The yield that can be obtained from drug plants in different localities
will naturally vary according to the suitability of the situation for
the plants selected for cultivation. Even in the same locality wide
variations in yield will result from differences in the lay of the land
and in soil, drainage, and seasonal conditions. The skill of the grower
and the degree of care and attention which he bestows upon his crop are
also factors affecting yield.
Many of the drug plants mentioned in this bulletin have not been
grown on a scale large enough to give a very satisfactory basis for
calculating yields. Acreage yields calculated from the product of small
garden plats are generally untrustworthy, since in such plats the
plants are usually more favorably situated with respect to soil and are
given better culture than when under field conditions. Moreover, as the
area increases, it becomes more difficult to maintain an approximately
perfect stand and to protect the crop from the ravages of insects or
other destructive agencies. The returns from small experimental areas
can at most be regarded as only an indication of the yield that may be
expected under favorable conditions, and the prospective grower will
do well to proceed cautiously until he has determined for himself the
possibilities of yield in his particular location.