The Complete Guide to Starting Lemongrass Seeds Indoors

Lemongrass is a tropical grass that is easy to grow at home from seed Its citrusy, ginger-like flavor makes it a must for Thai and other Southeast Asian cuisine The fragrant leaves can also be made into a refreshing tea. Lemongrass grows quickly into a large, ornamental clump that can be overwintered indoors in colder climates.

Starting lemongrass seeds indoors allows you to better control moisture, temperature, and light exposure during germination It also gives plants a head start on the growing season so you can transplant larger, more robust seedlings outdoors Follow this step-by-step guide for successfully starting lemongrass seeds indoors.

When to Start Lemongrass Seeds

Lemongrass seed starting times depend partly on your growing zone. Since lemongrass thrives in summer heat, you want transplants to be ready to go outside once temperatures have warmed up and the threat of frost has passed.

For Zones 3-7

• Start seeds indoors 12-14 weeks before your last spring frost date.

For Zones 8-11

• Start seeds indoors 8-10 weeks before your last spring frost date.

• You can also direct sow seeds outdoors 3-4 weeks before your last frost.

Check your local frost dates and count backwards from your transplant date to determine your ideal seed starting time.

Gather Supplies for Starting Seeds Indoors

You don’t need fancy supplies to start lemongrass seeds, but having the right materials will help ensure success. Here’s what you’ll need:

• Lemongrass seeds – Look for non-GMO heirloom seeds from a reputable source.

• Containers – Use cell packs, flats, peat pots, or other small containers with drainage holes.

• Seed starting mix – A loose, lightweight mix is ideal. You can make your own.

• Tray or dome – Covers create a greenhouse environment for seeds.

• Grow lights – Lemongrass needs 14+ hours of light per day.

• Bottom heat – Helps maintain warm soil temperatures.

• Heat mat – Place under trays to provide 70-80°F soil warmth.

• Thermometer – Monitors soil temperature under domes.

• Spray bottle – For gently misting soil. Avoid overwatering.

• Labels – Identify seed varieties as they sprout.

How to Plant Lemongrass Seeds

Follow these simple steps for planting lemongrass seeds:

1. Fill containers with moistened seed starting mix. Gently firm it down.

2. Sow seeds 1/16 inch deep and 1 inch apart. Lemongrass needs light to germinate.

3. Mist soil, cover trays, place on heat mats set to 70-80°F.

4. Once sprouted, move to full spectrum grow lights, 14-16 hours per day.

5. Keep soil moist but not soaked. Allow it to dry out slightly between waterings.

6. Remove domes once seedlings appear. Prioritize air circulation.

7. Thin seedlings to one plant per cell once the second set of leaves appear.

8. Harden off plants before transplanting outside in 4-6 weeks.

Caring for Lemongrass Seedlings

Proper care once seeds sprout is key:

• Maintain warm soil temperatures around 70°F until sprouted.

• Keep seedlings under grow lights 14-16 hours per day. Supplement natural light.

• Allow the top inch of soil to dry out between waterings. Don’t oversaturate.

• Ensure good air circulation once domes are removed.

• Feed with a balanced liquid fertilizer once a week.

• Support tall, leggy seedlings with plant stakes if needed.

• Gradually expose seedlings to outdoor conditions over 7-10 days before transplanting.

Transplanting Lemongrass Outdoors

• Harden off seedlings for 7-10 days before transplanting. Slowly introduce to sun, wind, and temps.

• Transplant after all chance of frost has passed, when soil reaches 65°F.

• Space plants 12-24 inches apart in full sun. They will reach 2-4 feet wide when mature.

• Select a site with well-draining soil. Amend with compost if needed.

• Water transplants daily for the first week, then allow soil to dry out between waterings.

• Apply an organic vegetable fertilizer monthly during the growing season.

• Mulch around plants to retain moisture and reduce weeds.

Ongoing Care of Lemongrass

A few simple practices keep lemongrass looking its best:

• Water whenever the top 1-2 inches of soil become dry. Avoid overwatering.

• Fertilize monthly with a balanced organic fertilizer.

• Remove any dead leaves and spent stalks.

• Harvest stalks when they reach 1/2 inch diameter.

• Before frost, prune stalks to 6 inches. Dig up roots and overwinter indoors.

• In zones 9-11, mulch plants in fall for extra frost protection.

• Start this year’s seeds 8-12 weeks before last frost to replace overwintered plants.

Tips for Growing Lemongrass Successfully

Follow these tips and tricks for getting the most out of your lemongrass plants:

• Start more seeds than you need in case of problems. Germination rates vary.

• Don’t let seeds dry out during germination. They need constant moisture.

• Warm soil temperatures are critical – use a heat mat for best results.

• Once sprouted, prioritize air circulation. Remove domes promptly.

• Pinch off top growth to encourage bushier, fuller plants.

• Harvest stalks when they are 1/2 inch wide at the base for best flavor.

• In cold climates, overwinter plants indoors in pots near a sunny window.

• Mist leaves regularly to boost humidity. Lemongrass prefers 40-60% humidity.

• Divide overcrowded clumps in spring to rejuvenate plants and create new ones.

Troubleshooting Common Problems

• Poor germination – Ensure warm enough soil temps, keep seeds moist.

• Leggy seedlings – Not enough light, use grow lights for 14+ hours per day.

• Yellow leaves – Overwatering, allow soil to dry between waterings.

• Few stalks – Needs more sun, fertilizer. Pinch off tops to encourage new growth.

• Stunted plants – Could indicate poor drainage or root competition. Transplant.

• Pests – Treat aphids with insecticidal soap, slugs with diatomaceous earth.

Harvesting and Using Lemongrass

• Harvest stalks when they reach 1/2 inch diameter at the base.

• Use sharp scissors or a knife to cut stalks off at ground level.

• Remove tough outer leaves before use. The white inner core is more tender.

• Adds amazing flavor to Thai curries, soups, teas, and more.

• Dries well for teas. Can also be frozen for later use in recipes.

• Entire stalks or chopped pieces can be used. Discard before serving.

The Reward of Growing Lemongrass

Now that you know when and how to start lemongrass seeds indoors, you can look forward to months of enjoying this ornamental, edible grass. Its exotic flavor and fragrance simply can’t be duplicated. Homegrown lemongrass is fresh and costs just pennies compared to store prices. Plus you can harvest it anytime you need it for your favorite recipes. Get your seeds started now for the best lemongrass yet this summer!