Asparagus is naturally a seaside plant so can do well in Kāpiti. It’s a perennial crop that, once established, can be picked for 20 years- so it’s worth getting things right from the start.
An asparagus bed needs: Full sun, good drainage (sandy soil, or a raised bed if your soil is heavy), fertile soil (add lots of compost and seaweed) water, an occasional splash with sea water. Make sure all perennial weeds are totally removed so you won’t be disturbing the roots for the next 20 years.
Growing from plants: Prepare the bed now, and plant out the roots in August/September. Order some at your local garden centre as they come bare-rooted and often sell out fast.
- Dig a 20cm trench and fill with well-rotted compost. Sprinkle on lime and fish meal.
- Make a raised centre for the crowns, spreading the roots well, 30cm apart. Firm in well.
- Cover with soil halfway up the trench. When the foliage appears, fill the trench in with compost.
- Mulch (seaweed is ideal) and keep well watered.
Growing from seed: Takes longer but is very satisfying- and gives you a year to get the bed well-prepared.
- Soak seed overnight and plant into trays in early spring, potting into a deeper tray when 5cm tall. Space at 12 per tray- they will stay there for a year. Liquid feed every few weeks.
- Weed out the females: girls are all flower, while the boys have thick juicy stems. Plant mostly males (leave a few females to collect more seed)
Use only the strongest plants- compost the others. Be ruthless. Plant out next spring, as above.
- Don’t let new plants dry out (but too soggy and the roots will rot.)
- Don’t pick for the first year- let them get established. Harvest lightly in year 2, pig out in year 3.
- Cut carefully with a sharp knife when about 10cm tall and still tightly closed.
- Dress each spring with fish or bone meal and compost. Protect new shoots from frost and slugs.
- Autumn- cut down yellowing fronds and re mulch around the plants.
(Notes from Kath Irvine, Edible Backyard, Ohau.)