How to Grow Lemongrass from Seed (Step by Step)

Lemongrass grows well from seed if you give it warmth, light, and a head start indoors.

To grow lemongrass from seed, press the seeds onto the surface of moist seed-starting mix about 8 weeks before your last frost, keep them at 70 to 80°F until they sprout in one to three weeks, then plant the young clumps outside once nights stay above 60°F.

The seed is tiny and slow at first, and germination is often patchy. Once summer heat arrives, though, those thin blades turn into a big fountain of citrus-scented leaves.

With the right timing, you can be cutting leaves for tea by midsummer and pulling thick stalks for cooking by late summer.

Seed-to-Harvest Timeline at a Glance

Growing lemongrass from seed takes about four to five months from sowing to your first thick stalks, with leaf harvests starting sooner. Use this table to plan your weeks.

Stage	When It Happens	What You Do
Sow seeds	About 8 weeks before last frost	Surface-sow on moist mix at 70 to 80°F
Germination	1 to 3 weeks after sowing	Keep mix damp; add strong light once sprouts appear
Thin seedlings	When sprouts are about 1 inch tall	Snip extras, leaving small groups
Pot up clumps	4 to 6 weeks after sowing	Move clumps to 3- or 4-inch pots
Harden off	7 to 10 days before planting	Build up outdoor time slowly
Plant out	Nights stay above 60°F	Full sun, well-drained soil or a large pot
First leaf harvest	Plants reach 12 inches or taller	Snip outer blades for tea
First stalk harvest	Late summer	Cut outer stalks about 1/2 inch thick

Harvesting lemongrass stalks takes the longest because the bases need hot weather to swell. In short-summer areas, expect thinner stalks the first year.

When Should You Start Lemongrass Seeds?

Start lemongrass seeds indoors about 8 weeks before your average last frost date. That gives seedlings time to form small clumps before nights warm up enough for planting.

Your region changes the calendar quite a bit, so set your date by your own frost dates and night temperatures.

Count Back Eight Weeks from Your Last Frost

Find your average last frost date, then count back 8 weeks on the calendar. That’s your sowing week.

If your last frost is May 10, sow around March 15. If it’s April 1, sow in early February.

I like the 8-week window because lemongrass seedlings grow slowly in their first month. Some seed packets suggest only 3 weeks, but that leaves you with tiny plants at planting time.

Starting too early has its own cost, since you’ll be growing lemongrass indoors under lights for months in cramped pots.

Keep in mind that your last frost date is a starting point. Lemongrass shouldn’t go outside until nights stay above 60°F, which in many places comes 2 to 4 weeks after the last frost.

Adjust the Schedule for Your US Region

Here’s how I’d time it in different parts of the country:

• Northeast and Midwest (zones 4 to 7): Sow mid-March to early April. Plant out in late May or early June, once nights hold above 60°F.
• Southeast (zones 7 to 9): Sow in late January or February. Plant out in April.
• Florida, South Texas, and Southern California (zones 10 to 11): Sow in late winter or early spring. Lemongrass is perennial here, so plants can stay in the ground for years.
• Southwest low desert: Sow in January and plant out by March, before the extreme heat. Afternoon shade helps young plants in summer.
• Pacific Northwest: Sow in early April. Cool nights last into June, so many gardeners keep plants in containers on a warm patio.

In zones colder than 9, you’ll treat lemongrass as an annual or bring it inside before nights drop below 50°F.

What You Need Before Sowing

You need fresh seed of the right species, a shallow tray, fine seed-starting mix, gentle bottom heat, and a strong light source. Getting these ready before sowing day keeps the tiny seeds from sitting in cold, dim conditions while you shop.

Choose Seeds Labeled with the Right Species

Check the botanical name on the packet. West Indian lemongrass, Cymbopogon citratus, is the classic cooking type with fat, tender stalk bases.

East Indian lemongrass, Cymbopogon flexuosus, is a close cousin. It’s a bit more compact and is often grown for oil, though its leaves still make good tea.

Many seed packets sold in the US are C. flexuosus, so read the label if thick stalks for cooking are your goal.

Buy seed packed for the current year. Lemongrass seed loses viability fairly fast, and old seed is one of the top reasons nothing sprouts.

Plan on low germination. Even fresh lemongrass seed often comes up at about 50%, so sow more than you think you need.

Set Up Trays, Seed-Starting Mix, Heat, and Light

Here’s my basic setup:

• Tray or cells: A shallow flat or 6-cell inserts with drainage holes, plus a clear humidity dome.
• Seed-starting mix: A fine, sterile mix. Skip garden soil, which crusts and carries disease.
• Seedling heat mat: This holds the mix near 75°F, which matters in cool basements or spring kitchens.
• Thermostat (optional): Plugs into the mat and stops it from overheating.
• LED grow light: A sunny window rarely gives enough light in March. A shop-style LED hung 2 to 4 inches above seedlings works well.
• Spray bottle: Misting keeps the seeds in place.
• Vermiculite (optional): A light dusting holds seeds steady.
• Labels: Write the species and sowing date.

Step 1: Sow Seeds on the Surface

Sow lemongrass seeds on top of the mix and press them in lightly, with no more than a thin dusting on top. Light helps these seeds germinate, so this is the step where most failures start.

If you’re learning how to grow lemongrass from seeds for the first time, get this part right and the rest gets easier.

Moisten the Mix and Press Seeds into Place

Wet the seed-starting mix before you sow. Squeeze a handful; it should hold together without dripping, like a wrung-out sponge.

Fill your cells or tray to about 1/4 inch from the top and firm the surface gently with your fingers.

Scatter lemongrass seeds thinly across the surface. Since the seed is so fine and germination is low, I’d drop 4 to 6 seeds in each cell.

Press the seeds down with a flat hand or the bottom of a cup so they touch the damp mix. Good contact lets them soak up water.

Mist the surface, set the dome on top, and label the tray.

Why a Deep Cover Can Prevent Sprouting

Lemongrass seeds are small and carry little stored energy. Buried at 1/4 inch, a sprout can run out of fuel before it reaches the surface.

Seed packets commonly list a depth of 1/16 inch, and some say no deeper than 1/8 inch. I press the seeds down and leave them uncovered.

If you want a cover, use a light sprinkle of vermiculite. It lets light through and keeps seeds from washing around when you water.

Step 2: Keep Seeds at 70 to 80°F and Evenly Moist

Lemongrass needs steady warmth between 70 and 80°F and a constantly damp surface to sprout. Seeds that cool down at night or dry out for even a day often stall. Bottom heat and a humidity dome handle both jobs with little effort.

Use Bottom Heat Without Overheating the Tray

Set the tray on a seedling heat mat. Most mats warm the mix about 10 to 20°F above room temperature, which is enough in a 60°F room.

Push a soil thermometer into one cell to check. You’re aiming for 70 to 80°F, with about 75°F as the sweet spot.

A thermostat controller keeps things steady. Without one, a mat in a warm room can push the mix into the high 80s and dry the surface fast.

Once most seedlings are up, turn the heat off or lower it. At that point, strong light helps them more than extra warmth.

Keep the Surface Damp, Not Soggy

The top layer, where the seeds sit, is the part that must never dry. Check it once or twice a day.

Mist when the surface looks lighter in color. Bottom watering also works: set the tray in an inch of water for 10 to 15 minutes, then drain it.

Avoid pouring water from a can. It washes tiny seeds into clumps or buries them.

Soggy mix starves the seeds of air and invites mold. If water beads on the inside of the dome all day, prop one corner open for an hour.

Step 3: Watch for Germination over One to Three Weeks

Most lemongrass seeds sprout in 7 to 21 days at the right temperature, and some trays take a little longer. Expect the first few to appear well before the rest, so stay patient.

What New Sprouts Look Like

New lemongrass seedlings look like fine green threads, thinner than a pencil lead. They’re easy to mistake for a blade of lawn grass or a mold strand.

Each sprout has a single narrow leaf. A second and third blade follow over the next couple of weeks.

As soon as the first sprouts show, take the dome off for part of the day and put the tray under your LED grow light. Seedlings that stay under a closed dome stretch and get weak.

How to Handle Uneven Emergence

Patchy germination is normal for lemongrass. You might see three sprouts in one cell and none in the next.

Keep the empty cells warm and moist for a full 3 weeks before giving up on them. Late seeds still make healthy plants.

If one cell is full and its neighbor is bare, leave both alone for now. You can tease apart and share a crowded group later when you pot up.

If almost nothing comes up after 3 weeks, check the troubleshooting tips further down before reseeding.

Step 4: Thin Seedlings and Pot Up Small Clumps

Thin crowded cells to small groups of 2 or 3 seedlings, then move each group into its own pot once roots hold the mix together.

Lemongrass seedlings grow into fuller transplants when you keep a few together, since a group fills out into a clump faster than a single blade.

Give Seedlings Strong Light

Seedlings need 14 to 16 hours of bright light a day. Put your LED grow light on a timer and hang it 2 to 4 inches above the tops.

Raise the light as plants grow. If leaf tips look pale or scorched, move it up an inch.

A south-facing window helps, but on its own it’s usually too weak in early spring. Rotate the tray daily if you use a window.

When seedlings reach about 1 inch tall, snip extras at soil level with small scissors. Pulling them can tear the roots of the ones you keep.

Move Established Clumps Without Damaging Their Roots

Pot up when seedlings are about 3 inches tall or when roots poke out of the drainage holes. This is usually 4 to 6 weeks after sowing.

1. Water the cells an hour before so the root ball holds together.
2. Fill a 3- or 4-inch pot with moist potting mix.
3. Push the cell from below and lift out the whole plug. Avoid pinching the thin stems.
4. Set the plug at the same depth it grew before, then firm the mix around it.
5. Water gently and put the pot back under lights.

Start feeding with a half-strength balanced liquid fertilizer every 2 weeks after potting up. Young grass plants are hungry for nitrogen.

Step 5: Harden Off and Plant After Nights Stay Above 60°F

Plant lemongrass outside only after a 7- to 10-day hardening-off period and once night temperatures stay above 60°F. Cold nights stall this tropical grass for weeks, so waiting an extra week pays off.

The site should get full sun and have well-drained soil, or you can use a large container you can move.

Introduce Seedlings to Outdoor Sun Gradually

Indoor seedlings burn and dry out if you move them straight into full sun. Hardening off toughens them up slowly.

• Days 1 to 2: One to two hours outside in bright shade, out of the wind.
• Days 3 to 4: Three to four hours, with an hour of morning sun.
• Days 5 to 7: Half the day outside, adding more direct sun.
• Days 8 to 10: All day in full sun, and overnight if nights are above 60°F.

Check the pots often. Small pots dry quickly in sun and wind.

Choose a Sunny, Well-Drained Bed or Large Container

Lemongrass needs at least 6 hours of direct sun. Here’s more on how much sun lemongrass needs in different climates.

In the ground, mix compost into the planting area and space clumps 18 to 24 inches apart. Lemongrass can grow 3 to 5 feet tall in one summer.

For lemongrass in containers, I’d use at least a 5-gallon pot with drainage holes, and bigger is better. You can grow lemongrass in pots and roll them indoors in fall, which makes containers my top pick north of zone 9.

Plant at the same depth the clump grew in its nursery pot, then water deeply.

Care for New Transplants Through Summer

Keep the soil evenly moist during the first month, and keep watering regularly after that. Lemongrass is a thirsty plant, and drought stress makes leaves brown and stalks thin.

Feed every 2 to 3 weeks in summer with a nitrogen-rich or balanced fertilizer. A 2-inch layer of mulch holds moisture in beds.

Pull weeds while plants are small. By July, clumps shade them out.

If you have pets, the ASPCA lists lemon grass as toxic to cats, dogs, and horses, mainly causing stomach upset if they eat a lot. My lemongrass care guide covers summer feeding and fall prep in more detail.

Should You Start with Seeds, Stalks, or a Nursery Plant?

Seeds are the cheapest way to get many plants, a nursery plant is the fastest path to harvest, and grocery stalks sit in between. Your choice comes down to budget, how long your summer is, and how many clumps you want.

Compare Cost, Availability, and Time to Harvest

Factor	Lemongrass Seeds	Grocery Stalks	Nursery Plant
Cost	$3 to $5 per packet	$2 to $4 per bundle	$5 to $15 per pot
Plants per purchase	Dozens	3 to 6	1
Time to stalk harvest	4 to 5 months	3 to 4 months	2 to 3 months
Success rate	Low to moderate	Moderate	High
Species certainty	Labeled on packet	Usually C. citratus	Labeled on tag

Lemongrass stalks from an Asian market are almost always the cooking type. You can regrow lemongrass from store-bought stalks by rooting them in water for 2 to 3 weeks. Pick stalks with the bulb base still attached, since trimmed bottoms won’t root.

Choose the Best Starting Method for a Short Growing Season

In zones 3 to 6, summer heat is short. I’d lean toward a nursery plant or rooted stalks so you get thick stalks before fall.

If you want seed, start on the early side of the 8-week window and pot up into gallon containers before planting out. Bigger transplants give you a head start.

Seed makes the most sense when you want several clumps for edging, tea, and cooking. A packet of seed costs about the same as one nursery pot.

Troubleshoot Seeds That Won’t Sprout or Seedlings That Falter

Most lemongrass seed problems trace back to cold, deep sowing, old seed, or too much water. Seedlings that do sprout tend to fail from rot or weak light. Each problem has a clear fix.

No Sprouts: Check Seed Age, Temperature, and Sowing Depth

Start with the packet date. Seed more than a year old often has very poor germination.

Next, check the temperature. Mix below 68°F slows or stops germination, even if the room feels warm to you.

Then think about depth. Seeds covered with 1/4 inch of mix often never reach light. Resow on the surface with a light press.

Give each batch at least 3 weeks before judging it.

Damping Off: Reduce Excess Moisture and Improve Airflow

Damping off is a fungal problem that makes seedlings pinch at the base and flop over. Once a seedling collapses, it won’t recover.

• Remove the dome once most seeds sprout.
• Run a small fan on low a few feet away for gentle air movement.
• Water from below and let the top dry slightly between waterings once seedlings are up.
• Use fresh sterile mix and clean trays for each new batch.

Remove fallen seedlings right away to slow the spread.

Leggy Seedlings: Move the Light Closer

Tall, floppy seedlings that lean are reaching for light. This is the most common problem when growing lemongrass indoors on a windowsill.

Lower your LED grow light to 2 to 4 inches above the tops and run it 14 to 16 hours a day. Cooler room temperatures, around 65 to 70°F after germination, also keep growth sturdy.

Older plants that yellow or brown in summer are a different issue. My post on why a lemongrass plant is dying covers those causes.

When Can You Take the First Harvest?

You can start harvesting lemongrass leaves once plants reach about 12 inches tall, usually 6 to 8 weeks after planting out. Stalks take longer, and they’re ready in late summer when the bases reach about 1/2 inch across.

Wear gloves, since the leaf edges are sharp.

Harvest Leaves Before the Stalk Bases Thicken

Lemongrass leaves are packed with citral, the compound behind the lemony scent and the main part of lemongrass essential oil. That makes them great for tea while you wait on stalks.

Snip outer blades a few inches above the base with clean scissors. Leave the center blades alone so the clump keeps growing.

Cut leaves into 2-inch pieces and steep them in hot water, or dry them for winter tea. Fresh leaves keep a week or two in the fridge.

Cut Mature Outer Stalks Without Removing the Whole Clump

For lemongrass in cooking, the pale, swollen base is the part you want. Wait until outer stalks are about 1/2 inch thick, which often happens in August or September.

Choose stalks at the edge of the clump. Cut them at soil level or bend and twist them free.

Take no more than one-third of the clump at a time. Peel the tough outer layers and use the lower 4 inches.

To keep plants over winter, grow lemongrass indoors in a bright window, and see how to harvest lemongrass for storage tips.

Frequently Asked Questions