Red Giant
Also known as: Japanese Mustard · Red Giant Mustard Greens
What's special about Red Giant
Huge Japanese heirloom — 18 in purple-red leaves with green midribs. Bold horseradish-mustard bite; stunning in the garden.
Growing this variety
Red Giant follows the same growing basics as Mustard Greens. Variety-specific maturity above; everything else below applies to the whole Mustard Greens family.
Germination
Spacing & depth
How to plant
Direct-sow into cool moist soil. Bolts fast once days are long and warm, so treat spring sowings as baby leaf and save full-size heads for fall. Cut outer leaves or shear the whole plant; young leaves are salad-mild, mature leaves want a cook.
Grower's tip
Cold turns down the heat and turns up the sweet — fall mustard after two frosts is a different vegetable than the same plant in June. Wasabi-type leaves give real horseradish burn straight from the garden.
Soil preferences
Rich, moisture-retentive loam.
6.0–7.0
Compost + a light nitrogen source (blood meal, aged manure) — greens are all leaf, so they want nitrogen.
Watering
Consistent — 1 in per week minimum, more in heat. Uneven water triggers bolt.
Overhead is fine in the morning; drip is best in humid climates.
Overwatered: soft rot at the crown, yellow lower leaves. Underwatered: bitter flavor, tough leaves, premature bolting.
Prefers top-watering — Top-water at the base in the morning. Overhead water batters open flowers and spreads botrytis on tightly-packed blooms.
Temperature tolerance
55–75°F (13–24°C) — most greens bolt above 80°F (27°C)
45–60°F (7–16°C)
Light frost tolerated by most; kale, spinach, mâche, and collards are cold-hardy and often sweeter after frost.
Container growing
Yes — great in containers
6–8 in deep, any width; a window box works
Perfect for pots and hydroponics; cut-and-come-again mixes give weeks of harvest per sowing.
Succession planting
Every 2 weeks spring and fall. Skip the hottest weeks or use shade cloth.
Detailed harvesting
Cut outer leaves and let the crown keep producing (cut-and-come-again), or cut the whole rosette 1 in above the crown for a fresh flush.
Post-harvest storage & preservation
Rinse, spin dry, and store in a sealed bag with a paper towel in the crisper 5–7 days. Blanch and freeze for cooking greens.
Culinary, medicinal & other uses
Salads, sautés, smoothies, soups. Bitter or overgrown leaves are best cooked, not raw.
Medicinal or traditional uses are shared for interest only — this is not medical advice. Consult a qualified professional before using any plant medicinally.
Seed saving
Lettuce is self-pollinating; spinach is wind-pollinated; brassica greens (kale, arugula, mustard) are insect-pollinated and cross freely.
Lettuce 20 ft; spinach 1/2 mile; brassicas 1/4 mile or cage.
Let a robust plant bolt; harvest dry seed stalks; rub clean; store dry.
Your zone's planting calendar
Pick your USDA hardiness zone and we'll estimate the key dates for mustard greens in your area. These are regional averages — always check your own last-frost forecast before sowing.
My Red Giant Mustard Greens notes
Red Giant Mustard Greens seeds on hand
Track packets and loose seeds you already have. Private to your account.
Par level — leave at 0 for no alert. Anything below par shows on Seed Starting and your shopping list.
From your kitchen — grow mustard greens from what you already have
Let one plant bolt (send up its flower stalk) and it will make hundreds to thousands of seeds. Bolted greens are bitter to eat but perfect for saving.
- 1Pick your best, slowest-to-bolt plant as the seed parent.
- 2Let the flower stalk rise, bloom, and dry brown on the plant.
- 3Cut the whole stalk into a paper bag before it shatters.
- 4Rub between your hands to release seed; sieve out chaff; store dry.
Storage: 3–5 years dry.
Order more seeds
Running low? Reorder from one of these seed stores.
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Other Mustard Greens varieties
Southern Giant Curled
50 daysThe Southern staple — big bright-green frilled leaves, mild-to-hot depending on weather. Slow to bolt and cold-hardy.
Garnet Giant
45 daysFaster and darker than Red Giant — deep burgundy leaves with excellent uniformity. Hybrid vigor, great baby-leaf color.
Wasabi
45 daysSelected for pungency — bright green rounded leaves with a genuine wasabi/horseradish burn. Use young; heat intensifies with age.
Green Wave
45 daysBright green frilly leaves with a strong mustard bite. Slow to bolt, cold-hardy, and excellent for baby leaf or bunching.