How Much Water Does a Parsley Plant Need?

Parsley (​Petroselinum​ ​crispum​) is an often-used biennial herb, not only as an attractive garnish, but also to add flavor and color to a variety of dishes, including soups, sauces, stew, casseroles and salads. You'll find three varieties of the plant in seed catalogs: Curly parsley, flat-leaf or Italian parsley, and a relatively uncommon variety that's grown for its large, parsnip-like root. With adequate water and sunlight, parsley thrives in your herb garden or in a container on your patio, balcony or kitchen windowsill.

Water in-ground parsley deeply once every week, providing enough water to moisten the plant's root system, then allow the soil to dry slightly. Parsley favors light soils with plenty of drainage, so it may require irrigation twice weekly during periods of hot, dry weather to keep the soil from becoming completely dry.

A 2- to 3-inch layer of mulch such as dry grass clippings or chopped pine bark keeps the soil moist and conserves water. As an added benefit, mulch enriches the soil and helps keep weeds in check. If you live in an area where water is scarce and must be conserved, consider using a plastic mulch to suppress weeds and minimize evaporation from the soil. A simple soaker hose underneath your mulch, whichever type of mulch you choose to use, is an excellent option for efficient irrigation.

When grown outdoors container parsley should be checked often, as potted parsley located outdoors dries much faster than parsley grown indoors. Water container parsley whenever the top of the soil feels dry to the touch, especially if it's in direct sunlight throughout the heat of the day. Unlike many herbs parsley may benefit from partial shade.

Indoors, container parsley is watered deeply but less frequently. Water parsley deeply whenever the top of the soil feels dry, then let the excess water run through the drainage hole. Never allow the container to stand in water, as doing so may cause the plant to rot. Allow the soil to dry slightly before you water again, but don't let the soil become bone dry.

Plant parsley in a well-drained garden spot, as parsley may rot in soil that is continually damp. Parsley grows in most types of well-drained soil, but benefits from soil amended with compost or manure. Plant container parsley in a container filled with a good quality peat- or compost-based potting mixture. Always use a container with bottom drainage.

Fertilize in-ground parsley every six to eight weeks, using a balanced, dry fertilizer applied according to the directions on the package label, based on soil-test recommendations. Container parsley requires more frequent feeding, especially when the plant is grown indoors.

Using a liquid or water-soluble fertilizer, fertilize indoor parsley every three to four weeks. Feed container parsley located outdoors every four to six weeks. For container parsley, dilute the liquid or water-soluble fertilizer to half the strength recommended on the label. Always water parsley immediately after planting, as applying fertilizer to dry soil may scorch the roots.