For optimal germination rates, initiate seed propagation indoors under controlled conditions—unless the species exhibits a high sensitivity to root disturbance. This approach allows precise regulation of temperature, humidity, and light, improving germination consistency and seedling viability. Do not skip any recommended seed treatments, as they are essential for uniform and successful germination.
Keep soil evenly moist during germination. DO NOT LET IT DRY OUT—once seeds begin absorbing water (imbibition), drying can kill the seed embryo, and even brief dryness after sprouting can kill seedlings.
When to Sow
- Indoors: 30–40 days (4–6 weeks) before your last spring frost.
- Outdoors: Direct sow in early spring once soil is workable, or in late summer for a fall crop.
Germination Conditions
- Optimum Temperature: 15–21 °C (60–70 °F)
- Germination Time: Up to 14 days
- Light Requirement: Darkness or light-covered — sow shallowly.
How to Sow Indoors
- Sow seeds 3–6 mm (⅛–¼ in) deep in trays or small pots filled with fine seed-starting mix.
- Cover lightly with soil or vermiculite.
- Maintain consistent moisture.
Humidity: Use a humidity dome or clear cover to maintain consistent moisture during germination. Open the dome BRIEFLY once per day to allow fresh air in and reduce mold risk. Remove the dome entirely once seedlings emerge.
Post Germination Care
- Transplanting: Harden off seedlings and transplant outdoors once frost risk has passed.
- Spacing: Thin or transplant to 20–30 cm (8–12 in) apart in rows 30–45 cm (12–18 in) apart.
- Plant Type: Annual leafy vegetable.
- Mature Height: 20–40 cm (8–16 in).
- Growing Tips: Prefers well-draining, fertile soil with consistent moisture. Bitter flavor increases if plants are stressed by heat or drought. For a milder taste, blanch heads by tying outer leaves over the crown 1–2 weeks before harvest.
More guides at: bloomoutlet.com/seed-guides