How to Grow Borage UK

When to Plant Borage in the UK

When to plant borage in the UK: in Southern England, sow early April to mid May. Find your area in the table below.

Region	Sow
Southern England	early April to mid May
Midlands	early April to mid May
Northern England	early April to mid May
Scotland	early April to mid May

Southern England - detail & sources

RHS: sow in April under cover at 15°C, or direct sow outdoors in spring once conditions allow, through to early May. A single window is applied uniformly across all four sub-regions since the source gives no UK-region-specific gradient; borage is H5-hardy and self-seeds readily throughout the UK.

Midlands - detail & sources

RHS: sow in April under cover at 15°C, or direct sow outdoors in spring once conditions allow, through to early May. A single window is applied uniformly across all four sub-regions since the source gives no UK-region-specific gradient; borage is H5-hardy and self-seeds readily throughout the UK.

Northern England - detail & sources

RHS: sow in April under cover at 15°C, or direct sow outdoors in spring once conditions allow, through to early May. A single window is applied uniformly across all four sub-regions since the source gives no UK-region-specific gradient; borage is H5-hardy and self-seeds readily throughout the UK.

Scotland - detail & sources

RHS: sow in April under cover at 15°C, or direct sow outdoors in spring once conditions allow, through to early May. A single window is applied uniformly across all four sub-regions since the source gives no UK-region-specific gradient; borage is H5-hardy and self-seeds readily throughout the UK.

Quick Facts

Factor	Value
Drainage	well-drained; tolerates chalk, clay, loam, and sand

At a Glance

Soil & Growing Conditions

Water: does best in dry, sunny places once established; tolerates poor/dry soil

Growth Stages

Stage	BBCH	Notes
Sowing and germination	0	Sow in April in seed trays or pots at about 15°C, or direct sow outdoors in spring; germination takes roughly five to ten days (RHS).
Establishment and spacing	1	Space plants about 50cm apart in full sun or light shade, on any soil that is not waterlogged (RHS).
Vegetative growth	3	Plants grow into an erect habit 50-70cm tall; keep soil moist through summer for the biggest, best plants (RHS).
Flowering and harvest	6	Flowers appear about 10-12 weeks after a spring sowing; pick individual blooms just as they open. Watch for powdery mildew later in summer once peak flowering is over (RHS).

Harvest & Storage

When to pick: Pick blossoms as they open; use leaves fresh, picking young/tender leaves for best flavour (they are seldom dried). Successive sowings at 4-week intervals extend the harvest.

Diseases

Powdery mildew

RHS: "May be susceptible to powdery mildews."

Pests

Slugs

Gastropoda (slugs, various spp.)

RHS: "Foliage may be damaged by slugs and leaf-mining flies."

Companion Planting

Strawberry

beneficial

Fragaria x ananassa

Pollinator attraction

Borage, the Bee-Magnet Herb with Starry Blue Flowers

Starry blue flowers

Bright blue, star-shaped flowers about 2cm across appear over a long period through summer.

Buds open in succession

Hairy, nodding buds open in succession, keeping the plant in flower for weeks on end.

An erect annual herb

RHS: borage forms an erect plant 50-70cm tall, thriving in full sun on any soil that is not waterlogged.

Cucumber-scented leaves

The broad, bristly leaves carry a distinct cucumber scent and are picked young for salads.

Coarsely hairy throughout

Stems and foliage are covered in coarse white hairs, a hallmark of the borage family.

What the research guides add

Borage is an easy annual that comes back by itself.

• An annual from the Mediterranean with bright blue star-shaped flowers; it grows best in full sun but is not adversely affected by light shade, and does well in all types of soil, including poor soil. (NC State Extension)
• Grow it from seed; it is self-seeding and will remain in the garden year after year. (NC State Extension)
• The stems and tender leaves are edible and taste and smell like cucumber, although the leaves lose their flavour when dried. (NC State Extension)
• Cut the plant back by half in mid-summer for new growth in the fall. (NC State Extension)

Sources for this section

• NC State Extension: Borago officinalis (Plant Toolbox)

Section researched and checked on 25 October 2026 by the SoilCommander Editorial Team. How we check facts: editorial policy.

References

1. Ecological Entomology (Wiley) -- Griffiths-Lee, Nicholls & Goulson, 2020 - Companion planting to attract pollinators increases the yield and quality of strawberry fruit in gardens and allotments

   Peer-reviewed; abstract fetched directly by research subagent from University of Sussex repository. Researcher-led trial + UK-wide citizen-science replication.

2. GBIF - GBIF Backbone Taxonomy match: Borago officinalis (family/genus/species)
3. NC State Extension - Borago officinalis (Borage)

   Annual reaching about 1ft 7in-3ft 2in tall and 1ft-1ft 4in wide; fits a space under 12in across. Full sun or partial shade. Tolerates clay, loam and sand at acid, neutral or alkaline pH, but needs good drainage and copes with occasional dryness. Grown from seed and self-seeds freely, so it returns year after year once introduced. Strongly attractive to bees and other wildlife. Flowers are used as edible flowers and young leaves in salads, teas and sandwiches, tasting and smelling of cucumber; dried leaves lose the flavour. CAUTION: borage contains liver-damaging pyrrolizidine alkaloids and should be eaten only sparingly; it is hazardous to cats, dogs and horses, and only certified PA-free borage seed oil should be used. Few problems; powdery mildew can occur.

4. Royal Horticultural Society - Borago officinalis | borage
5. Royal Horticultural Society - How to grow borage

   Sow in seed trays and pots in April at 15°C, or direct sow in spring. Space plants about 50cm apart. Thrives in full sun but tolerates light shade; grows on any soil that is not waterlogged, preferring moist soil in summer for the biggest plants. Annual borage reaches 50-70cm tall with an erect habit. Self-seeds readily; seedlings germinating later in summer usually flower but stay shorter. Can get powdery mildew later in summer, after peak flowering.

6. University of Maryland Extension - Borage
7. University of Minnesota Extension - Berries, bees, and borage

   2016-2018 field trials.

7 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.