BULLETIN 372, U. S. DEPARTMENT OF AGRICULTURE. 
CULTIVATION AND FERTILIZERS. 
The plants should be set in the field in rows 3 feet apart and about 
18 inches to 2 feet apart in the row. This will permit the use of horse 
cultivation as soon as the plants have become established in the field. 
The usual cultivation should be given until the plants are large 
enough to shade the ground and thus prevent the growth of weeds 
which might injure the crop at harvest time. 
In 1912 a series of fertilizer experiments was carried out on 36 
plats. It was found that although certain special methods of treat- 
ment had a marked effect on the percentage of yield of oil and of 
thymol in the oil, the greatest yield, was obtained by promoting the 
growth of the plant and thus securing the largest possible yield of 
herb per acre. 
Acid phosphate gave more herb and a higher percentage of oil 
than did bone black, and calculated on the yield of thymol per acre 
the ratio. was as 2 to 1 in favor of the acid phosphate. Nitrate of 
soda did not give as satisfactory results as sulphate of ammonia. 
The use of an organic source of nitrogen in the complete formula did 
not give as good results as when all the nitrogen was applied in the 
form of sulphate of ammonia. There was a slight difference in favor 
of the application of the potash in the form of sulphate. The best 
results were obtained by the use of a complete fertilizer having the 
following analysis: Nitrogen, 4 per cent; phosphoric acid, 6 per cent; 
potash, 10 per cent. With this fertilizer made from sulphate of 
ammonia, acid phosphate, and sulphate of potash, 600 pounds per 
acre should be sufficient to produce a good crop, and less could be 
used on land having a fair degree of fertility. 
It has been found advisable to make the application of fertilizer 
after the plants have become established in the field, but care should 
be taken to prevent injury to the leaves by the fertilizer. 
The average composition of a number of samples of horsemint 
made both before and alter distillation is shown in Table I, the results 
being calculated on the basis of dry material. 
Table I. — Composition of horsemint before arid after distillation. 
Time of analysis. Ash. 
1 
Nitrogen, 
as am- 
monia. 
Phos- 
phoric 
acid, as 
P 2 5 . 
Potash, 
as K 2 0. 
Per cent. 
Before distillation : 7. 73 
After distillation 8. 17 
Per cent. 
1.46 
1.33 
Per cent. 
0.58 
.54 
Per cent. 
2.38 
2.12 
Taking as a basis the average composition of the herb before 
distillation and allowing 25 per cent as the average quantity of dry 
matter, the quantity found in a large number of determinations, it 
