Herbperennial herbStraightforward

Lemon balm

Melissa officinalis

A hardy perennial with a strong lemon scent, chiefly used for tea, and one that self-seeds hard enough to become a nuisance in a border. Cut it back before it sets seed and it is well behaved; let it flower once and there will be seedlings across the garden for years.

Position: Full sun or Partial shade or Dappled shade
Water: low demand
Drainage: Free-draining, Moisture-retentive
Grows to: 60–90 cm × 45–60 cm
Hardiness: H6
Harvest: May to September
Difficulty: Straightforward

August

Harvest

Coming next month: divide.

Lemon balm’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	M	A	M	J	J	A	S
Sow under cover	March.	April.
Harvest			May.	June.	July.	August.	September.
Divide	March.	April.					September.

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.

Moisture-loving perennial herb

Growing regime

source

Sourced guidancehigh confidence

Royal Horticultural Society: Lemon balm — growing

Checked 2026-08-13

Wants damp ground and tolerates shade, which is the opposite of the Mediterranean set. Most will spread if allowed to, so the question is usually containment rather than establishment.

Treated the same way: chives, fennel, garlic chives, lovage, mint, sorrel. The herb bed, split by regime

Indoors: Indoors spring to autumn

Where the indoor assessment comes from

IndoorsSourced guidancemoderate confidence: Royal Horticultural Society: Lemon balm — 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.

Leaves coarsen

source

Sourced guidancehigh confidence

Royal Horticultural Society: Lemon balm — harvesting

Checked 2026-08-13

Cut back hard as it flowers, both for fresh leaves and because lemon balm seeds itself around freely if the flowers are left to set.

source

Sourced guidancemoderate confidence

Royal Horticultural Society: Lemon balm — care

Checked 2026-08-13

Conditions it needs

Light: Full sun, Partial shade, Dappled shade
Frost: Very hardy
Hardiness rating: H6 (RHS)
Grows best at: 12–25 °C
Germinates at: 15–25 °C
Soil: Loam, Clay, Sandy, Chalky
Soil pH: 5.5–7.5
Drainage: Free-draining, Moisture-retentive
Water needs: low
Drought: moderate tolerance
Waterlogging: moderate tolerance
Heat: good tolerance
Wind and exposure: good tolerance

Where these figures come from

LightSourced guidancemoderate confidence: Royal Horticultural Society: Lemon balm — position
Checked 2026-08-13
FrostSourced guidancehigh confidence: Royal Horticultural Society: Lemon balm — hardiness
Checked 2026-08-13
Hardiness ratingSourced guidancemoderate confidence: Royal Horticultural Society: RHS hardiness ratings
Checked 2026-08-13
Grows best atSourced guidancemoderate confidence: Royal Horticultural Society: Lemon balm — temperature
Checked 2026-08-13
Germinates atSourced guidancemoderate confidence: Royal Horticultural Society: Seed germination temperatures
Checked 2026-08-13
SoilSourced guidancemoderate confidence: Royal Horticultural Society: Lemon balm — soil
Checked 2026-08-13
Soil pHSourced guidancemoderate confidence: Plant Finder — Missouri Botanical Garden: Melissa officinalis — culture
Checked 2026-08-13
DrainageSourced guidancemoderate confidence: Royal Horticultural Society: Lemon balm — soil
Checked 2026-08-13
Water needsHorticultural consensusmoderate confidence: 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	Works, with one condition	Lemon balm will crop on heavy clay, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. A plant that stays in the ground through winter with its roots in cold, saturated soil rots — which is what kills most of what fails on heavy ground, rather than the cold.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse.
Sandy	Prefers this soil	Sandy suits Lemon balm as it stands: The pH suits it: it wants 5.5 to 7.5, and this soil is in that range. The free drainage is exactly what it wants. Sandy soil is among the soils it is recorded as suiting.
Chalky and alkaline	Grows well here	Lemon balm grows perfectly well on chalky and alkaline without special measures, though it is not the soil it would choose.
Loam	Prefers this soil	Loam suits Lemon balm as it stands: The pH suits it: it wants 5.5 to 7.5, and this soil is in that range. The free drainage is exactly what it wants. Loam is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering.
Silty	Prefers this soil	Silty suits Lemon balm as it stands: The pH suits it: it wants 5.5 to 7.5, and this soil is in that range. The free drainage is exactly what it wants. The soil holds moisture, which saves a great deal of watering.
Peaty and acid	Works, with one condition	Lemon balm will crop on peaty and acid, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. A plant that stays in the ground through winter with its roots in cold, saturated soil rots — which is what kills most of what fails on heavy ground, rather than the cold.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse.
Shallow over rock	Prefers this soil	Shallow over rock suits Lemon balm as it stands: The free drainage is exactly what it wants. Loam is among the soils it is recorded as suiting.
Made ground and urban soil	Works, with one condition	Lemon balm will crop on made ground and urban soil, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. A plant that stays in the ground through winter with its roots in cold, saturated soil rots — which is what kills most of what fails on heavy ground, rather than the cold.Improve the drainage before planting — a raised bed, or bulky organic matter worked in over several seasons. Do not add sand to clay in small quantities; it makes the problem worse.

Not sure which you have? Four hand tests will settle it.

Space and spacing

Mature height: 60–90 cm
Mature spread: 45–60 cm
Rooting depth: 30 cm
Spacing: 45–60 cm apart

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
SpacingSourced guidancemoderate confidence: Royal Horticultural Society: Lemon balm — spacing
Checked 2026-08-13

Measured centre to centre. Plants set closer than this compete for light and water long before they look crowded, and the crowding cannot be undone once they are in.

In a container

Minimum volume: 7 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

Grow it in a pot on purpose rather than as a compromise — lemon balm seeds itself hard enough to become a nuisance in a border, and a container keeps it where it was put. Cut it back before the flowers set seed.

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
Open ground	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Traditional dug bed	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Raised bed	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Container	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13	7 litres; Chosen for containment as much as for space
Greenhouse	Well suited source Sourced guidancemoderate confidence Agriculture and Horticulture Development Board — AHDB: Herbs under protection Checked 2026-08-13
Polytunnel	Well suited source Sourced guidancemoderate confidence Agriculture and Horticulture Development Board — AHDB: Herbs under protection Checked 2026-08-13
Windowsill	Workable source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Hydroponics	Workable source GrowingHQ editorial positionmoderate confidence Vigorous, soft-leaved and entirely happy in a system — and it will fill the channel and shade its neighbours within weeks. GrowingHQ editorial synthesis — GrowingHQ Checked 2026-08-13

Growing it

PruningCut the whole plant back hard before the flowers open — around midsummer. It prevents self-seeding, which is the plant's only real fault, and produces a flush of fresh leaves for late-season picking.
HarvestingPick leaves before flowering. The lemon oil is strongest then and drops away noticeably once the plant flowers.
PropagationDivide an established clump in spring or autumn — it is a mint relative and comes apart just as willingly, with roots on every piece. It also seeds itself very freely indeed, which is worth knowing before deciding you need more: cutting the plant back before it flowers is usually the more useful operation.
WateringUndemanding, but it wilts dramatically in a dry spell and the leaves brown at the edges. Water established clumps only in prolonged drought; water pots whenever the compost surface has dried, because a pot-grown lemon balm that dries repeatedly gets tough leaves and mildew. It recovers from wilting readily, which is more than most herbs manage.
FeedingNone in the ground — lemon balm is vigorous enough already, and feeding simply makes a bigger plant to cut back. A container plant benefits from fresh compost each spring rather than fertiliser.
PlantingPlant in spring in sun or part shade — and think about where, because this is a plant that seeds itself hard. A pot, a gap in paving or a corner where seedlings can be hoed off is a better home than the middle of a mixed border. Cut it back before the flowers set seed and it stays where it was put.

Where this guidance comes from

PruningSourced guidancehigh confidence: Royal Horticultural Society: Lemon balm — care
Checked 2026-08-13
HarvestingSourced guidancehigh confidence: Royal Horticultural Society: Lemon balm — harvesting
Checked 2026-08-13
PropagationSourced guidancemoderate confidence: Royal Horticultural Society: Lemon balm — cultivation
Checked 2026-08-13
WateringSourced guidancehigh confidence: Royal Horticultural Society: Lemon balm — cultivation
Checked 2026-08-13
FeedingSourced guidancehigh confidence: Royal Horticultural Society: Lemon balm — cultivation
Checked 2026-08-13
PlantingSourced guidancehigh confidence: Royal Horticultural Society: Lemon balm — cultivation
Checked 2026-08-13

The bud you cut to becomes the new shoot, and it grows in the direction it points — which is why an outward-facing bud opens the plant up and an inward-facing one crosses the middle.

The rule is the same in all four: the new piece needs both a growing point and roots of its own. A cutting is the exception that has to make its roots afterwards, which is why the node matters so much.

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	No real benefit source GrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file. GrowingHQ editorial synthesis — GrowingHQ Checked 2026-08-13	Nothing, and it seeds itself freely — which under cover means it appears in every pot on the bench for years.
Polytunnel	No real benefit source GrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file. GrowingHQ editorial synthesis — GrowingHQ Checked 2026-08-13	Nothing, and it seeds itself freely.

On a windowsill

Spring to autumn

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

Productive from roughly March to October and not after. Growth stops when the light does, and a plant pushed through the dark months usually does not recover. Dormancy and vigour. Herbaceous and hardy, so it wants the same winter rest as mint, and it fills a pot in a season.

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.

Works with conditions

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

Vigorous, soft-leaved and entirely happy in a system — and it will fill the channel and shade its neighbours within weeks.

GrowingHQ editorial synthesis — GrowingHQ

Checked 2026-08-13

Techniques that suit it

Nutrient film (NFT)A shallow stream of solution runs over bare roots in a sloped channel. Cheap and productive for small fast crops; a pump failure kills a crop within hours because there is no reservoir at the roots.
Deep water cultureRoots hang in aerated solution. Very productive and very unforgiving of solution temperature — warm solution holds less oxygen and root disease follows.
Ebb and flowA bed of inert medium floods and drains on a timer. The medium holds moisture between floods, which makes it far more tolerant of interruption than NFT.

source

Horticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Root space: Small, but the top growth is not.
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 readyLeaves are at their most fragrant on young growth before the plant flowers in midsummer; after flowering they coarsen and the scent fades. Cutting the whole plant back hard in July produces a second flush of good young leaves and prevents it seeding.
How to pick itCut whole stems back to a low pair of leaves. It dries acceptably but loses much of its scent; fresh leaves make a far better tea.

Where the harvest guidance comes from

When it is readySourced guidancehigh confidence: Royal Horticultural Society: Lemon balm — 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
Powdery mildew	occasional source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13

Sources for this page

Agriculture and Horticulture Development Board · 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.