Licensed field crop

How to grow hemp

Cannabis sativa

You cannot legally grow hemp in a UK garden, allotment or pot. Hemp is Cannabis sativa, and growing it without a Home Office licence is an offence however little THC the plant contains. Licences are issued for outdoor field crops of approved low-THC varieties grown for fibre or seed. Licensed growers drill it in late April or May into a firm, well-drained seedbed, feed it before sowing, then mow for fibre in August or combine for seed in August to September.

Hardiness
Annual, sown each spring once hard frosts are over; established seedlings stand a light frost
Position
Full sun in an open field, on a site covered by a Home Office licence; not a garden plant
Soil
Deep, well-drained, humus-rich loam; not wet or compacted clay
Ideal pH
6.0 to 7.5
Water
Moderate: about 300 to 400 mm over the season, half of it at flowering and seed set; seedlings will not stand waterlogging
Feeding
Moderate feeder

Sowing and planting hemp

WhenLicence first; drill late Apr to May; mow fibre crops Aug; combine seed crops Aug to Sep

Starting off

Only with a Home Office licence already issued. Buy certified seed of an approved low-THC variety from an official supplier and keep the invoice. Prepare a fine, firm seedbed as for spring barley and drill direct from late April, when hard frosts are over and the soil is at 8 to 10 °C. It is not raised in pots or transplanted.

Spacing and planting

Drilled, not planted: rows 15 to 18 cm apart, seed 2 to 3 cm deep. Fibre crops are sown thickly, about 180 seeds per square metre for 115 to 130 plants per square metre, which keeps stems thin. Seed crops are sown thinner, about 2.5 g of seed per square metre (25 kg/ha). Fibre varieties reach 3 m; short seed varieties such as Finola about 1.5 m.

Varieties worth growing

Finola
Short seed variety reaching about 1.5 m, grown mainly for seed and oil and easier to combine than the tall fibre types.
Futura 75
Tall French variety grown mainly for fibre; the stem length is the crop, so it suits growers with a fibre processor within reach.
Felina 32
French variety used as a dual-purpose crop, taking seed with the combine and baling the straw afterwards.
USO 31
Early variety grown for seed and straw, a choice where a late harvest would run into autumn weather.

Hemp month by month

Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.

  1. January

    Nothing to sow. If you intend to grow, read the current Home Office industrial hemp guidance and check the application window.

  2. February

    Apply for the licence online in good time. Order certified seed of an approved variety and keep the invoice. Test soil pH.

  3. March

    Lime only if the pH test shows the soil is below 6.0. Loosen compaction. Do not sow: nothing goes in the ground until the licence is issued.

  4. April

    Prepare a fine, firm seedbed and rake in the base dressing. Licence in hand, drill from late April once hard frosts are over.

  5. May

    Main sowing month. Tell the local police where the crop is, as the licence guidance requires. Keep off wet ground.

  6. June

    Top-dress when the crop is 20 to 30 cm tall and water it in. The canopy closes this month and takes over the weeding.

  7. July

    Nothing to do in the crop. Fibre varieties reach full height. Book the mower, baler or combine.

  8. August

    Mow fibre crops at early flowering and leave the swath to ret. Early seed varieties may be ready to combine at the end of the month.

  9. September

    Combine seed crops when about 70% of the seed is ripe and dry the seed at once. Turn, then bale retted straw when dry.

  10. October

    Store bales under cover. Deal with leaves and flower material on the licensed site as the licence requires. Write up yield records.

  11. November

    Nothing to do in the field. Plan next year's ground: a different field from this year's.

  12. December

    Nothing to do. Licences expire on 31 December of their final season; check yours and the date for the annual review statement.

Feeding hemp

A fast-growing crop that takes most of its feed in the first two months, so nearly all of it goes on before drilling. Published guides put the need at roughly 6 to 12 g of nitrogen per square metre with moderate phosphate and potash; too much nitrogen with too little potash gives stems that snap.

NNitrogenModerate
PPhosphorusModerate
KPotassiumModerate

Fast growing, so the feed goes on before drilling: a balanced base dressing raked into the seedbed and one light top-dress when the crop is 20 to 30 cm tall. Keep nitrogen and potash in balance, because lush growth short of potash snaps in summer storms.

Feeding plan

WhenWhatHow much

Late winter, only if a pH test reads below 6.0

Garden Lime (calcium carbonate)

About 0.5 kg/m², the label rate for a typical bed, spread evenly and worked in. Hemp does best at pH 6.0 to 7.5; if the test is already in that range, apply none.

April, a week or two before drilling

Fruit & Vegetable Fertiliser 4-5-6

100 g/m², inside the label's 70 to 110 g/m², raked into the top few centimetres of the seedbed. That supplies 4 g nitrogen, 5 g phosphate and 6 g potash per square metre (100 g × 4%, 5% and 6%).

Late May to June, crop 20 to 30 cm tall

Fruit & Vegetable Fertiliser 4-5-6

50 g/m², the bottom of the label's 50 to 100 g/m², scattered evenly and watered in. Season total 100 + 50 = 150 g/m², which is the label maximum, so nothing more after this. Total supplied: 6 g nitrogen, 7.5 g phosphate and 9 g potash per square metre.

Hemp can only be grown in the UK under a Home Office licence. The feeding plan is written for a small licensed plot and uses one dry fertiliser at label rates.

Signs to watch

What you seeCauseWhat to do

Pale, thin, short plants in June

Nitrogen short on a fast-growing crop

Top-dress and water in

Tall stems leaning or snapping after a summer storm

Too much nitrogen for the potash available

Hold nitrogen to the plan and use a balanced feed

Seedlings yellow and stalled in the first three weeks

Waterlogged or compacted soil

Choose free-draining ground and never drill into a wet seedbed

Pests, diseases and problems

What you seeCauseWhat to do

Weeds overtaking the crop in its first month, worst in thinly sown seed crops

An open canopy; hemp only smothers weeds once a dense stand has closed over the ground

Make a stale seedbed: prepare the ground, let the first flush of weeds germinate and hoe it off before drilling. Sow into warm soil so the crop gets away fast, and do not drop the seed rate below what the supplier advises.

Seedlings yellow and stalled in the first three weeks

Waterlogged or compacted soil; young hemp is very sensitive to wet feet until it is about 30 cm tall

Choose free-draining ground, loosen any compaction before drilling and never drill into a wet seedbed.

Stems rotting with white cottony mould, plants wilting in patches

Sclerotinia (white mould), which carries over in the soil from other host crops

Keep hemp to one year in four on the same ground and do not follow oilseed rape, beans or sunflowers. Control in the growing crop is seldom worthwhile.

Grey furry mould on stems and seed heads in a wet late summer

Botrytis (grey mould)

Harvest on time rather than leaving a ripe crop standing in wet weather; avoid excess nitrogen, which gives soft, crowded growth.

Small round shot holes in seedling leaves

Flea beetle

Usually nothing: the crop grows through it. A fine, firm, moist seedbed that gives fast even emergence is the defence.

Ripening seed heads stripped, seed on the ground

Birds, which can take a large share of a seed crop, and seed shedding from an over-ripe crop

Combine as soon as about 70% of the seed is ripe rather than waiting for the whole head; later harvests lose more to birds and shattering.

Harvest and rotation

Harvest and storage

Fibre crops are mown in August at early flowering, before seed sets, left in the swath for three to four weeks to ret, turned, then baled dry and stored under cover. Seed crops are combined in August to September when about 70% of the seed is ripe, and the seed is dried straight away to below 10% moisture for storage. Only the seed and the mature stalk may be used: leaves and flowers must be retted on the licensed site or otherwise lawfully disposed of.

Rotation and companions

Rotation: a spring-sown break crop grown one year in four, deep rooted and weed suppressing, which leaves good structure for the crop that follows. Do not sow it after oilseed rape, beans or sunflowers, which share sclerotinia. It is grown as a solid stand, with no companions.

Good to knowHemp is Cannabis sativa and it is illegal to grow in the UK without a Home Office licence, whatever its THC content, so it cannot be grown in a garden, allotment or pot.

Growing hemp in pots

Hemp is not a pot plant or a garden plant in the UK, and this page does not tell you how to grow it as one. It is Cannabis sativa, and growing even one plant without a Home Office licence is an offence, whatever its THC content. Licences are issued for outdoor field cultivation, for a commercial fibre or seed use, to a named grower at a named site, so a pot, greenhouse, garden bed or allotment cannot be covered. It would make a poor container plant in any case: a densely drilled, tap-rooted field crop that stands 1.5 to 3 m tall. If you want a tall, fast annual in a tub, grow sunflowers or sweetcorn.

Hemp: common questions

Is it legal to grow hemp in the UK?

Not without a Home Office licence. Hemp is Cannabis sativa, a controlled drug under the Misuse of Drugs Act 1971, and cultivating it without a licence is an offence even when it is a low-THC industrial variety. Licences cover outdoor crops of approved varieties with no more than 0.2% THC, grown for fibre or seed only. They are issued to a named grower for a named site, so a garden or allotment plant is not covered. Check the current Home Office guidance on GOV.UK before doing anything.

How much does a hemp growing licence cost in the UK?

The Home Office factsheet, last updated in December 2025, gives £580 for a new low-THC licence and £326 for a renewal, with a further charge if a compliance visit is needed. From the 2026 season a licence typically runs for up to six growing seasons and expires on 31 December. Each named person also needs an enhanced DBS check, and the guidance says to apply at least 4 to 6 weeks before sowing. Fees and terms change, so check the current Home Office guidance.

Is hemp a good break crop for the soil?

Yes, for licensed growers it is a useful spring break crop. It is deep rooted, needs few inputs, closes its canopy fast enough to suppress weeds, and returns a large share of its growth to the ground as leaf, root and tops, so the crop that follows often does better. Keep it to one year in four on the same field and avoid following oilseed rape, beans or sunflowers, which share sclerotinia with it.

Sources

Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.