sand or earth ; with some, no trial of the 

 usual methods of propagating had before 

 been successful at the botanic garden of 

 Munich. He had not made much use of 

 charcoal in sowing seeds, but when applied, 

 it had proved very efficacious. He had made 

 experiments upon the fitness of charcoal for 

 packing plants for transportation; and for 

 this purpose some young chamcedoreas, ferns, 

 calceolarias, salvias, verbenas and young cab- 

 bage and cucumber plants, some with moss 

 round the routs, others without any cover- 

 inii, were put in dry or very slightly moist- 

 ened charcoal, firmly pressed down, and the 

 closed box placed for four weeks in an airy 

 shed, on which the sun shone for several 

 hours; at the expiration of this period, the 

 palms and ferns were found in a very fresh 



