A tropical grass that doubles as a dramatic ornamental clump. Harvest stalks for curries, soups, and teas. In warm zones it's a large perennial -- in cold zones, grow in a pot and bring indoors in winter.
Plant window opens
Jun 11
Last chance to plant
Jul 9
Last frost
~May 1
Days to harvest
90–120 days
Difficulty
Easy
Wrong season — Zone 4
Harvest: Sep
Harvest urgency: weekly— Harvest window lasts several weeks
Planting Calendar
In Zone 4, Lemongrass can be planted outdoors from Jun 11 — the window closes around Jul 9.
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
plant
harvest
harvest
care
prune
harvest
prune / care
Container growing. Move outdoors once nights stay above 50°F. Bring in before first frost.
Your zone at a finer grainNOAA 1991–2020
Zone 4 is split into two subzones. The a/b distinction affects your exact last frost date by 1–2 weeks -- meaningful for heat-sensitive crops and fruit tree hardiness.
Subzone
Last frost
First fall
Season
Min temp
4a
May 7
Oct 6
~150 days
-30 to -25°F
4b
May 3
Oct 11
~160 days
-25 to -20°F
plant detects your subzone from your location and adjusts planting windows accordingly.
Growing Journey
Here is what to expect at each stage — and what to do when you get there.
PlantingDay 0-21
Most perennial herbs prefer poor, well-drained soil -- do not over-fertilise. Good drainage is more important than rich
EstablishmentDay 14-60
Water regularly in the first season to establish roots. Once established, most perennial herbs are drought-tolerant.
HarvestYear 0-1
Harvest by cutting stems back by a third. Never cut into old woody growth on rosemary, sage, and thyme -- they do not re
WinterYear 0-1
Give a light haircut before winter to tidy up but avoid heavy pruning -- leave it for spring. Mulch around the base in c
Spring CutbackYear 1-1
Cut back last year's growth by about half once new growth appears. This annual cutback keeps perennial herbs from going
What to Expect
Typical yield
Multiple stalks per plant -- divide every 2-3 years
Lemongrass is surprisingly easy to grow in a pot. Fresh lemongrass is incomparably better than dried.
Key factorsoverwintering indoorspot sizedivision
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Grown Lemongrass before?or
Care Guide
Sunlight
Full sun · 6–8 hrs/day
Watering
Moderate
Spacing
24–36 inches
Soil
Well-draining, fertile, moisture-retentive
Days to maturity
90–120 days
Soil pH
5.5–7.0
Plant tip · Zone 4
Container growing. Move outdoors once nights stay above 50°F. Bring in before first frost.
Lifecycle
Perennial
How to know it's ready
Harvest outer stalks at ground level when 12+ inches tall. Inner white stalk is used for cooking.
Watering Lemongrass
How often
Every 3-4 days
How much
1-2 inches per week
Method
At soil level
Overwatering signs
Yellowing, root rot
Underwatering signs
Brown leaf tips, slow growth
Feeding Schedule
How often
monthly
Feed type
Nitrogen-rich fertilizer
Key timing
throughout growing season
NPK: high N for leafy growth, e.g. 10-5-5
Tropical grass that loves nitrogen. Feed monthly during the growing season. Reduce feeding in autumn.
Example product: Fish emulsion
Reminder: every 28 days after feeding
Seasonal Care
Mar
Cut Back
Cut back to 6 inches in early spring. In zones below 9, dig up and overwinter indoors in a pot before first frost.
Division
Divide existing clumps or buy as plants. Can start from seed but very slow.
Container friendly · Minimum 5 gallons
Excellent container plant -- grow in pots and bring indoors before frost in zones below 9. 5-gallon minimum for good yield.
Companion Planting
Some plants help Lemongrass thrive. Others compete or cause problems.
Grows well with
BasilMarigolds
Keep apart from
Fennel
Common Problems
Something went wrong? Here is what likely happened and what to do differently next time.
Frost or cold damage
What happened: Cold or frost at a vulnerable moment -- germination, seedling stage, or transplant -- can set back or kill plants that are not yet established enough to handle it.
Next season: Know your last frost date and work from it. Cover vulnerable plants with fleece when frost threatens, especially in the first few weeks after planting out.
Pests or disease
What happened: Most pest and disease problems are manageable if caught early. Regular checking -- especially undersides of leaves -- is the most effective prevention.
Next season: Check plants weekly and act at the first sign of a problem. Remove affected material promptly. Healthy, well-fed plants in good conditions resist pests better than stressed ones.
Too much water
What happened: Overwatering is one of the most common causes of plant failure. Roots need oxygen as well as moisture -- waterlogged soil suffocates them.
Next season: Water deeply but less often rather than a little every day. Most plants prefer to dry out slightly between waterings. Good drainage is as important as watering.
Too little water
What happened: Drought stress causes wilting, reduced production, and makes plants more susceptible to pest and disease. Stress at critical moments -- germination, flowering, fruiting -- causes the most damage.
Next season: Mulching around plants is the single most effective way to retain soil moisture and reduce watering frequency.
Not enough sun
What happened: Most vegetables and fruits need 6-8 hours of direct sun. In less light they grow slowly, produce poorly, and are more vulnerable to disease.
Next season: Observe your garden through the day and map where the sun falls at different times. Match crops to the light levels available -- shade-tolerant crops for shaded spots, sun-lovers for the brightest beds.
What went wrong
Something didn't work out? Here is what likely happened and what to do differently next season.
Frost or cold damage
What happened: Cold or frost at a vulnerable moment -- germination, seedling stage, or transplant -- can set back or kill plants that are not yet established enough to handle it.
Next season: Know your last frost date and work from it. Cover vulnerable plants with fleece when frost threatens, especially in the first few weeks after planting out.
Pests or disease
What happened: Most pest and disease problems are manageable if caught early. Regular checking -- especially undersides of leaves -- is the most effective prevention.
Next season: Check plants weekly and act at the first sign of a problem. Remove affected material promptly. Healthy, well-fed plants in good conditions resist pests better than stressed ones.
Too much water
What happened: Overwatering is one of the most common causes of plant failure. Roots need oxygen as well as moisture -- waterlogged soil suffocates them.
Next season: Water deeply but less often rather than a little every day. Most plants prefer to dry out slightly between waterings. Good drainage is as important as watering.
Too little water
What happened: Drought stress causes wilting, reduced production, and makes plants more susceptible to pest and disease. Stress at critical moments -- germination, flowering, fruiting -- causes the most damage.
Next season: Mulching around plants is the single most effective way to retain soil moisture and reduce watering frequency.
Not enough sun
What happened: Most vegetables and fruits need 6-8 hours of direct sun. In less light they grow slowly, produce poorly, and are more vulnerable to disease.
Next season: Observe your garden through the day and map where the sun falls at different times. Match crops to the light levels available -- shade-tolerant crops for shaded spots, sun-lovers for the brightest beds.
Pests & Diseases
Know what to look for before it gets out of hand — early identification is the most important step.
Spider mites
pestmedium
What to look for
Fine yellow or white stippling on leaves. Fine webbing along leaf edges and between blades in heavy infestations. Leaves bronze and dry out. Most severe on indoor or potted plants and during hot dry summers.
Cause
Two-spotted spider mite (Tetranychus urticae) is the primary species. UF/IFAS notes spider mites are the most common lemongrass problem and are mostly a concern on indoor plants where humidity is low.
Organic treatment
Rinse plants with a forceful water spray, focusing on leaf undersides. Insecticidal soap or horticultural oil applied weekly for 2-3 weeks. Increase humidity around indoor plants.
Prevention
Keep plants well-watered during hot weather. Mist indoor plants or run a humidifier. Avoid dusty conditions -- dust on leaves favors mite buildup.
Mealybugs
pestlow
What to look for
White cottony masses in leaf axils and between stalks at the base of the clump. Sticky honeydew and sooty mold on lower leaves. Clump weakens and grows slowly.
Cause
Several mealybug species feed on lemongrass, most often on potted or greenhouse plants where natural predators are absent.
Organic treatment
Dab colonies with a cotton swab dipped in rubbing alcohol. Insecticidal soap or horticultural oil sprayed into the base of the clump. Severe infestations on potted plants: cut the clump back hard and repot in fresh soil.
Prevention
Inspect new plants before bringing them home or indoors. Keep the base of the clump clear of dead leaf sheaths where mealybugs hide.
Leaf-feeding caterpillars
pestlow
What to look for
Ragged chewed edges on leaf blades. Caterpillar frass visible between blades. Rarely enough damage to affect plant health, since lemongrass regrows quickly.
Cause
Various Lepidoptera larvae occasionally feed on lemongrass foliage. UF/IFAS and PlantVillage (summarizing Gilman 1999) list these as a minor, sporadic issue.
Organic treatment
Hand-pick caterpillars. Bt (Bacillus thuringiensis) for persistent infestations -- effective on caterpillars, safe for beneficials.
Prevention
Generally not needed. Healthy established clumps outgrow caterpillar damage.
Leaf blight
diseaselow
What to look for
Reddish-brown spots on leaf tips and margins. Affected leaves look prematurely dried. Heavy pressure can reduce harvestable foliage but rarely threatens the clump.
Cause
Several fungal pathogens, including Curvularia and Helminthosporium species, cause leaf blight on Cymbopogon. Favored by prolonged leaf wetness in humid weather.
Organic treatment
Hand-remove blighted leaves. Copper fungicide only if infection is severe and positively identified -- UF/IFAS notes lemongrass rarely requires disease treatment.
Prevention
Avoid overhead watering. Space clumps for airflow. Remove and compost old dry leaves in spring.
Rust
diseaselow
What to look for
Orange or reddish-brown pustules on leaf undersides that release powdery spores when rubbed. Leaves yellow and dry back from tips in heavy infections.
Cause
Puccinia nakanishikii and related rust fungi specific to grasses. Favored by warm humid weather and overcrowded clumps.
Organic treatment
Cut the clump back hard and dispose of rusted foliage. New growth typically comes in clean.
Prevention
Divide crowded clumps every 2-3 years. Water at soil level. Provide full sun and good airflow.
Recommended Varieties
East Indian Lemongrass (Cymbopogon flexuosus -- most flavourful)
West Indian Lemongrass (Cymbopogon citratus -- most widely grown)
Both species work for cooking. West Indian is more widely available; East Indian has slightly more intense citral oil content.
Crop Rotation — rotate every 0 years
Perennial -- no annual rotation
Avoid planting after: N/A -- permanent planting
Good to follow: N/A -- permanent planting
Fruit trees and perennial shrubs are permanent plantings -- crop rotation does not apply. Choose the planting site carefully as it is permanent.
Storing Your Harvest
Room temp
1-2 weeks in a glass of water
Fridge
2-3 weeks wrapped
Freezer
Freeze whole stalks -- peel outer layers before using frozen
Lemongrass freezes very well. Freeze extra stalks whole -- slice directly from frozen.
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Weather watch
plant monitors these conditions and sends an alert the moment they are forecast for your location.
Frost Warning
Frost warning -- protect tender herbs
Basil, cilantro, and lemongrass are extremely frost-tender. Bring containers inside or cover with fleece tonight. Hardy herbs like thyme, rosemary, and mint are much more frost-tolerant.
HIGH priority
Heat Stress
Heat alert -- herbs may bolt
Heat triggers bolting in cilantro, dill, and parsley. Harvest as much as possible before temperatures peak. Basil, on the other hand, loves heat -- just remove any flowers that appear.
MEDIUM priority
Moon phase planting
Traditional growers have used lunar cycles to time planting and harvest for centuries. The moon affects moisture levels in soil and sap flow in plants.
Above-ground crop
Waxing moon -- new moon to full moon
Plant and harvest on a waxing moon. Energy draws upward into leaves, stems, and fruit. Germination is strongest in the days after the new moon.
Lunar phase guide
New moon → Full moon
Waxing phase
Best for planting above-ground crops. Sap rises, germination is stronger. Good for transplanting.
Full moon → New moon
Waning phase
Best for harvesting, pruning, and root crops. Energy draws downward. Good for dividing perennials.
Full moon
Peak moisture
Avoid planting -- seeds may rot in high-moisture conditions. Good for harvesting crops to eat fresh.
New moon
Rest period
Avoid planting or transplanting. Best for soil preparation, weeding, and composting.
Common questions
In Zone 4, direct sow lemongrass outdoors Jun 11 - Jul 9 after your last frost of approximately May 1. Container growing. Move outdoors once nights stay above 50°F. Bring in before first frost.
Zone 4 has an average last spring frost around May 1 and a first fall frost around Oct 1. These vary by location — the plant app uses your ZIP code with NOAA data for precision.
Good companions for lemongrass include Basil, Marigolds. Avoid planting near Fennel.
Lemongrass typically takes 90–120 days to harvest in Zone 4. Expected harvest window: Sep.
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