Asparagus

1. 1

   Choose all-male F1 cultivars

   Modern all-male F1s (Gijnlim, Backlim, Mondeo, Pacific 2000, Stewart's Purple) give 30–50% more crop than older mixed-sex varieties (Connover's Colossal, Martha Washington). All-male plants don't waste energy producing seed; bigger spears, longer cropping life. Worth the premium price.

2. 2

   Prepare the bed the previous autumn

   Full sun, deep well-drained soil. Fork in two barrowloads of well-rotted manure or compost per square metre — asparagus is in this bed for 20 years and won't be re-fed easily. Asparagus hates waterlogged soil; if your ground is heavy, build a raised bed.

3. 3

   Plant crowns in spring

   March to April, bare-root. Dig a trench 30 cm wide and 20 cm deep. Make a ridge of soil 5 cm high down the centre of the trench. Set crowns 30–45 cm apart along the ridge, draping the roots down both sides. Cover with soil to fill the trench level; water in.

4. 4

   Mulch annually

   Each March or April, top-dress the bed with 5 cm of well-rotted compost or manure. Asparagus loves a deep mulch; it conserves moisture, feeds the crowns, and suppresses weeds.

5. 5

   Don't cut in year one

   The hardest step. Let all the spears grow into tall ferny foliage in the first season. The plants need this year to build up the crown reserves. Cutting spears in year one stunts the bed for life.

6. 6

   Light pick in year two

   In year two, cut a few spears (no more than 4 weeks of picking) and let the rest grow up to ferny foliage. From year three onwards, full picking from late April to 21st June.

7. 7

   Cut spears at ground level

   Spears are ready when 15–20 cm tall and the tips are still tightly closed. Cut with a sharp knife 2 cm below soil level, taking care not to damage other developing spears. Pick daily during the peak in May.

8. 8

   STOP picking on 21st June

   The rule that protects the bed. After 21st June, let any further spears grow up to ferny foliage. This rebuilds the crown reserves for next year. Cutting later weakens the crowns and shortens the productive life of the bed.

9. 9

   Cut down foliage in autumn

   When the ferny foliage yellows and dies back in October–November, cut it down to 5 cm above the ground. Compost the foliage (no diseases of concern). Top-dress with compost in spring; the crowns sprout fresh spears in April.

10. 10

    Watch for asparagus beetle

    Bright red and black beetles with their grey larvae strip the ferny foliage. Hand-pick in summer; encourage ladybirds. Severe infestations weaken the crowns over years; light infestations the plants tolerate.

Asparagus beetle is the main pest; otherwise fairly trouble-free once established.