Lemongrass
Cymbopogon citratus
A tropical grass that will not survive a British winter outdoors anywhere, so it is grown in a pot and brought inside. It roots readily from a supermarket stem stood in water, which makes it one of the cheapest plants to acquire and one of the most satisfying.
- Position
- Bright with direct sun
- Water
- high demand
- Drainage
- Moisture-retentive
- Grows to
- 90–150 cm × 45–90 cm
- Hardiness
- H1C
- Harvest
- July to October
- Difficulty
- Some care needed
August
Harvest
Lemongrass’s year
Resolved for United Kingdom (general). Every window is stored against a climate event rather than a date, so a late frost pocket runs later than the band shows. What else August calls for.
| Activity | J | F | M | A | M | J | J | A | S | O | N | D |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Plant | April. | May. | ||||||||||
| Harvest | July. | August. | September. | October. | ||||||||
| Protect | October. |
Timing that travels
The band above resolves this plant's windows into months for one region. These are the windows themselves, stored against a climate event rather than a date — which is the form that survives being carried to a colder garden, a frost pocket, or next year.
What kind of herb this is
Herbs are a kitchen grouping rather than a botanical one, and the plants in it want opposite things. This is the one distinction that decides how to treat it.
Tropical, frost-tender herb
Growing regimesource
Sourced guidancehigh confidence
- Royal Horticultural Society: Lemongrass — growing
Checked 2026-08-13
Frost kills it outright. It has to come inside for winter or be treated as an annual, and the indoor months are survival rather than growth.
Treated the same way: curry leaf, lemon verbena, vietnamese coriander. The herb bed, split by regime
- Indoors
- Indoors to survive winter
Where the indoor assessment comes from
- IndoorsSourced guidancemoderate confidence
- Royal Horticultural Society: Lemongrass — growing indoors
Checked 2026-08-13
Almost any herb will sit on a windowsill in July. This is about whether it is still there in March, which is the part a pot on a supermarket shelf does not tell you.
What happens when it flowers
On a herb this is rarely a problem and rarely nothing. It is the point at which the plant stops being what you grew it for — by a lot, a little, or not at all.
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Lemongrass — harvesting
Checked 2026-08-13
Nothing to do about it. Flowering does not change what lemongrass is worth picking, so there is no reason to prevent it.
Conditions it needs
- Light
- Full sun
- Frost
- Frost tender
- Hardiness rating
- H1c (RHS)
- Survives down to
- 7–10 °CSourced guidanceDepends on conditions
- Grows best at
- 20–30 °C
- Soil
- Peat-free compost, Loam
- Soil pH
- 6–7.5
- Drainage
- Moisture-retentive
- Water needs
- high
- Drought
- poor tolerance
- Waterlogging
- moderate tolerance
- Heat
- good tolerance
- Wind and exposure
- poor tolerance
Where these figures come from
- LightSourced guidancehigh confidence
- Royal Horticultural Society: Lemongrass — position
Checked 2026-08-13
- FrostSourced guidancehigh confidence
- Royal Horticultural Society: Lemongrass — hardiness
Checked 2026-08-13
- Hardiness ratingSourced guidancemoderate confidence
- Royal Horticultural Society: RHS hardiness ratings
Checked 2026-08-13
- Survives down toSourced guidanceDepends on conditionshigh confidence
Applies when: Below roughly 7 °C it stops growing and begins to deteriorate. It does not need a frost to be lost — an unheated conservatory in January is enough.
- Royal Horticultural Society: Lemongrass — hardiness
Checked 2026-08-13
- Grows best atSourced guidancemoderate confidence
- Royal Horticultural Society: Lemongrass — temperature
Checked 2026-08-13
- SoilSourced guidancemoderate confidence
- Royal Horticultural Society: Lemongrass — soil
Checked 2026-08-13
- Soil pHSourced guidancemoderate confidence
- Plant Finder — Missouri Botanical Garden: Cymbopogon citratus — culture
Checked 2026-08-13
- DrainageSourced guidancemoderate confidence
- Royal Horticultural Society: Lemongrass — soil
Checked 2026-08-13
- Water needsHorticultural consensusmoderate confidence
In active growth. Much less in winter, when overwatering is the main risk.
No external citation — see the evidence type above.
Checked 2026-08-13
- DroughtHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- WaterloggingHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- HeatHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Wind and exposureHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
On your soil
Computed by comparing this plant's recorded requirements against each soil's recorded characteristics. A recorded horticultural fact overrides the comparison where GrowingHQ holds one.
| Soil | Verdict | Why |
|---|---|---|
| Heavy clay | Grows well here | Lemongrass grows perfectly well on heavy clay without special measures, though it is not the soil it would choose. |
| Sandy | Works, with one condition | Lemongrass will crop on sandy, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure. |
| Chalky and alkaline | Works, with one condition | Lemongrass will crop on chalky and alkaline, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure. |
| Loam | Prefers this soil | Loam suits Lemongrass as it stands: The pH suits it: it wants 6 to 7.5, and this soil is in that range. Loam is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering. |
| Silty | Grows well here | Lemongrass grows perfectly well on silty without special measures, though it is not the soil it would choose. |
| Peaty and acid | Grows well here | Lemongrass grows perfectly well on peaty and acid without special measures, though it is not the soil it would choose. |
| Shallow over rock | Works, with one condition | Lemongrass will crop on shallow over rock, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure. |
| Made ground and urban soil | Grows well here | Lemongrass grows perfectly well on made ground and urban soil without special measures, though it is not the soil it would choose. |
Not sure which you have? Four hand tests will settle it.
Space and spacing
- Mature height
- 90–150 cm
- Mature spread
- 45–90 cm
- Rooting depth
- 30 cm
Where these figures come from
- Mature heightHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Mature spreadHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Rooting depthHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
In a container
- Minimum volume
- 10 litres or more
- Minimum depth
- 25 cm
Where the container figures come from
- Minimum volumeHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Minimum depthHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
Grown in a pot by necessity rather than by choice, because the whole plant has to come indoors in October and a plant in open ground cannot. Use a large pot of rich moisture-retentive compost, stand it in a saucer of water through the summer, and keep it barely damp once it is inside.
Where and how you can grow it
Each way of growing is assessed separately, and “not assessed” is a real answer rather than a gap we have filled in with a guess.
| Method | Suitability | What it needs |
|---|---|---|
| Indoor pot | Well suitedsourceSourced guidancemoderate confidence
Checked 2026-08-13 | The brightest position available; A minimum of about 10 °C in winter |
| Windowsill | Well suitedsourceSourced guidancemoderate confidence
Checked 2026-08-13 | |
| Greenhouse | Well suitedsourceSourced guidancemoderate confidence
Checked 2026-08-13 | |
| Polytunnel | Well suitedsourceSourced guidancemoderate confidence
Checked 2026-08-13 | |
| Container | Well suitedsourceSourced guidancemoderate confidence
Checked 2026-08-13 | 10 litres; Moved under cover from October |
| Hydroponics | WorkablesourceGrowingHQ editorial positionmoderate confidence A wetland grass that takes readily to water culture and then makes a clump the size of a bucket, which is the whole of the difficulty.
Checked 2026-08-13 | |
| Open ground | Not suitablesourceSourced guidancemoderate confidence
Checked 2026-08-13 | Will not overwinter outdoors anywhere in Britain. |
Growing it
- PropagationStand a fresh supermarket stem with its base intact in a couple of centimetres of water on a warm windowsill. Roots appear within two to three weeks and it can then be potted up — much cheaper and more reliable than seed.
- HarvestingCut whole stems at the base rather than pulling. The swollen white section at the bottom is the part used in cooking; the leaves make a good tea but are too fibrous to eat.
- WateringLemongrass is a marsh grass and wants far more water than anything else in a herb bed — it is one of the few herbs that will sit happily in a saucer of water through the summer. Keep the compost genuinely wet from May to September and it grows fast. From October, once it is indoors and barely growing, cut back sharply and keep it only just damp: a cold wet pot in a dark room in January is what kills overwintered lemongrass.
- FeedingFeed generously through the summer — this is a grass making a great deal of bulk in one season, and a high-nitrogen or general-purpose liquid feed every fortnight from June to August produces the thick stem bases that are the part used. Stop feeding entirely from September; growth pushed late is soft and does not survive the move indoors.
- ProtectionLemongrass will not survive a British winter outdoors anywhere, and it is damaged well before frost — below about 7 °C it stops and starts to yellow. Bring the pot in during October, before the first cold nights rather than after them, and keep it somewhere bright and above 10 °C. Cut the foliage back by about half to reduce what the plant has to support, water sparingly, and expect it to look poor by February; it will come back once the light returns. A conservatory or a bright cool room suits it better than a warm dark one.
- PlantingPot rooted stems into a rich moisture-retentive compost in April or May and stand them outside in the sunniest, most sheltered place available once nights are reliably above 10 °C. Grow it in a pot rather than in the ground even where summers are warm, because the whole plant has to come indoors in autumn and a plant in open ground cannot.
Where this guidance comes from
- PropagationSourced guidancemoderate confidence
- Royal Horticultural Society: Lemongrass — propagation
Checked 2026-08-13
- HarvestingSourced guidancehigh confidence
- Royal Horticultural Society: Lemongrass — harvesting
Checked 2026-08-13
- WateringSourced guidancehigh confidence
- Royal Horticultural Society: Lemongrass — cultivation
Checked 2026-08-13
- FeedingSourced guidancehigh confidence
- Royal Horticultural Society: Lemongrass — cultivation
Checked 2026-08-13
- ProtectionSourced guidancehigh confidence
- Royal Horticultural Society: Lemongrass — overwintering
Checked 2026-08-13
- PlantingSourced guidancehigh confidence
- Royal Horticultural Society: Lemongrass — cultivation
Checked 2026-08-13
Is it worth putting under cover?
Whether it will grow there is on the methods table above. This is whether the space is well spent, which is a different question and usually the one being asked.
| Structure | What protection is worth | What decides it |
|---|---|---|
| Greenhouse | Only possible under coversourceGrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file.
Checked 2026-08-13 | Frost. Lemongrass is a tropical grass killed outright by a British winter and barely growing below about 15 °C. |
| Polytunnel | Extends the seasonsourceGrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file.
Checked 2026-08-13 | Overnight temperature. Glass holds overnight heat that polythene loses, so a tunnel runs cooler at night than a greenhouse in the same garden. For a crop at the edge of its heat requirement that difference decides whether the fruit ripens. |
On a windowsill
source
GrowingHQ editorial positionmoderate confidence
How long the crop is actually productive on an ordinary British windowsill without added light.
- GrowingHQ editorial synthesis — GrowingHQ
Checked 2026-08-13
Growing it without soil
Nearly anything can be grown in a soilless system by somebody with enough equipment. The useful question is whether it is worth it, in which technique, and what goes wrong.
Succeeds when the conditions listed here are met and fails when they are not. The conditions are the answer, not a caveat.
source
GrowingHQ editorial positionmoderate confidence
A wetland grass that takes readily to water culture and then makes a clump the size of a bucket, which is the whole of the difficulty.
- GrowingHQ editorial synthesis — GrowingHQ
Checked 2026-08-13
Techniques that suit it
- Deep water cultureRoots hang in aerated solution. Very productive and very unforgiving of solution temperature — warm solution holds less oxygen and root disease follows.
- Drip-fed mediumSolution is dripped into an inert medium around each plant. The most forgiving technique and the one that suits large, long-season, heavy crops.
source
Horticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- Root space
- Large for a herb — it forms a substantial fibrous clump.
- Lighting
- Needs supplementary light
- pH band
- 5.5–6.5
Where these figures come from
- Root spaceHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- LightingHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
- pH bandSourced guidancehigh confidence
Outside roughly this band, individual nutrients become unavailable even when they are present in the solution — which is why a crop can starve in a full reservoir.
- Purdue Extension — Purdue University: Hydroponic solution management — pH
Checked 2026-08-13
What actually goes wrong
- Warm solution. Above roughly 22 °C the water holds much less dissolved oxygen and root disease follows quickly, which is why summer is harder than winter in an indoor system.
source
Sourced guidancemoderate confidence
- Purdue Extension — Purdue University: Solution temperature and dissolved oxygen
Checked 2026-08-13
No nutrient recipes here
GrowingHQ records pH bands, which are measurable properties of nutrient availability, and deliberately records no EC or PPM targets and no mixing instructions. Published targets vary by cultivar, growth stage, water source and technique, and the figures that apply to your system are on the product you bought.
Harvesting
- When it is readyA stem is ready when its base has swollen to about the thickness of a finger and feels firm and solid rather than papery — usually from the second half of the summer, and only from a plant that has had a full warm season. Take stems from the outside of the clump and leave the centre growing.
- How to pick itTwist and pull an outer stem away from the clump at the base, or cut it at soil level. Trim the leafy top off — the swollen base is the part used — and keep the top for infusing.
Where the harvest guidance comes from
- When it is readySourced guidancehigh confidence
- Royal Horticultural Society: Lemongrass — harvesting
Checked 2026-08-13
- How to pick itHorticultural consensusmoderate confidence
No external citation — see the evidence type above.
Checked 2026-08-13
What goes wrong
| Problem | How often | Notes |
|---|---|---|
| Aphids | occasionalsourceHorticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13 | |
| Foliage that is meant to look like that | commonsourceHorticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13 | Every leaf leaves the sheath as a tight rolled spear and opens as it extends, which is read as damage by anybody meeting the plant for the first time. |
Safety and edibility
Listed as harmful to cats or dogs
Lemongrass is listed as harmful if eaten. The essential oils and cyanogenic glycosides in the leaves cause vomiting and digestive upset. Cats are the greater concern: they are drawn to the grassy leaves and lack the liver enzymes to process concentrated plant oils efficiently. In quantity the fibrous leaves can also physically obstruct the gut.source
Sourced guidancehigh confidence
- ASPCA Animal Poison Control Center — toxic and non-toxic plant list — American Society for the Prevention of Cruelty to Animals: Cymbopogon citratus — toxic plants list
Checked 2026-08-13
Affected parts: leaf.
- Pets and livestockpetsListed as toxic to cats and dogs. The essential oils and cyanogenic glycosides in the leaves cause vomiting and digestive upset, and cats are the greater concern — they are drawn to grassy foliage and process concentrated plant oils poorly. Eaten in quantity the tough fibrous leaves can also physically obstruct the gut.
source
Sourced guidancehigh confidence
- Royal Horticultural Society: Plants harmful to pets
Checked 2026-08-13
Keep the pot out of reach of cats, which is the opposite of where a kitchen herb usually lives. Tell a vet what was eaten rather than waiting to see whether it settles.
Sources for this page
GrowingHQ editorial synthesis · Plant Finder · Royal Horticultural Society
Each figure on this page carries its own citation, under the “where these figures come from” note in its section. Record last reviewed 2026-08-14.
If something is wrong with it
- Brown, crisp leaf tips — 2 causes GrowingHQ holds for lemongrass
Something else? Work through it with the diagnostic tool.