Red Shiso Seeds - Aka Shiso - Perilla frutescens var crispa

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

USDA Zones 3-11: Grows as a warm-season annual across all zones. Shiso is not frost-tolerant and must be planted outdoors after all danger of frost has passed and the soil is very warm.

Best Performance (Zones 5-9): Thrives in areas with long, hot, and sunny summers. These zones provide the 60-80+ frost-free days needed for it to grow into a large, bushy, and productive plant.

Northern Zones (3-5): Starting seeds indoors is highly recommended to get a head start. Start 4-6 weeks before your last frost date. Transplant outdoors only when the weather is settled and nighttime temperatures are above 50 degrees F.

Hot Climate Zones (9-11): Shiso loves heat and performs exceptionally well. Plant in early spring after the last frost for a long summer harvest. In the most intense desert heat (100+ degrees F), plants will perform best with partial afternoon shade and consistent watering.

Soil Temperature: Requires warm soil for germination, ideally between 65-70 degrees F. Germination is notoriously slow and erratic, so be patient. Seeds will fail in cool, damp soil.

Growing Season: Requires 60-80 frost-free days to produce a harvestable, bushy plant. It will grow productively until the first frost in fall.

Learn more about USDA Hardiness Zones here

When to Plant (Indoors):

Recommended Method: Start seeds indoors 4-6 weeks before your average last frost date.

Pro-Tip: For better germination, you can cold-stratify the seeds. Mix seeds with a small amount of damp sand or a moist paper towel, place in a plastic bag, and refrigerate for 1-2 weeks before planting.

When to Plant (Outdoors):

Direct sow after all danger of frost has passed and the soil has warmed to at least 65 degrees F.

Where to Plant:

Sunlight: Full sun is needed for the best, deepest red-purple leaf color. It will tolerate partial shade, but the leaves may be greener.

Soil: Plant in rich, moist, but well-drained soil. Amend your planting bed with aged compost.

How to Plant (Seed Starting):

Depth (Critical): Seeds need light to germinate. Do NOT cover the seeds with soil.

Process: Press the tiny seeds (stratified or not) firmly onto the surface of a sterile, moist seed-starting mix.

Germination: Be patient. This is the hardest part. Germination is slow and erratic, often taking 7-21 days. Keep the soil surface consistently moist (use a spray bottle) and warm (65-70 degrees F).

How to Plant (Transplanting):

Harden Off: Acclimate your indoor-sown seedlings to outdoor conditions for 7-10 days.

Spacing: Space plants 12 inches apart to give them room to become bushy.

Growing and Care:

Pinching: When plants are 6-8 inches tall, pinch the central top stem (just like basil). This forces the plant to branch out from the base, resulting in a much bushier, more productive plant.

Watering: Shiso is thirsty, especially in full sun and heat. Keep the soil consistently moist, but not waterlogged.

Fertilizing: Feed with a balanced liquid fertilizer every 4-6 weeks, or side-dress with compost.

Controlling Spread: This is essential. Shiso is a prolific self-seeder. To prevent it from taking over your garden, cut off the flower spikes in late summer/early fall before they mature and drop seeds.

Harvesting:

When: You can begin harvesting leaves once the plant is 8-10 inches tall.

How: Harvest by pinching or snipping stems just above a set of leaves. This will encourage even more branching.

Use: Harvest leaves as needed for cooking, pickling, or teas. The leaves, buds, and flowers are all edible.