11 
The great variation in the mineral elements contained in. 
vanilla vines which have been planted at the same time in the 
same way in exactly the same soil, does not show any clear re¬ 
sults of manuring by the analysis of the vines and it has been 
decided next year (1918) to start manuring on a large scale on 
estate plantations in order to determine the influence of the 
manure on the yield of the orchid without taking into account 
the variation in the composition of the vines (extensive plots). 
But a curious feature of the analysis is the relative percen¬ 
tage of mineral matter (ash), water and organic matter found 
i 2 i the vine. 
Dry matter o/o . 10.20 
Water o/o . 89,80 
100.00 
TA j., r Mineral matter o/o of green vine 
tDrganic matter 
as compared in the composition of grasr * ^ 
1.23 
8.97 
Dry matter o/o 14.30 
Water o/o 85.70 
Dry Matter 
100.00 
f Mineral matter o/o of green grass ...1.89 
\Organic matter o/o ” ” ...12,41 
As the amount of Vanilla vine under good conditions of 
growth can he reckoned at a weight per acre which is nearly 
equivalent to a crop of grass (2 tons) one is entitled to deduce 
that the elements absorbed by vanilla from the air and from the 
soil (substratum) is nearly equivalent to the amount of food 
materials required by ordinary herbaceous plants. 
Vanilla being a vine of considerable length and power of 
growth it is in many ways different from the ordinary orchids 
which only grow a few centimetres per aimum and require only 
a few grammes of food elements for their growth. 
Cattleya bulbs for example only contain 0-5 o/o of mineral 
matter instead of 1‘21 o/o as in vanilla. Although the proportion 
of organic matter and dry matter is about the same as in vanilla 
it is therefore evident that the conclusions arrived at in Europe 
for the treatment of orchids may not apply with the same force 
to the culture of vanilla in the tropics. 
Many orchids growers in Europe are very reluctant to em¬ 
ploy chemical manures and also organic manures such as cowdung 
which bring about decay of the roots of the plants. A few spe¬ 
cialists however have lately started employing mineral salts in 
solution with success and the best orchids growers are of opinion 
now that being given a good fibrous and porous soil where the 
delicate plants are rooted their growth is singularly improved by 
weak solutions of ammonium nitrate and ammonium phosphate. 
If this is so for ordinary orchids which contain such a small 
amount of mineral matter, it is evident that it applies with more 
force to the more exacting vanilla plants which no doubt in the 
natural state find a larger amount of plant food in the decayed 
organic matter which abounds in the crevices of the rocks and 
dead woods on which they grow as well as in the rain water of 
the tropics when so much nitrogen in the form of nitrates is found 
during the storms. 
These facts should not be lost sight of for the proper treat¬ 
ment of vanilla vines and for the improvement of the soil. 
Alternate layers of dry grasses, earth and lime, no doubt 
create the best medium for the growth of the oi’chid. It is not 
the lime alone which is responsible for the beneficial action but 
the combination of lime and grasses and earth (especially garden 
soil and burnt earth) which help to form that black mould which 
is so common in countries where decayed plants are mixed up 
with coral (lime) deposits. 
Lime by itself is much dreaded by orchid growers in Europe, 
water containing lime being rejected for watering purposes, but 
the behaviour of the vanilla vines towards lime mixed up with. 
