9 Step Asparagus Crown Planting Method with Gijnlim Crowns from Marshalls

Why a one-year crown beats a packet of seed

Gijnlim crowns from Marshalls arrive as a tangle of pale roots radiating from a central bud cluster, and the reason gardeners pay roughly 80p to 1 pound a crown instead of sowing seed is time. Seed-grown asparagus needs three full seasons before any cutting; a one-year Gijnlim crown brings the first light harvest forward to spring of year two and a full harvest to year three. The all-male F1 designation matters for yield: female plants spend energy setting red berries that self-seed into weedy competition, while Gijnlim throws almost no female spears and routes that energy into thicker, earlier shoots.

The trade-off is that a crown commits the ground. A productive bed runs 15 to 20 years, so the soil work done in the planting week is the only chance to fix drainage, pH, and perennial weed before the crowns are in and immovable. Couch grass and bindweed pulled after planting will tear through the shallow crown roots. That is the case for spending more on bed preparation than on the crowns themselves.

The nine steps, start to finish

The sequence assumes bare-root Gijnlim delivered in early to mid spring, when soil has dried enough to crumble rather than smear.

1. Soak the crowns in a bucket of water for one to two hours on arrival. They travel dry and the roots rehydrate before they go in cold soil.

2. Clear the bed of every scrap of perennial root. Dig over two spits deep, remove couch, dock, and bindweed by hand, and let the bed settle for a day.

3. Test pH and aim for 6.5 to 7.5. Asparagus sulks below 6.0; garden lime worked in a fortnight ahead lifts an acidic plot.

4. Dig a trench 30cm wide and 20cm deep. On heavy clay, add a 5cm layer of horticultural grit to the trench floor first, because waterlogged crowns rot before they ever spear.

5. Build a low ridge of soil down the centre of the trench, around 7cm high. This is the saddle the crown sits astride.

6. Space crowns 30cm to 40cm apart along the ridge, draping the roots evenly down both sides like spokes. Rows sit 45cm apart.

7. Set planting depth: the crown bud should end up 15cm below the finished soil surface on free-draining ground, slightly shallower at 12cm on clay.

8. Backfill the trench in stages. Cover with 5cm now, then top up as spears emerge through the season until the trench is level. Burying the whole 15cm at once can smother weak first shoots.

9. Water in and mulch the surface with 5cm of well-rotted compost, keeping it clear of the emerging spears.

The staged backfill in step 8 is the part most planting guides skip. A Gijnlim crown set at 15cm and buried in one go will still grow, but the first spears expend more reserve fighting to the surface, which shows up as thinner shoots in year two.

Depth is a hedge against frost and drought

The 15cm figure is not arbitrary. A crown sitting 5cm down spears earlier in spring and gets caught by late frost; the same crown at 15cm emerges a week or so later and dodges most April frosts across most of the UK. Deeper crowns also sit in soil that holds moisture longer through a dry June, which matters because Gijnlim spears turn woody and bitter when the plant is water-stressed during the cutting window.

There is a yield cost to going too deep. Below 18cm to 20cm the spear travels so far before it breaks ground that thin shoots simply run out of reserve and fail to surface. The workable band is narrow: 12cm on cold wet clay where you want faster emergence and less rot risk, 15cm on loam, no more than 18cm on light sand that dries fast and where the extra depth buys drought protection. Marshalls prints 15cm to 20cm on the despatch sheet, and the lower end of that range suits almost every garden better than the top.

For anyone growing in raised beds, the depth maths changes. A 30cm raised bed gives only 15cm of working depth once you account for the trench, so the bed needs to be 40cm to 45cm tall to bury a crown properly and still leave root run beneath. Filling that volume with topsoil mixed two parts to one with composted bark keeps drainage open in a structure that has no subsoil to drain into.

Watering without rotting the crown

A Gardena smart watering system earns its place here for one reason: asparagus wants consistent moisture in the first two establishment years and almost none once mature, and a controller enforces that schedule when you forget. The Gardena Smart Water Control valve paired with a soil moisture sensor sets a threshold so the line only opens below a set dampness, which prevents the daily over-watering that drowns young crowns.

In year one, run drip line along the row, not a sprinkler, and target two soakings a week in dry spells, enough to wet 20cm down. Drip keeps the surface dry, and a dry surface gives weed seed less to germinate into. From year three the established bed needs supplementary water only in a genuine drought, because the root system by then reaches 50cm or more and finds its own moisture. A smart controller that you simply pause in summer does the same job as remembering to turn a tap off, with fewer forgotten taps.

Feeding through the long seasons

Comfrey makes a high-potassium liquid feed that suits asparagus once the ferny growth is building reserves for next spring. The recipe is unfussy: pack a lidded container with cut comfrey leaves, weigh them down, and either add no water for a concentrated black liquid drawn off over three to four weeks, or fill with water for a faster dilute version ready in two to three weeks. The undiluted concentrate is strong, so cut it 10 to 15 parts water to 1 part feed before it goes near the bed.

Apply comfrey feed from after the cutting window closes in June through to August, when the fern is photosynthesising hard. The potassium supports root and crown development rather than pushing soft leafy growth that a nitrogen feed would. A spring top-dressing of a balanced fertiliser at the rate on the box, worked into the surface as spears start, covers the nitrogen side. Avoid feeding once the fern yellows in autumn; the plant is shutting down and surplus nutrient just leaches.

The Hotbin Mk2 fits the asparagus calendar neatly because it runs hot enough to break down the tough spent fern that ordinary cold heaps refuse to rot. Cut the fern to ground level after the first hard frost, chop it, and feed it into the Hotbin with a bulking agent; the unit holds 40 to 60 degrees and turns woody fern into usable compost in weeks instead of the year a cold heap takes. That compost goes back as the spring mulch, closing the loop without buying in soil improver.

The first year is a waiting game

Do not cut a single spear in the planting year. Every shoot must be allowed to open into fern and feed the crown, and cutting in year one stunts the bed for its whole life.

What the crown is doing underground while you wait

Through that first summer the visible plant is a few thin spears opening into feathery fronds up to 1.5m tall, and it looks underwhelming next to the price paid. Underground the picture is different. The crown is laying down storage roots and building the bud cluster that will throw next year’s spears, and the volume of fern above ground is the direct measure of how much reserve goes below.

This is why the no-cut rule in the short section above is absolute, and why even in year two the harvest stays light, a fortnight of cutting at most before you let the rest run to fern. By year three a healthy Gijnlim row will spear for six to eight weeks from mid April, and the spears come thick because three seasons of uncut fern banked the reserve. Pushing harvest earlier or longer to get value sooner mines that reserve and the bed declines years before its time.

The discipline reverses ordinary vegetable growing, where you sow and harvest in one season. Here the work concentrates in the planting week and the patience stretches across two springs of looking at fern and cutting nothing worth eating. The crowns that get fed comfrey, kept weeded, and watered consistently through establishment are the ones still spearing well at year 15. The ones cut too early are usually thin and patchy by year eight.

Weeding stays a hand job for the whole life of the bed. The crown roots run shallow and a hoe or fork through them does lasting damage, so a thick compost mulch each spring that suppresses germination is worth more than any amount of cultivation. Bindweed that survived the initial dig will reappear, and the only answer is to trace and pull it without disturbing the crowns.

The figure nobody prints on the despatch sheet

The break-even point is rarely discussed. At roughly 1 pound a crown plus bed preparation, a 10-crown Gijnlim row costs a modest sum that an established bed repays in spears that retail at several pounds a bunch, but only from year three onward and only if the first two seasons were respected. What is harder to find anywhere is how a bed behaves in year 12 or 15 as the crowns age and spear count tapers. Is it better to replant a fresh row alongside an ageing one and stagger the changeover, or run a bed to genuine exhaustion first? On that question the catalogues stay quiet.