Parsley (Petroselinum sativum) is a biennial herb grown everywhere in gardens for use in garnishing and seasoning. All parts of the plant contain a volatile oil, that from the seed being especially rich in a constituent known as apiol, or "parsley camphor," which is still used to some extent in medicine. In the crude-drug trade there is a small demand for the root, leaves, and seed.
A rich and rather moist soil is desirable for the growing of parsley. The seeds germinate slowly and are frequently sown early in the spring in cold frames or seed beds, from which the young plants may be removed later and set in the open in rows 12 or more inches apart and about 6 inches apart in the row. When the leaves are fully grown they may be collected and dried in the usual manner. The plants flower in the second year, and as soon as the seed is ripe it is harvested and carefully dried. At the end of the second growing season, late in October, the root may be dug and should be well washed and carefully dried. Artificial heat may be used in drying if necessary.
On small areas yields of seed at the rate of about 185 pounds per acre have been obtained. During the past few years the wholesale price of the seed has varied from 10 to 70 cents a pound, according to demand and season. From 15 to 50 pounds of seed are required to yield 1 pound of the oil, which in June, 1920, was quoted at $6.50 to $7 a pound.
[PENNYROYAL.]
Pennyroyal (Hedeoma pulegioides) is an annual plant, flowering from June to October, and is found in dry soils from Nova Scotia and Quebec to Dakota and southward. Both the dry herb and the oil obtained therefrom by steam distillation form marketable products.
Pennyroyal grows well on average upland soils and is frequently abundant on sandy or gravelly slopes. In field planting the seeds should be sown in rows in the fall and covered not to exceed one-quarter of an inch, since they rarely germinate if planted at a greater depth. The plants come up early in the spring, and to secure the best results clean cultivation and freedom from weeds are essential, as with all cultivated crops.
Early in the summer, when the plants are in full flower, they may be mowed. To prepare the herb for market the plants are dried, preferably in the shade, and carefully packed immediately after drying. All the large stems should be removed in order to improve the quality of the product. The herb should be marketed promptly, since it deteriorates with age. For the production of the volatile oil, the plants should be harvested when in full flower and distilled without drying.
Returns from experimental areas indicate that a yield of about 1,200 pounds of dry herb per acre may be expected. The yield of oil varies from 15 to 30 pounds per acre. The price paid for the dry herb usually ranges from 1 to 2 cents a pound. The wholesale price of the oil ranges from about $1 to $2 a pound.