Thai Basil Seeds - Siam Queen - Ocimum basilicum

2, 3, 4, 5, 6, 7, 8, 9, 10, 11

USDA Zones 2-11 - Grows as a warm-season annual in all zones. Basil is extremely sensitive to cold and will die with the first frost.

Best performance in Zones 4-11 where long, warm summers provide ideal growing conditions.

Northern zones (2-5) - Start seeds indoors 4-6 weeks before the last expected frost date. Plant outdoors after all danger of frost has passed and the soil has thoroughly warmed. Can be grown in a sunny window or under grow lights indoors for year-round harvest.

Hot climate zones (9-11) - Plant in early spring for summer harvest. In desert regions with extreme heat, some afternoon shade can prevent wilting and stress. Plant again in late summer for a fall harvest.

Soil temperature critical - Requires warm soil for germination. Sow seeds after the soil has warmed to at least 70F, with optimal soil temperature of 75-85F.

Growing season needs - Requires 60-90 frost-free days for full production potential, making it suitable for all zones when planted at the appropriate time relative to local frost dates.

Learn more about USDA Hardiness Zones here

When to Plant:
Start seeds indoors 4-6 weeks before your last expected frost date. Do not transplant outdoors until all danger of frost has passed and night temperatures are consistently above 50F. You can also direct sow seeds outdoors after the soil has warmed to at least 70F.

Location and Soil:
Choose a location that receives full sun (at least 6-8 hours of direct sunlight per day). In very hot climates, partial afternoon shade can be beneficial. Thai basil thrives in rich, well-draining soil with a good amount of organic matter. A soil pH between 6.0 and 7.0 is ideal.

Starting Seeds:

Fill seed starting trays or pots with a high-quality, sterile seed starting mix.

Sow seeds about 1/4 inch deep.

Lightly cover the seeds with soil and gently water to moisten the mix.

Place the trays in a warm, sunny location or on a heat mat.

Keep the soil consistently moist until seedlings emerge, which typically takes 7-14 days.

Once seedlings have their first true leaves, thin to one plant per cell.

Transplanting Outdoors:

Harden off seedlings for 7-10 days before transplanting to acclimate them to outdoor conditions.

Space plants 12-18 inches apart in the garden bed.

Dig a hole slightly larger than the root ball, place the plant in the hole, and backfill with soil.

Water thoroughly after transplanting.

Care and Maintenance:

Watering: Provide consistent moisture, especially during dry periods. Water at the base of the plant to keep the leaves dry and prevent fungal diseases.

Fertilizing: Amend the soil with compost before planting. You can also use a balanced, all-purpose fertilizer every 4-6 weeks, or a fish emulsion fertilizer to encourage vigorous growth.

Pinching/Harvesting: To encourage a bushier plant and prevent the stems from becoming woody, pinch off the top leaves and flower buds regularly. This will also prolong the harvest.

Pests and Diseases: Watch for common pests like aphids and spider mites. Good air circulation is essential to prevent powdery mildew and other fungal issues.