36 
SPICES 
CHAP. 
to cool, it is used for manuring. This burnt earth is 
very suitable for such plants as vanilla and pepper, 
which require much potash. 
A certain quantity of lime is recommended to be 
added to the burnt earth and leaf- mould, especially 
where soils are deficient in this element. 
Animal manure, such as cow-dung, is not recom- 
mended. Orchids of all kinds seem to dislike any 
animal manure, and vanilla is no exception. Should 
farmyard manure be used, it must only be very old 
and well-rotted stuff, and then but little should be used 
mixed with the leaf- mould. Some planters have 
recommended that in cases where the soil is stiff and 
clayey, and deficient in humus, trenches 3 or 4 ft. 
long and 1 or 2 ft. deep should be dug and filled 
with leaf-mould and sand to above the level of the 
ground (to allow for sinking), and the vanillas should 
be planted there. Most planters, however, condemn this 
proceeding, as the holes are liable to become water- 
logged. Vanilla is a surface feeder, the roots spreading 
between the humus and subsoil, so that practically 
the only feeding ground of the plant is the humus 
layer. 
Macfarlane even is inclined to condemn digging or 
ploughing previous to planting, preferring to leave the 
humus layer on the top of the soil unmixed with the 
subsoil. Any rotting vegetable matter, such as the 
leaves and stumps of bananas, coco-nut leaves, grass, etc., 
should be thrown on the surface and allowed to decay 
there. 
The amount of manuring required naturally varies 
with the nature of the subsoil and the depth of the 
humus. In Tahiti, Bourbon, and Mexico, where the 
vanilla is cultivated, the soil is volcanic, and conse- 
quently richer than the stiff alluvial clays so commonly 
met with in many tropical regions. In the latter class 
of soils vegetable manures of the character above men- 
tioned are necessary. 
In the Colonial Eeport of the Seychelles for 1905, 
