Perennial
How to grow asparagus
Asparagus officinalis
Asparagus is planted once and cropped for 15 years or more, so the bed matters more than anything you do afterwards. Plant one-year-old crowns in March or April in full sun, in soil that drains freely and has been cleared of every perennial weed. Do not cut any spears for the first two years. From the third spring, cut from late April to mid June, then let the ferns grow to rebuild the crowns. Asparagus is a moderate feeder, and the feeding plan below sets out the best fertiliser for asparagus and when to give it.
- Hardiness
- Fully hardy
- Position
- Full sun
- Soil
- Free-draining, weed-free; raised beds suit it
- Ideal pH
- 6.5 to 7.5
- Water
- Moderate, only in dry spells while ferns grow
- Feeding
- Moderate feeder
Sowing and planting asparagus
WhenPlant crowns Mar to Apr; harvest late Apr to mid Jun from year three
Starting off
Plant one-year-old bare-root crowns in March to April as soon as they arrive, never letting the roots dry; all-male F1 'Gijnlim', 'Backlim' or 'Pacific 2000' give no seedlings and bigger spears. Seed is sown 2 cm deep in modules at 15 to 20 °C in February to March, germinating in 14 to 21 days, and planted out the following spring, which adds a year to the wait.
Spacing and planting
Plant crowns 30 to 45 cm apart in rows 45 cm apart, in a trench 20 cm deep and 30 cm wide with a 10 cm ridge of soil along the bottom; spread the roots over the ridge, cover with 5 cm of soil and fill in as shoots grow. Not a container plant.
Varieties worth growing
- Gijnlim F1
- All-male hybrid and the earliest to crop, often by a fortnight; heavy yields of medium spears. The safe first choice.
- Backlim F1
- All-male, later than Gijnlim with thicker spears; plant both to stretch the season at each end.
- Guelph Millennium
- Late to emerge, so it dodges spring frost; a good choice for colder gardens and heavier soils.
- Pacific Purple
- Purple spears that are sweeter and less stringy than green types, tender enough to eat raw. The colour fades to green when cooked.
- Connover's Colossal
- The old open-pollinated variety, cheap to raise from seed. It produces male and female plants, so expect berries, seedlings and a slightly lower yield.
Asparagus month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Order crowns. Dig out perennial weeds from the site of a new bed.
- February
Mulch established beds with 5 cm of garden compost. Test the soil pH.
- March
Feed established beds. Plant crowns from mid month as soon as they arrive.
- April
Plant crowns. First spears late in the month; cut only from beds in their third year or older. Fleece on frosty nights.
- May
Cut every 2 to 3 days at 15 to 18 cm. Hand weed. Start checking for asparagus beetle.
- June
Stop cutting by mid June. Feed straight after the last cut and let every spear grow into fern.
- July
Support the ferns with canes and string. Water new beds in dry spells. Keep picking off beetles.
- August
Hand weed; do not hoe deeply over the crowns. Pull out any seedlings near berry-bearing plants.
- September
Nothing to do except weeding. Leave the ferns alone while they are green.
- October
Cut the ferns down to 5 cm above the soil once they have turned yellow.
- November
Finish cutting down. Clear the debris off the bed and burn or bin it.
- December
Nothing to do.
Feeding asparagus
A moderate feeder with two feeding moments: early spring before the spears, and mid June after the last cut, when the ferns are building next year's crop. The June feed is the one that matters.
On a permanent bed, feed in spring as spears emerge and again once cutting stops; it values potassium and phosphorus.
Feeding plan
At planting, once
The label rate is 5 g per litre of root-ball volume. A one-year crown's roots fill roughly a litre, so dust about 5 g (a level teaspoon) directly onto the roots of each crown as you spread them over the ridge.
February, every year
Garden compost
A 5 cm mulch over the whole bed. It feeds, holds moisture and keeps weeds down so you never need to dig near the crowns.
Early March, before the spears show
Fruit & Vegetable Fertiliser 4-5-6
70 g/m² scattered over the bed and lightly raked in. With rows 45 cm apart that is about 32 g per metre of row.
Mid June, straight after the last cut
Fruit & Vegetable Fertiliser 4-5-6
50 to 80 g/m², which is 22 to 36 g per metre of row, watered in. With the March dose this stays at or under the label limit of 150 g/m² a season.
Mid June, only where spears have been thin
20 g/m², about 9 g per metre of row, with the June feed.
Late winter, only if a test shows pH below 6.5
Garden Lime (calcium carbonate)
About 0.5 kg/m² scattered over the bed and left for rain to wash in. Retest the following year before repeating.
Signs to watch
Thin, pencil-width spears in an established bed
Crowns exhausted by over-cutting or potassium short
Stop cutting by mid June and feed potash after the last cut
Yellowing ferns in August
Waterlogging or nitrogen short on light soil
Improve drainage and feed in spring
Crooked, bent spears
Wind or insect damage, not nutrition
Cut regularly and shelter
Pests, diseases and problems
Black and cream beetles with a red thorax and grey, slug-like grubs on the spears and ferns from May; ferns stripped and stems turned brown
Asparagus beetle; two generations a year, and the adults overwinter in old stems and debris
Pick off beetles and grubs by hand every few days from the first sighting. Cut down and burn or bin the old ferns in late autumn so the adults have nowhere to overwinter on the bed.
Spears gnawed or scarred at the tip as they emerge
Slugs and snails
Clear weeds and debris from the bed in March, go out with a torch on damp evenings, and apply slug nematodes once the soil is above 5 °C.
Early spears blackened, limp or bent over after a cold night
Frost on emerging spears in April
Lay fleece over the bed when frost is forecast. Cut off damaged spears; the crown sends up replacements.
Plants in one part of the bed yellow, weaken and die, the patch widening each year; roots covered in purple felt
Violet root rot, a soil fungus
No cure. Dig out and bin affected crowns and make a new bed with new crowns on ground that has not grown asparagus or root vegetables recently.
Crowns fail to emerge in spring or produce a few weak spears; roots brown and soft
Crown and root rot on wet, compacted ground
Plant on a ridge or in a raised bed on heavy soil, never walk on the bed, and do not cut beyond mid June.
Tall ferns snapped at the base or rocking in the wind in late summer
Wind rock, which loosens the crown and lets rot in
Run a string between canes down each side of the row in July.
Harvest and rotation
Harvest and storage
Cut spears at 15 to 18 cm with a serrated knife 2 to 3 cm below the soil, mid April to mid June only: nothing in the first two years, a 6-week run in year three, then every 2 to 3 days for 8 weeks before letting the ferns grow. An established crown gives about 10 spears a season. Keep in water or freeze.
Rotation and companions
Rotation: a permanent bed for 15 to 20 years, so no rotation, sited where it will never be dug or trodden. Keep away from onions, garlic and potatoes, whose lifting disturbs the crowns.
Good to knowA 15-year-plus bed, don't cut in the first two years; let the ferns build up the crowns.
Growing asparagus in pots
Asparagus is not a container plant. Each crown makes a mat of fleshy roots more than a metre across and lives for 15 years or more; in a pot it runs out of room within two seasons, dries out in summer and gives a handful of thin spears. If your soil is heavy clay or you have no open ground, build a raised bed at least 30 cm deep and 1.2 m wide and fill it with topsoil mixed with a third coarse grit or sharp sand. That gives the drainage the crowns need and counts as open ground for everything on this page.
Asparagus: common questions
When should you stop cutting asparagus?
Stop by mid June, about eight weeks after the first cut on an established bed. Every spear after that must be left to grow into fern, because the ferns feed the crown for next year. In the third year, the first year of cutting, stop after six weeks.
When do you cut back asparagus ferns?
Cut them down in October or November, once they have turned completely yellow. Cut to about 5 cm above the soil and take the debris off the bed. Cutting while the ferns are still green weakens the crowns and reduces next spring's crop.
How many asparagus crowns do I need?
Ten crowns is a sensible minimum for two people. An established crown gives about 10 spears over the season, so ten crowns give around 100 spears, a modest helping once or twice a week for eight weeks; plant twenty if you want it more often. At 30 to 45 cm apart, ten crowns need a row 3 to 4.5 m long.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.
- How to grow asparagusRHS
- How to grow asparagusBBC Gardeners' World Magazine