February 23, 1907 



HORTICULTURE, 



223 



Rooting Medium for Orchids 



In HoRTicuLTUKE, Jan. 19th, Mr. 

 Orpet revives the old question of 

 the best medium for orchid? and 

 takes his usual side-shot at tlio advo- 

 cates of leaf soil. Mr. Orpet has 

 by his wonderful success in the cul- 

 tivation of orchids, which he at- 

 tributes in part to the use of brown 

 osmunda fibre, converted many to 

 his belief that osmunda fibre is the 

 very best medium. Mr. Orpet, as a 

 successful cultivator, is so well 

 known that anytliing he says is gen- 

 erally accepted and although most 

 of his advice is good I do not think 

 he is quite fair in his remarlis' con- 

 cerning leaf soil. An impartial 

 view of the matter may not be out of place. 



Few cultivators entirely agree upon the question of 

 compost. Some succeed with fern fibre alone, others, 

 and I may say, the great majority, use fern fibre and 

 moss and many, Mr. Orpet notwithstanding, still favor 

 leaf soil. For many species the safest and most durable 

 rooting medium is good, soft, brown, osmunda fibre 

 without moss. The physical properties of this material 

 counterbalance its deficiency in plant food which can 

 be supplied as needed, and by the liberal use of Cook- 

 son's formula at the right time large and healthy 

 growths may be obtained. 



For many species and especially Odontoglossum 

 crispum and kindred species leaf soil, if properly 

 handled is an excellent medium. Some splendid speci- 

 mens have been grown in it and I may also add, many 

 plants have died in it. Where special attention can be 

 given to watering it is the very best but where such is 

 not jjossible it is the very worst. 



Eoot aeration is as necessary to all orchids as a pure 

 atmosphere, and in a mass of material like leaf soil a 

 complete change of air is only produced by driving out 

 the air in the pot by a thorough watering and allowing 

 the phints to become comparatively dry before watering 

 again and as leaf soil dries very slowly it will be seen 

 how easy it is to i>roduce stagnation by too frequent 

 watering. Larger growths will be made in leaf soil 

 than in any other medium under the sun and providing 

 enough light is given to mature what has been made 

 larger flower spikes and increased vigor will be the 

 result. The outcry against leaf soil was that many 

 growths did not flower and those which did did not 

 have the lasting qualities of flowers produced by the 

 use of peat or fern fibre. This is entirely due to insuf- 

 ficient light to mature the growths. The use of leaf 

 soil has become more general in England in spite of 

 the outcry against it, but it is most frequently used in 

 mixture with peat. The osmunda fibre does not lend 

 itself to mixture so well as English peat as it is far more 



Cattleta labiata 

 After two years In leaf soli. 



easily demoralized by contact with moisture or decaying 

 material. 



In tlie December number of the Orchid Review an 

 eminent orchidist describes a visit to an orchid estab- 

 lishment in the North of England and after describing 

 the position, style and eccentric mode of ventilating the 

 odontoglossum houses, which, according to orthodox 

 ideas, should be enough to kill any odontoglossum, says 

 that the medium used is a mixture of moss and leaf soil 

 (the worst combination on earth) which is used Tvithout 

 drainage; then he tells of the vigor and health of the 

 plants concluding by giving dimensions which are 

 almost incredible. I wish Mr. Orpet could see our 

 odontoglossums which have been in pure leaf soil about 

 sixteen months. The increased size of the pseudo- 

 bulbs just finished and the vigor of the new growths, 

 also the size of the numerous flower spikes would 

 delight him I am sure. During the hot weather they 

 showed no signs of distress; the roots were as healthy 

 afterwards as they could possibly be in fern root. For 

 cattleyas and Iselias leaf soil is an excellent medium 

 although for sickly plants I prefer osmunda fibre. 



Cypripediums and masdevallias take kindly to leaf 

 soil, l3ut in a house where the shading is permanent 

 they will not flower so well although when enough light 

 can be given they flower better. Cattleyas, laelias, mas- 

 devallias and odontoglossums in leaf soil can stand more 

 direct sunlight without harm than the same subjects in 

 fern fibre. 



Our Frontispiece 



Our frontispiece shows a house of healthy specimens 

 in bloom of Cattleya Mossise, Cattleya Mendelii, Den- 

 drobium thyrsitlorum, Miltonia vexillaria and Laelia 

 purpurata. John Nilan, the grower, is a frequent con- 

 tributor and prize winner at the exhibitions of the 

 Massachusetts Horticultural Society. 



