• Variety: Thai Basil
• Family: Lamiaceae
• Scientific Name: Ocimum basilicum var. thyrsiflora
• Seeds per Gram: ~650–700
• Origin: New Zealand
• Germination Rate: ~91%
• Germination Time: 2–4 days
• Harvest Time: 18–30 days (microgreens); 60–90 days (full plants)
• Colour: Slender green leaves; compact habit as microgreens
• Flavour: Aromatic basil with a fresh anise/licorice note
• Nutrients: Vitamins K, E, C; calcium; iron; beta-carotenes
• Status: Non-GMO, untreated, open-pollinated
• Uses: Microgreens, culinary herbs, garnishes, full maturity

Preparation: Use a 20 cm × 20 cm tray with drainage. Fill with 3–4 cm of seed-raising mix, coir, or a fine soil blend. Thai basil is mucilaginous (forms a natural gel when wet) — do not pre-soak.

Sowing: Broadcast 2–3 g of seed per 20 cm × 20 cm tray for a dense, even canopy. Press seeds gently to ensure contact (don’t bury). Mist lightly and cover with a humidity dome or tray.

Germination: Keep covered 2–5 days at 20–25 °C. Maintain consistently moist (not soggy) conditions; the gel coat needs humidity to anchor seedlings. Germination typically begins in 2–4 days.

Light: Uncover once most seeds have sprouted. Provide bright, indirect light or LED grow lights to prevent legginess and build strong flavour.

Watering: Bottom-water or fine-mist as needed to keep media evenly moist. Avoid waterlogging to reduce damping-off risk.

Growth: Thai basil grows slower than fast microgreens. Expect sturdy, fragrant shoots ready in 18–30 days; for full plants, grow on 60–90 days.

Harvesting: Snip at 5–7 cm tall with clean scissors, just above the media, once cotyledons and first true leaves have opened.

Storage: Best used fresh. Store harvested microgreens in a sealed container in the fridge for up to 5 days.

Troubleshooting: If seedlings look leggy or pale, increase light intensity. For damping-off, improve airflow, avoid overwatering, and keep temperatures stable. If germination is patchy, check humidity under the dome during the first 2–3 days.

Light & Colour

Provide strong indirect light or full-spectrum LEDs to encourage compact growth and rich, vibrant colours. The deepest hues are usually achieved only with supplemental lighting.

Temperature

Both excessive cold and excessive heat can affect reliability and consistency in microgreen production. Controlled environments deliver the best results.

Moisture Balance

Keep the growing medium consistently moist but never waterlogged. Overwatering reduces oxygen in the root zone and leads to weak, spindly stems.

Damping Off

A common microgreens issue where seedlings rot and collapse, caused by water moulds thriving in overly wet conditions. To prevent this, avoid overwatering. Once seeds have sprouted, stop misting from above and switch to bottom watering. Always use sterile trays, tools, and fresh growing media for each new crop. In some cases, mould spores may already be present in the water source. Solutions include ozone-treating your water (an organic practice) or using reverse osmosis water. As a last resort (not recommended), a diluted cleaning agent such as chlorine or bleach can be applied with extreme caution.

Reliable Quality Seeds

Strong, healthy microgreens start with top-quality seed. Always buy from trusted suppliers who use proper storage systems such as industrial dehumidifiers, air-conditioning, cold storage, and even carbon dioxide–controlled atmospheres to maintain seed integrity.

Poor handling at the supplier level can lead to seed degradation, lower germination rates, mould issues, or even contamination. In some cases, seeds may be sold as “microgreen” seed without testing or proven history—often substitutes chosen for profit rather than performance. These second-rate seeds can result in weak, inconsistent crops with undesirable traits.

Tip: Store your own seed in a cool, dry, airtight container to preserve reliability for future sowings. Fridge or Freezer: For long-term storage, refrigeration or freezing works well — just let seeds return to room temperature before planting.

Seeds don’t exactly “expire,” but their ability to sprout gradually declines over time. With the right storage, your microgreen seeds will stay viable for years, giving you strong germination and healthy trays every time.

Key Storage Tips

• ✅ Cool, Dry & Dark: Store seeds away from heat, light, and humidity for maximum lifespan.
• ✅ Airtight Containers: Use sealed jars or pouches; add a silica gel packet to guard against moisture.
• ✅ Fridge or Freezer: For long-term storage, refrigeration or freezing works well — just let seeds return to room temperature before planting.

Microgreen Seed Viability Guide

Here’s how long you can expect popular microgreen seed varieties to last under proper storage:

• 1–2 Years: Garlic Chives, Onion, Corn Salad
• 3–4 Years: Radish, Sorrel, Basil
• 4–5 Years: Beets, Broccoli, Cabbage, Mustard, Kale, Mizuna

Quick Germination Test

Not sure about older seeds? Test them first:

1. Place 10 seeds (e.g., broccoli, pea, or sunflower) on a damp paper towel inside a sealed bag.
2. Keep moist at room temperature.
3. Check after 5–10 days to see how many sprouted — that’s your approximate germination rate.