Asparagus Growing Guide

5 Steps to Asparagus Planting Success

  • Choose a position in full sun.
  • Prepare your soil with organic matter like compost and sheep pellets.
  • Add a layer of vegetable mix to plant into. In New Zealand plant asparagus from July to December in warm areas and from September to December in cooler areas.
  • Feed asparagus in spring with vegetable food and water regularly. 
  • Cut back the ferny foliage in autumn. Harvest asparagus grown from crowns after two seasons. 

Follow our full guide below to a bumper crop of homegrown asparagus.

When should I plant
in
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  • Harvest in 2 years

The arrival of the asparagus season is eagerly awaited each year. The fresh, sweet new shoots seem to appear overnight from the bare soil. Asparagus crowns can be planted from July to December in warmer parts of the country and from September to December in cooler parts of the country.

A native of Europe, Asia, and North Africa, asparagus will produce tall, ferny-looking stems that can reach heights of more than 2m if left to its own devices. Patience is the main resource required when starting an asparagus patch, as it can take a few years for a crop to begin producing enough to feed the family. It's not a vegetable for the small garden either - it's a perennial that comes back every year, and it needs space to do so.

Choose a variety:

  • Jersey Giant: produces large spears; the flavour is sweet when the tips are small.
  • Mary Washington: a popular early-season asparagus, widely grown throughout the country.
  • Sweet Purple: a neat-looking dark red or purple variety with a sweet taste when young. Generally only available as seed from catalogues.

Prepare

Like building a house a good foundation is the key to success in your garden. The better the soil, the better your plants will grow. Cultivate the soil to a spade depth (approximately 30cm) and blend in organic matter like compost or Tui Sheep Pellets to your soil. Water and leave to settle for a month or so prior to planting. Then you can add a layer of Tui Vegetable Mix before planting.

Plant

The best times to plant are early in the morning or late in the day, so the plants aren’t exposed to the hot sun straight away.

Mature crowns are available as dormant plants over winter, they are a much quicker option than growing asparagus from seed.

Choose a position in full sun. If planting quite a few crowns dig trenches in the soil to plant in. Plant crowns with their roots facing down 15cm deep and 30cm apart. Rows should be spaced at least 50cm apart. Cover with soil.

Shoots will appear as the soil warms in spring. Keep the soil moist but not wet as asparagus crowns will rot in waterlogged conditions.

Sow the seed

Growing asparagus from seed is a slow yet rewarding process - it takes about three years from sowing to harvest. Sow seed in autumn in a seed raising tray. Seedlings should appear within a month. Allow the seedlings to develop for at least one growing season before planting them out in rows the following season. Transplant the seedlings crowns when they are a year old.

Once established asparagus seems to be happy in a sunny, free draining, moist warm soil. In the winter it dies down to the crown and hides underground until the soil warms up again in spring. The cold winters stimulate new season's growth.

Nourish

Feed your plants and they will feed you. Plants use nutrients from the soil as they grow, so replenishing the nutrients ensures your plants grow to their full potential. Feed asparagus plants in spring. Select a fertiliser specially blended for your crop like Tui Vegetable Food or use an all purpose variety, such as Tui NovaTec Premium fertiliser.

Cut back the tall, ferny foliage in autumn.

Protect

Keep your garden weed free and protect your plants from the elements with layers of Tui Pea Straw Mulch to help keep their roots moist. 

Harvest and storage

  • Harvest asparagus grown from crowns after two seasons. If you have grown asparagus from seed don't harvest any spears until the third season as the plants need to mature and establish their root systems.
  • Cut asparagus off at ground level with a sharp knife. Don't be tempted to rip it out of the ground as you will more than likely pull out the whole crown. Eat as soon as possible - the fresher the better - although asparagus will store in the fridge for several days.

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