Parsley is a biennial herb, whose roots and leaves are used in cooking. In their first year of growth, parsley plants produce the leaves that are used in cooking, both as an herb and as an attractive garnish. In their second year, these plants go to seed very fast. Many parsley growers prefer to start a fresh crop every year, because of this reason. To propagate parsley, you can either harvest your own seeds, or buy seeds or seedlings from the local greenhouse.
If you have mature parsley plants in your backyard or home, retain only the healthiest ones for harvesting seeds. This will ensure that the plants you grow from these seeds will retain all the healthy characteristics. Parsley plants can be over-wintered to their second year of life, when they will bloom and produce seeds. Seeds are ready to be harvested when they are dark brown in color. To harvest the seeds, cut the parsley bloom and scatter the seeds onto a fine white cloth. Dry the seeds for about 2 weeks before storing or sowing them.
The trickiest aspect of parsley propagation is getting the seeds to germinate. Parsley seeds require a warm, moist environment to germinate. You can sow the parsley seeds indoors any time of the year, if you plan to grow your plants in a container indoors. However, if you want to grow parsley in your backyard, you must sow the seeds indoors a few weeks before the last frost.
Sow the parsley seeds about a quarter of an inch deep in a soilless potting mix that is composed of peat moss. Use a seed tray for this purpose. The temperature must be at least 21ºC. You can do a few things to hasten germination of the parsley seeds. One method is to soak the seeds in warm water for a day before sowing. Another useful trick is to sow the seeds in the potting mix, and then pour very hot water over them. This will break the seed dormancy. If you sow more seeds, you have a higher chance of getting more plants. You can then discard the unhealthy seedlings, and thin the remaining ones to a distance of about 6 inches from each other.
When the parsley seedlings are 3 to 4 inches tall, transplant them to the outdoors or to a container. If you are using a container, make sure it is deep enough to accommodate the deep tap root of your parsley plant. A depth of a foot is usually sufficient. Plant a single seedling in each container.
If planting in the soil, prepare the planting spot well in advance, by incorporating sufficient amount of organic matter. Make sure the soil is not alkaline. You can add sulfur pellets to the soil to increase acidity. Plant the seedlings at a distance of 1 foot from each other. Mulch the plant with leaf mold or bark dust, without covering the roots. Cover the seedlings for a week, till they are accustomed to their new location. Water the plant regularly, and supply a general liquid fertilizer 3 to 4 times a month.