7 Step Asparagus Crown Planting Method with Gijnlim over a 4-Metre Trench

Dig the trench before the crowns arrive

An asparagus bed is a long occupation of one patch of ground. The plants may remain productive for 15 to 20 years, so the first job is excavation, with the layout fixed before any crown is unpacked. For a single row, mark a 4-metre run with string lines set 90 cm apart, strip the turf, and dig out a trench about 30 cm deep and roughly 40 cm wide.

Keep the spoil clean and close by on a board or sheet. It is used again in stages after planting, so mixing it into paths or turf only creates extra work later.

Gijnlim crowns are usually supplied bare-rooted by firms such as Marshalls or D.T. Brown. They commonly arrive as one-year-old grade stock in March or early April, while still dormant. Each crown has roots radiating from a central growing point, and those roots must stay damp. If the crowns sit in their packaging for more than 48 hours after delivery, heel them into damp compost until the trench is ready.

Once the trench is open, loosen the base with a fork to a further 15 cm. This is especially useful on plots that have been rotavated year after year, where a compacted pan can stop the new roots from driving downward. The loosened bottom should stay in place; it is being opened, not dug out and removed.

Grit, clay, and the ridge line

Gijnlim will grow across a wide pH range, yet it fails quickly where winter water sits around the collar. On free-draining sandy loam the base needs nothing extra. In heavy clay, spread a layer of horticultural grit or coarse sharp sand a couple of centimetres deep along the floor of the trench, enough to break up the bottom rather than form a sealed pan. A 4-metre run swallows the better part of a large bag. Fork it lightly into the lower soil so drainage changes gradually and the base does not become a water-holding sump.

The right material matters. Garden centres usually sell suitable washed grit in the 4 mm to 6 mm range. Builder’s sand is too fine and sets hard.

Over that layer, pull reserved topsoil into a central ridge about 8 cm high. The ridge is the seat for the crowns. Each crown sits bud-up on the crest, with the roots spread down both flanks as evenly as possible. Set the bud so it will finish about 5 cm below the eventual soil surface, and space the crowns at 45 cm centres so all eight fit the 4-metre length with a margin at both ends.

Flat planting on the trench floor leaves the bud more exposed to pooled moisture. The raised ridge keeps the growing point slightly proud of standing water, which matters most in the first dormant winter before the plants have made a strong root system.

Filling the trench without burying the buds cold

With the crowns seated on the ridge and their roots fanned down the sides without sharp bends, cover them first with only 5 to 8 cm of sieved topsoil. Press it gently by hand and keep foot pressure off the row. At this point the bed is still a shallow depression, and that is intentional.

As the ferns emerge and lengthen through May and June, pull the remaining spoil back around them in two or three additions. By midsummer the trench should be level with the surrounding bed. Filling the trench gradually lets the crown settle into the proper depth and avoids smothering the buds under one deep layer of cold soil.

Water after the first covering has gone on. A thorough soak of about 10 litres per metre settles soil against the roots and removes air pockets. During the first dry spell, further watering keeps the new ferns turgid while the crowns establish.

Once the trench has been filled level, add a surface mulch of well-rotted manure or garden compost at 3 to 5 cm deep. Keep it away from the emerging spears themselves.

The first two springs are left alone

No spears are cut in the planting year, and none in the second. The ferns grow unchecked through both seasons so the crowns build reserves. The first light harvest comes in the third spring over a two to three week window, after which all later spears are again left to fern.

Weeds and feeding in a shallow-rooted bed

Gijnlim crowns sit shallow once established, and root disturbance is damaging. That makes hoeing a poor option after planting. Perennial weeds such as couch grass and bindweed need removing from the trench area beforehand, since digging them out later tears asparagus roots.

The cleanest preparation is done the season before planting. Fallow the strip and hand-fork through the top 20 cm, removing every white couch rhizome that appears. Annual weeds after planting are pulled by hand or smothered under the manure mulch.

A 3 cm autumn topdressing of compost helps suppress germination and feeds the crowns as it breaks down. Some growers still use agricultural salt on asparagus beds, relying on the plant’s greater tolerance of salinity compared with many weeds. The practice is traditional and unreliable on clay, where sodium damages soil structure and worsens the drainage that the grit layer was meant to improve. Hand-weeding leaves the asparagus roots and the soil structure intact.

A spring dressing of a balanced fertiliser such as fish, blood and bone, at about 70 g per square metre, is scattered before the spears break through the soil. The ferns stay standing until they yellow in late autumn. Then they are cut to 5 cm above soil level and removed, since dead foliage can carry asparagus beetle eggs through winter.

Costs and yield from the 4-metre row

Eight one-year-grade Gijnlim crowns cost roughly £12 to £18 from a mainstream supplier, with a lower per-crown price when bought in bundles of 20 to 25 for a longer bed. On clay, the bag of grit adds a few pounds more. A 40-litre bag of well-rotted manure covers around 1 to 1.5 metres of row at a 4 cm mulch depth, so three bags finish the 4-metre run.

Through a dry establishment summer the row wants enough water to keep the young ferns standing, applied as a deep soak once or twice a week rather than a daily sprinkle. Once mature, a 4-metre Gijnlim row of eight crowns should yield in the order of 2 to 4 kg of spears over a six to eight week cutting season from year three onward, and continue annually for well over a decade.

The outlay all lands in the first few weeks of work, but the bed gives back nothing measurable until the third spring. What that third-year harvest actually delivers depends on how disciplined the grower was about leaving the first two seasons of fern entirely uncut, and there is no shortcut that lets you test whether you held off long enough until the spears come through.