Parsley

Soak the seed, then sow parsley early

Soak seed in warm water for up to 24 hours before sowing. Start indoors six to eight weeks before your last frost, or direct sow once the soil has warmed and frost danger has passed, keeping the surface damp the whole time. Expect two to five weeks before anything comes up, so do not give the row up for dead and reseed over it. Parsley germinates erratically and slowly even under ideal conditions, and a long soak helps leach the seed coat. Most parsley failures are impatience, not bad seed.

Feed parsley once or twice through the season

Work in a 5-10-5 fertilizer at about three ounces per ten feet of row, once or twice over the growing season. For parsley in outdoor containers, use a liquid feed at half strength every three to four weeks; indoors, stretch that to every four to six weeks. Parsley is cut repeatedly, and every harvest carries off leaf nitrogen the plant has to rebuild before it can push the next flush of outer stems.

Thin parsley seedlings to a hand's width apart

When seedlings are two to three inches tall, thin leaf parsley to a final spacing of ten to twelve inches. If you are growing a root type like Hamburg for the taproot, thin to three to five inches instead (Arkansas Cooperative Extension), which is tighter than you would space it for leaves. Crowded parsley shades itself into thin, soft growth and holds leaf wetness long enough for leaf spot to take. Root types are thinned tighter on purpose because spacing drives root size and shape rather than leaf yield.

Septoria leaf spot: water low and rotate the ground

Look for small sunken angular tan to brown spots with red-brown margins, later going gray in the center with tiny black specks in them. Pick off and bin spotted leaves as you see them, water at the base with drip or a wand instead of overhead, and do not work through the planting while the foliage is wet. Move parsley and its carrot-family relatives to fresh ground for two to three years, or four if the spot was bad. Septoria petroselini arrives on infested seed and then spreads by splash, so every rain or sprinkler cycle carries it to new leaves. Its spores stay infectious on dead, dried parsley debris for several years, which is why last year's bed reinfects this year's crop.

Leave the striped caterpillars alone

If you find fat green caterpillars banded with black and yellow eating your parsley, leave them be. They are black swallowtail larvae, and parsley is one of their few host plants. Extension notes they are seldom numerous enough to cause much damage; if a plant is truly being stripped, handpick them onto another parsley or carrot-family plant rather than spraying. Aphids also show up but are usually cleaned up by natural predators and parasites, and a hose-off handles the rest. Black swallowtails can only lay on carrot-family plants, so your parsley patch is a butterfly nursery whether or not you meant it to be. A few chewed stems is the whole cost, and an insecticide here kills the larvae along with the predators that were already handling your aphids.

⚠ No insecticide is warranted on parsley for caterpillars. Handpick or relocate instead — the damage is cosmetic and the spray costs you the butterflies and the aphid predators both.

Overwinter one plant for flowers and seed

Let one or two plants ride through winter instead of pulling them, mulching them in cold zones to improve their odds; flat-leaved types come through winter better than curly ones. Sow fresh parsley for eating next spring regardless. The overwintered plants will send up greenish-yellow flower umbels in compound clusters their second year, followed by small ridged seed you can collect. Parsley is a biennial: it only flowers in its second year, and once it bolts the leaves go tough and bitter, which is why it is normally restarted annually. Sacrificing a plant to the second year is how you get the umbel bloom, the self-sown seed, and a swallowtail nectar and egg-laying stop, without giving up your kitchen supply.

Cut the outer stalks at the ground, not the top

Snip whole stalks off close to the ground, always starting with the outermost ones and working in. Never shear the top of the plant. Keep cutting right through fall and light frosts, until the plant flowers. If you are growing a root type, go easy on the tops — the leaves are what fill the root. Parsley grows from a central crown, so the newest leaves are in the middle. Taking the outer stalks leaves that growing point intact and the plant simply keeps producing, while cutting across the top removes the young leaves and stalls it.