Planting lemongrass at the right time ensures strong root development before summer heat arrives. Knowing when to plant lemongrass is the first step to growing this fragrant, useful herb successfully. If you time it wrong, your plants may struggle or fail entirely.
Lemongrass loves warmth and hates frost. It grows best when soil temperatures are consistently above 60°F (15°C). Plant too early and cold soil will rot the roots. Plant too late and the plant won’t have enough time to establish before winter.
This guide covers everything you need to know about the perfect planting window. You will learn about climate zones, indoor starting, and common mistakes to avoid.
When To Plant Lemongrass
The ideal time to plant lemongrass is in late spring, after the last frost date has passed. For most gardeners, this means planting between April and June. The soil should be warm, not just the air.
Lemongrass is a tropical plant native to warm regions. It cannot survive freezing temperatures. Even a light frost can kill the leaves and damage the roots. That is why waiting until the danger of frost is completely over is critical.
Check your local frost dates using the USDA Hardiness Zone map. In zones 8 and warmer, you can plant earlier. In cooler zones, you may need to wait until late May or even June.
Planting By Climate Zone
Your specific climate determines the best planting window. Here is a breakdown by zone:
- Zones 9-11: Plant in early spring, March to April. You can also plant in fall for a winter harvest.
- Zones 7-8: Plant in mid-to-late spring, April to May. Soil warms up slower here.
- Zones 5-6: Plant in late spring, May to early June. Start seeds indoors 6-8 weeks before last frost.
- Zone 4 and colder: Only grow as an annual. Start indoors in March, transplant after all frost danger passes.
If you are unsure about your zone, check online or ask at a local nursery. They know the typical frost dates for your area.
Soil Temperature Matters More Than Air Temperature
Many gardeners make the mistake of planting based on air temperature alone. Lemongrass roots need warm soil to grow. The soil should be at least 60°F (15°C) at a depth of 2-3 inches.
Use a soil thermometer to check. If you do not have one, wait until nighttime temperatures stay above 50°F (10°C) for a week. This usually means the soil is warm enough.
Cold, wet soil will cause the stalks to rot. It is better to wait an extra week than to plant too early.
Starting Lemongrass Indoors
If you live in a cooler climate, starting lemongrass indoors gives you a head start. This is a reliable way to control the growing conditions.
Start seeds or stalks indoors 6-8 weeks before your last expected frost. Use small pots with drainage holes. Fill them with a light, well-draining potting mix.
How To Start From Stalks
Lemongrass is often grown from fresh stalks bought at the grocery store. This is easier than starting from seed. Here is how:
- Buy fresh lemongrass stalks with the root ends still attached.
- Place the stalks in a glass of water, root end down.
- Change the water every 2-3 days.
- After 1-2 weeks, roots and new shoots will appear.
- Once roots are 1-2 inches long, plant in a pot with soil.
- Keep the pot indoors in a sunny window until outdoor planting time.
This method works well and is very satisfying. You can see the roots grow before your eyes.
Starting From Seeds
Lemongrass seeds are small and slow to germinate. They need warmth and consistent moisture. Follow these steps:
- Sow seeds 1/4 inch deep in seed-starting mix.
- Keep the soil temperature between 70-80°F (21-27°C).
- Cover the pot with plastic wrap to hold humidity.
- Germination takes 10-21 days.
- Once seedlings have 2-3 true leaves, transplant to individual pots.
Seeds can be tricky. If you are new to gardening, starting from stalks is more reliable.
Transplanting Lemongrass Outdoors
When the weather is warm and stable, it is time to move your lemongrass outside. The exact date depends on your location, but here are the signs to look for:
- Night temperatures stay above 50°F (10°C) consistently.
- All danger of frost has passed.
- Soil temperature is at least 60°F (15°C).
- Daytime temperatures are regularly in the 70s or higher.
Harden off your plants first. This means gradually exposing them to outdoor conditions over 7-10 days. Start with a few hours of shade, then increase time and sunlight each day.
Spacing And Planting Depth
Lemongrass grows into large clumps. Space plants 24-36 inches apart. They need room to spread. If planting in rows, keep rows 3 feet apart.
Plant at the same depth as the pot. Do not bury the stalks too deep. The crown (where roots meet stems) should be just above soil level.
Water thoroughly after planting. Keep the soil moist but not soggy for the first few weeks.
Best Time To Plant In Different Regions
Here is a more detailed look at planting times for specific regions in the United States:
Southern States (Texas, Florida, California)
Plant from March through May. In frost-free areas, you can also plant in September for a fall harvest. Lemongrass grows year-round in warm parts of Florida and California.
Midwest And Northeast
Plant from late May to early June. The soil warms slowly here. Use black plastic or row covers to warm the soil faster if needed.
Pacific Northwest
Plant in late May or June. This region has cool, wet springs. Wait until the soil dries out a bit. Lemongrass does not like waterlogged soil.
Mountain And High Elevation Areas
Plant in June or even July. The growing season is short. Start indoors early and use containers that can be moved inside when frost threatens.
Growing Lemongrass In Containers
Container growing gives you more control over planting time. You can move pots indoors when the weather turns cold. This is ideal for gardeners in zones 5 and colder.
Plant in containers at any time from spring to early summer. Use a pot that is at least 12 inches wide and deep. Lemongrass has a large root system.
Make sure the container has drainage holes. Use a high-quality potting mix. Water regularly, as pots dry out faster than garden soil.
Overwintering Lemongrass In Containers
Before the first frost, move the container indoors. Place it in a sunny window or under grow lights. Reduce watering in winter. The plant will go semi-dormant but should survive until spring.
You can also dig up a clump from the garden and pot it for winter storage. This is a common practice in cold climates.
Common Mistakes When Planting Lemongrass
Even experienced gardeners make errors. Here are the most common ones and how to avoid them:
- Planting too early: Cold soil kills roots. Wait until the soil is warm.
- Planting too late: The plant needs 4-6 months of warm weather to mature.
- Overwatering: Lemongrass likes moisture but not standing water. Good drainage is essential.
- Underwatering: In hot weather, water deeply 2-3 times per week.
- Ignoring frost warnings: Cover plants or bring containers inside if frost is predicted.
Another mistake is not giving enough space. Lemongrass clumps can reach 4 feet tall and 3 feet wide. Crowded plants produce fewer stalks.
Harvesting Lemongrass
You can start harvesting about 3-4 months after planting. The stalks should be at least 1/2 inch thick at the base. Cut them at ground level with a sharp knife.
Harvest in the morning when the stalks are crisp. Leave at least 3-4 stalks on each clump so the plant can keep growing. Regular harvesting encourages new growth.
In warm climates, you can harvest multiple times during the growing season. In cooler areas, you may only get one main harvest before frost.
Frequently Asked Questions
Can I Plant Lemongrass In The Fall?
In frost-free zones (9-11), yes. Plant in early fall for a winter harvest. In colder zones, fall planting is too risky. The plant will not establish before winter.
How Late Can I Plant Lemongrass?
In most regions, plant no later than 2 months before the first expected frost. This gives the plant time to grow a strong root system. For zones 5-6, early June is the latest safe date.
Does Lemongrass Come Back Every Year?
In zones 8 and warmer, yes. It is a perennial. In colder zones, it is grown as an annual. You can overwinter it indoors if you have a container.
What Happens If I Plant Lemongrass Too Early?
The stalks may rot in cold, wet soil. Growth will be stunted. The plant may die if a late frost hits. Always wait for warm soil.
Can I Grow Lemongrass From Grocery Store Stalks?
Yes, this is a common method. Choose fresh stalks with the root end intact. Place them in water until roots grow, then plant. It works well.
Final Tips For Success
Timing is everything with lemongrass. Pay attention to your local weather, not just the calendar. Use a soil thermometer for accuracy.
If you are unsure, it is better to wait. Lemongrass grows fast in warm weather. Even a late planting can still produce a good harvest if summer is long and hot.
Mulch around the plants to keep soil warm and retain moisture. Use straw, wood chips, or grass clippings. Mulch also suppresses weeds.
Fertilize lightly every 4-6 weeks during the growing season. Use a balanced fertilizer like 10-10-10. Too much nitrogen makes the stalks weak and less flavorful.
Watch for pests like spider mites and aphids. They are rare but can appear in dry conditions. A strong spray of water usually knocks them off.
Lemongrass is a rewarding plant to grow. It adds flavor to teas, soups, and curries. It also repels mosquitoes naturally. With the right planting time, you will have a thriving clump all season long.
Remember the key point: plant after the last frost, when soil is warm. That simple rule will set you up for success. Happy gardening.