Parsley is a semi-hardy vegetable that grows well in cool to warm conditions. Technically, it is a biennial (the full span from seed to flower is 2 years), but it will not survive freezing winter temperatures, so it is usually treated as an annual.
Start seeds indoors 12 weeks before the frost date, or purchase transplants. Parsley takes a long time to germinate (2-4 weeks), so buying transplants is recommended.
Harden off and transplant outside 5 weeks before the frost date.
If you live in a mild climate with a late or no fall frost date (after Nov 1), you might be able to grow parsley until it flowers and goes to seed.
Soil and Fertilizer
Parsley grows best in a rich soil; amend with lots of compost and fertilizer (chemical or organic) at planting and up to every 4 weeks.
Fertilizer: 16-16-8 at planting; 10-10-10 repeat up to every 4 weeks.
Harvest by cutting the outside stalks of parsley as soon as the plants develop sprigs with 3 leaves. Harvesting this way promotes new growth of the plant.