GrowingHQ
Herbculinary herbStraightforward

Borage

Borago officinalis

Grown for its flowers rather than in spite of them, which makes it the exception in a herb bed. Borage is coarse, seeds itself everywhere and is among the best bee plants that will grow in a British garden — the honest reason to plant it is the insects, and the cucumber-flavoured flowers are a bonus.

Position
Full sun or Partial shade
Water
low demand
Drainage
Free-draining
Grows to
60–100 cm × 45–60 cm
Hardiness
H3
Harvest
June to September
Difficulty
Straightforward

Described view

Borage in full flower with the blue star-shaped blooms and visible bees working them

August

In flower · Harvest

Borage’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.

ActivityJFMAMJJASOND
Sow outdoorsApril. May. June.
In flowerJune. July. August. September.
HarvestJune. July. August. 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.

Mediterranean woody herb

Growing regime
source

Sourced guidancehigh confidence

  • Royal Horticultural Society: Borage — growing

Checked 2026-08-13

Wants sun, poor free-draining ground and very little water once established. Far more of these die from winter wet at the roots than from cold air, so drainage matters more than hardiness ratings suggest.

Treated the same way: bay, chamomile, hyssop, lemon thyme, marjoram, oregano and 7 more in the same group. The herb bed, split by regime

Why winter wet kills a Mediterranean herbTwo soil cross-sections side by side. On the left, a well-drained planting: the crown of a rosemary sits slightly proud of the surrounding soil on a low mound, the root zone is open gritty soil with air between the particles, and arrows show winter rain moving down and away past the roots. The plant above is dense and well furnished. On the right, the same herb in heavy soil in a hollow: the crown sits level with or below the surface, the root zone is dense soil over a compacted pan, and winter rain has nowhere to go so a water table stands in the root zone from November to March. The roots there are drawn broken and dashed to show they have died, and the plant above is sparse and thin. The point is that the plant looks unharmed all winter because an evergreen with a full canopy asks almost nothing of its roots in January, so the loss only shows the following spring when it fails to grow.Sharp drainagecrown proud, water moves throughroots stay firm and paleair between the particles all winterWinter wetcrown in a hollow, water standswater table, Nov–Marcompacted pan — nowhere to goroots dark, soft and sourand the plant above still looks fineopen gritty soilheavy soilstanding waterliving rootsPlanting on a low mound, adding grit, or standing a pot on feet all do the same job: get the crown above the water.
The damage happens in January and shows in May. An evergreen herb asks almost nothing of its roots in winter, so a drowned root system stays invisible until the plant is asked to grow and cannot.
Indoors
Not worth growing indoors
Where the indoor assessment comes from
IndoorsSourced guidancemoderate confidence
  • Royal Horticultural Society: Borage — 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.

Flowering is part of the point
source

Sourced guidancehigh confidence

  • Royal Horticultural Society: Borage — harvesting

Checked 2026-08-13

Nothing to do about it. Flowering does not change what borage is worth picking, so there is no reason to prevent it.

What it is worth to pollinators

Recorded only where the evidence is specific to this plant, because “good for bees” attached to everything means nothing attached to anything.

Nectar value
high
source

Sourced guidancehigh confidence

  • Royal Horticultural Society: Plants for pollinators

Checked 2026-08-13

Pollen value
high
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Plants for pollinators

Checked 2026-08-13

In flower
June, July, August, September

Conditions it needs

Light
Full sun, Partial shade
Frost
Half hardy
Hardiness rating
H3 (RHS)
Grows best at
12–25 °C
Soil
Sandy, Loam, Chalky
Soil pH
6–7.5
Drainage
Free-draining
Water needs
low
Drought
good tolerance
Waterlogging
poor tolerance
Heat
good tolerance
Wind and exposure
moderate tolerance
Where these figures come from
LightSourced guidancemoderate confidence
  • Royal Horticultural Society: Borage — position

Checked 2026-08-13

FrostSourced guidancehigh confidence
  • Royal Horticultural Society: Borage — 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: Borage — temperature

Checked 2026-08-13

SoilSourced guidancemoderate confidence
  • Royal Horticultural Society: Borage — soil

Checked 2026-08-13

Soil pHSourced guidancemoderate confidence
  • Plant Finder — Missouri Botanical Garden: Borago officinalis — culture

Checked 2026-08-13

DrainageSourced guidancemoderate confidence
  • Royal Horticultural Society: Borage — 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

Tall and brittle; it flops badly in an open site.

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.

SoilVerdictWhy
Heavy clayWorks, with one conditionBorage will crop on heavy clay, but one thing has to be dealt with first. It needs ground that drains, and this soil holds water. For a crop lifted before winter the risk is not rot but the season: waterlogged ground is cold and unworkable in spring, so sowing is late and germination patchy.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.
SandyPrefers this soilSandy suits Borage as it stands: The pH suits it: it wants 6 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. It stands dry conditions better than most, which this soil will test.
Chalky and alkalinePrefers this soilChalky and alkaline suits Borage as it stands: The free drainage is exactly what it wants. Chalky soil is among the soils it is recorded as suiting. It stands dry conditions better than most, which this soil will test.
LoamPrefers this soilLoam suits Borage as it stands: The pH suits it: it wants 6 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.
SiltyPrefers this soilSilty suits Borage as it stands: The pH suits it: it wants 6 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 acidWorks, with one conditionBorage 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. For a crop lifted before winter the risk is not rot but the season: waterlogged ground is cold and unworkable in spring, so sowing is late and germination patchy.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 rockPrefers this soilShallow over rock suits Borage as it stands: The free drainage is exactly what it wants. Loam is among the soils it is recorded as suiting. It stands dry conditions better than most, which this soil will test.
Made ground and urban soilWorks, with one conditionBorage 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. For a crop lifted before winter the risk is not rot but the season: waterlogged ground is cold and unworkable in spring, so sowing is late and germination patchy.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
60–100 cm
Mature spread
45–60 cm
Rooting depth
40 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: Borage — spacing

Checked 2026-08-13

How far apart to plant borageThree borage plants drawn in a row at their recorded spacing of 45–60 cm between plants. The spacing is drawn to scale against a one metre rule; the plants themselves are symbols rather than scale drawings, so the distance between them is the part to read.45–60 cmone metre
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
10 litres or more
Minimum depth
30 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

Needs a deep container for its taproot and will still be shorter than a plant in the ground. Self-seeds enthusiastically into every pot nearby.

Value to wildlife

Recorded only where the evidence names a resource and the months it is available. Most plants flower; that on its own is not what this section is about.

Nectar
A significant source
Pollen
A significant source
In flower
Jun, Jul, Aug, Sep
Where these figures come from
NectarSourced guidancehigh confidence
  • Royal Horticultural Society: Plants for pollinators

Checked 2026-08-13

PollenSourced guidancemoderate confidence
  • Royal Horticultural Society: Plants for pollinators

Checked 2026-08-13

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.

MethodSuitabilityWhat it needs
Open groundWell suited
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Growing method suitability

Checked 2026-08-13

Traditional dug bedWell suited
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Growing method suitability

Checked 2026-08-13

Raised bedWorkable
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Growing method suitability

Checked 2026-08-13

ContainerWorkable
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Growing method suitability

Checked 2026-08-13

10 litres; Support in an exposed spot
GreenhouseWorkable
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Growing method suitability

Checked 2026-08-13

PolytunnelWorkable
source

Sourced guidancemoderate confidence

  • Royal Horticultural Society: Growing method suitability

Checked 2026-08-13

HydroponicsMarginal
source

GrowingHQ editorial positionmoderate confidence

Sixty centimetres of bristly plant grown for flowers that exist to be worked by bees. Everything about it argues against an indoor system.

  • GrowingHQ editorial synthesis — GrowingHQ

Checked 2026-08-13

WindowsillMarginal
source

Horticultural consensusmoderate confidence

  • Royal Horticultural Society: Growing herbs and salads indoors

Checked 2026-08-13

Growing it

  • ProtectionDeadhead before the seed drops if you do not want it everywhere next year. A single plant left to finish will seed a whole bed, and borage seedlings have a taproot that makes them awkward to remove once established.
  • PropagationSow direct rather than raising plants to transplant. Borage makes a taproot early and resents disturbance, so a module-raised plant checks badly and often flowers small.
  • WateringWater young plants until they are established and then leave them alone — borage is deep-rooted and drought-tolerant, and a plant kept wet grows enormous, falls over and mildews. In a container it needs more attention, because the taproot has nowhere to go.
  • FeedingNone needed on any reasonable soil. Borage grown hard produces more flower and stands up better; on rich ground it makes a large soft plant that needs staking and self-seeds even more freely than usual.
  • HarvestingPick the flowers, which is the point of the plant: take them as they open, pulling the star of petals away from the black centre and leaving the hairy sepals behind. Young leaves can be picked for their cucumber flavour but the bristles make older ones unpleasant, so take only the small ones near the growing tip. Flowers do not keep — pick them the same day they are wanted, or freeze them in ice cubes.
  • SowingSow direct where it is to flower, from April to June, at about 2 cm deep and thinned to 30 cm. Borage has a taproot and resents transplanting, and it grows so fast from seed that raising it in modules gains nothing. Sow once and it will seed itself thereafter, generously enough that most gardens never sow it again.
Where this guidance comes from
ProtectionSourced guidancehigh confidence
  • Royal Horticultural Society: Borage — growing

Checked 2026-08-13

PropagationSourced guidancemoderate confidence
  • Royal Horticultural Society: Borage — sowing

Checked 2026-08-13

WateringSourced guidancemoderate confidence
  • Royal Horticultural Society: Borage — cultivation

Checked 2026-08-13

FeedingSourced guidancemoderate confidence
  • Royal Horticultural Society: Borage — cultivation

Checked 2026-08-13

HarvestingSourced guidancehigh confidence
  • Royal Horticultural Society: Borage — harvesting

Checked 2026-08-13

SowingSourced guidancehigh confidence
  • Royal Horticultural Society: Borage — sowing

Checked 2026-08-13

Four ways to make more plantsFour propagation operations compared, each showing where the separation is made and what must be present on both sides of it. Division: a clump cut between crowns, with roots and at least one growing point on every piece. Stem cutting: a shoot cut just below a leaf node, because the node is where roots form, with the lower leaves removed. Runner: a plantlet already rooting where it touches the ground, severed from the parent only after its own roots have taken. Offset: a young shoot at the base of the parent, separated with its own roots attached. In each case the cut is marked and the part that must be retained is labelled.Divisioncut between crownsroots on every piececut below a nodeStem cuttingroots form at the nodestrip the lower leavesRunnerlet it root firstthen sever the linkOffseta shoot at the basetake its roots with it
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.

On a windowsill

Does not work indoors
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

 Not a windowsill crop. The reason is given — usually light, root volume or sheer size. Size and pollination. Borage reaches 60 cm across, has bristly leaves that hate confinement, and is grown for flowers that exist to be worked by bees.

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.

Not worth it

It can be made to grow, but a soilless system is the wrong tool — usually because of rooting volume, running cost, or a result no better than a pot of compost.

source

GrowingHQ editorial positionmoderate confidence

Sixty centimetres of bristly plant grown for flowers that exist to be worked by bees. Everything about it argues against an indoor system.

  • GrowingHQ editorial synthesis — GrowingHQ

Checked 2026-08-13

Included because it appears in beginner herb kits, where nothing about it belongs.

Techniques that suit it

  • 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.
Horticultural consensusDepends on conditionsmoderate confidence

Applies when: Physically possible; the plant's purpose is not.

No external citation — see the evidence type above.

Checked 2026-08-13

Root space
Large, with a taproot.
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

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

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 readyFlowers are ready as they open and should be picked the same day they are wanted — they wilt within hours. Leaves are worth picking only while small and near the growing tip; older ones are covered in stiff bristles that make them unpleasant raw.
  • How to pick itPull the star of petals away from the black centre, leaving the hairy sepals on the plant. Freeze flowers in ice cubes if they are wanted later; they do not dry.
Where the harvest guidance comes from
When it is readySourced guidancehigh confidence
  • Royal Horticultural Society: Borage — 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

ProblemHow oftenNotes
Normal end of an annual's lifecommon
source

Horticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Collapsing in August is the plant finishing, not failing.
Powdery mildewcommon
source

Horticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Aphidsoccasional
source

Horticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Foliage that is meant to look like thatcommon
source

Horticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

Young leaves unfold deeply puckered under stiff white bristles and flatten as they expand.

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 2026-08-15.