Mustard greens

Brassica juncea · Cabbage family (Brassicaceae)

At a glance
Hardiness zones	2 to 11
Sun	full sun to part shade
Water	moderate
Life cycle	annual
Frost	Half-hardy: takes a light frost
Soil pH	6.0–6.5
Spacing	6 to 12 inches
Days to harvest	25 to 50 days

About Mustard greens

Mustard greens are fast-growing, peppery leaves. They are easy to grow in spring or fall and can be picked as baby salad leaves or full-size cooking greens.

Grown as a cool-season annual in every zone; time it for the cool weather of spring or fall. Plants take frost but may be damaged by a hard freeze, and summer heat makes them bolt.

When to plant

Timing is counted from your average last spring frost (and first fall frost). Sow & Tell works out the actual dates for your ZIP code.

Sow seeds outdoors: 1 to 6 weeks after the last frost
Fall planting: 10 to 16 weeks before the first fall frost

Days count from seeding and depend on the variety and whether you pick baby or full-size leaves. Sow again every 2 to 3 weeks to stretch the harvest; spring sowings may bolt as it warms.

Soil

Moist, well-drained soil rich in organic matter; keep it evenly watered.

Follow a soil test and keep pH 6.0 to 6.5; without a test, work in about 2 to 3 lb of complete garden fertilizer such as 10-20-10 per 100 sq ft (or 1 cup per 10 ft of row).

Feeding

when plants are 4 to 5 inches tall: complete garden fertilizer such as 10-20-10. Spread about 1/2 cup per 10 ft of row beside the plants, mix it lightly into the soil and water it in; add more later on sandy soil in a wet season.
after cutting a harvest, to push new leaves: nitrogen fertilizer such as 21-0-0. Give a light side-dressing beside the row and water it in.

Plants need enough nitrogen for dark green leaves, but greens turn tough and go to seed fast once days get long and hot, so plant for cool weather.

Harvest

Pick leaves at baby size for salads, or when full-sized and still tender for cooking.

Remove the outermost leaves and let the center keep growing, which stretches the harvest; a light nitrogen side-dressing after picking helps new leaves form. Leaves can be picked at baby size (about 25 days) or full size.

Varieties (13)

Extension sources document 13 mustard green varieties; several salad types (Ruby Streaks, Golden Streaks, Red Streaks) are listed by name only.

Variety	Type	Days	Notes
Florida Broadleaf	Broad leaf	40 to 50 days	Broad, flat leaves with sawtooth edges.
Green Wave	Curled leaf	21 to 45 days	Very curly leaves.
Southern Giant Curled	Curled leaf, heirloom	50 to 70 days	Large plants with very curly leaves.
Savannah	Hybrid, broad leaf	35 days	Thick, very dark green leaves with fewer yellow leaves as it ages. Slower to bolt than open-pollinated types and good for home gardens.
Osaka Purple	Purple leaf, heirloom	40 days	A purple-leaved heirloom mustard.
Garnet Giant	Red leaf	45 days	Red leaves that turn green when cooked.
Red Giant	Red leaf, heirloom	45 days	A red-leaved heirloom mustard. UF/IFAS lists it as Giant Red.
Golden Streaks	Salad type		A salad mustard on Kansas State's list.
Red Streaks	Salad type		A salad mustard on Kansas State's list.
Ruby Streaks	Salad type		On Wisconsin Extension's list.
Large Smooth Leaf	Smooth leaf	49 days	On the Texas list.
Tendergreen	Smooth leaf, heirloom	35 to 40 days	A smooth-leaved heirloom.
Golden Frills		21 to 45 days	On Kentucky's and Wisconsin's lists.

Good neighbors

Cabbage, Broccoli, Kale, Cauliflower, Brussels sprouts, Collards, Kohlrabi

UMN Extension says mustard can serve as a trap crop that lures flea beetles away from other cabbage-family crops, working best in a mix of several trap species; expect the mustard itself to get chewed.

Pests to watch for

Flea beetles, Aphids, Bagrada bug

Diseases and problems

Cercospora leaf spot, Black rot of cabbage-family crops, Nitrogen deficiency, Alternaria leaf spot (cabbage family), Clubroot, White rust, Turnip mosaic

In the kitchen

Cooked like collards or turnip greens, stir-fried, or used raw as a spicy baby green.

Keeping it: Wrap unwashed leaves in damp paper towels inside a plastic bag in the crisper and use them within about 3 to 5 days; the flavor gets stronger the longer they sit.

Pets: The ASPCA lists its 'White/Black/Yellow Indian Mustard' entry (Brassica species) as toxic to horses: isothiocyanates can cause stomach irritation and colic. It is not listed as toxic to dogs or cats.

Sources

Photo: Photo: thebittenword.com, CC BY 2.0, via Wikimedia Commons (CC BY 2.0). Photo resized for the web.

Planting dates and advice are general guidance; check with your local Cooperative Extension office for your area.