How to Finish Asparagus + Prep it for Spring

the asparagus is at the end of its run - the ferns are browning off

Asparagus ferns will likely be tall and green and ferny, and getting in the way of everything! I corral them behind a string-line so as to let them completely finish in peace, and I’m hoping to encourage you to do the same. Let them go full cycle – there is more to this than meets the eye. As the stalks wither, the carbs return to the roots – a nourishing and important step in the process towards an abundant spring crop. Natures design is so very elegant in this way – each plant containing, within itself much of what it needs to flourish.

The asparagus canes have died right off and are ready to remove

In a month or two, when the ferns have completely dried off, chop them down and pile them beside the bed. Take the opportunity to remove any pernicious weeds. Don’t worry so much about soft, gentle weeds – the pile of organic matter you are about to spread on top will knock them right back.

Cover with a most generous layer of mature compost, well rotten manure and/ or the gold star of asparagus food – seaweed. If you cannot get seaweed, re-mineralise by splashing seawater on it a couple of times through the season.

Don’t worry about burying the spears, not only can they easily make their way through, the pile will shrink alarmingly as it decomposes.

If you are on poorly drained or heavy soil, going up will save your crop. Asparagus enjoys moisture and is all the better for not drying out, but it hates wet feet.

Asparagus mulched with a mixed woody mulch
Asparagus in full flight in November. A good showing comes from the Autumn preps

Mulch of course, features. Chop up the old canes and stir them through a homemade brew. Because asparagus is a perennial, let woody/ stalky stuff make up the bulk of it. Spread this on top of your awesome pile of organic matter and let nature do the rest.

Comments

  1. Is it possible to grow asparagus below fruit trees?

    • Hey Jess – yes its possible but they’re aren’t the best of partners. If this was your only option then have a go. Factors to consider – asparagus have very dense mat like roots, so perhaps a few small patches rather than one big concentrated one. The spears knock off really easily so a tree that has a mid summer onwards harvest – ie when asparagus harvest is over. And a bigger tree so as you can the ferns can grow through summer without them being too much of a pain (though they will be a bit!) – a plum for instance. Choose a deciduous fruit tree – the leaf fall, falling on the asparagus for a pleasing easy mulch!!

  2. My asparagus never died down to brown before it started producing again, is it ok/best to chop it down at the end of winter if it hasn’t fully died off?

    • How interesting! I’d leave it be for now and give it the chance to die off as the weather cools – depending of course on where you live. Did you stimulate growth with a big mid season feed I wonder? Or did the weather at your place do the cold then hot dance?!

  3. Jenny Martin says

    When I harvest in spring, I know that I shouldnt harvest every spear. Roughly how many spears per plant should I leave? I plan to harvest for the first time next spring.

    • For your first year don’t harvest any is my advice. And the second year too – or atleast just grab a couple From year three – go for it!

  4. Is it possible to dig up asparagus crowns and move them? And when is the best time to do this?

    • sure is, as long as they aren’t too old – wait until they are dormant and then be sure of a great spot and well prepared bed – plant winter through spring.

  5. Clive Fletcher says

    Greetings Kath, from Rolleston, mid Canterbury. A timely article from you on growing asparagus, as I have a spare raised garden bed which I was hoping to use for this crop. Details: 6mtrs x 1.5 mtrs x 400 mm deep. Runs North to South and is in full sun for 8 hours or more late spring through mid/late autumn, clouds permitting. No shade from trees. What is the best way to set out the plants? I can find two options:
    1. two parallel rows, 250/300mm each side of the centre line, with a single row of plants spaced 300mm apart,
    2. two parallel rows, each side of the centre line, starting at 200/250mm each side of the centre line, with a 300mm wide trench. setting out the plants 3oomm apart in two staggered rows.

    What would be a good variety to plant in my location? Many Thanks

    • Option 2 Clive – offset planting. Though to be fair in time they will all merge together. As for variety I’d get to your local asparagus grower in spring and use their crowns – they’ll have the best regional variety. Also its alot cheaper this way, unless you want to take the time and grow your own from seed, in which case good old Mary Washington is an excellent bet.

  6. I planted ten crowns about 18mths ago and have allowed spears to go to ferns which I cut I cut nack when they turned yellow.
    I see that a spear has appeared from one crown over the lastcouple of days (mid July NZ). What do I do; leave it or remove it?
    Thanks

    Pat

    • Nature is full of surprises! I’d just roll with it Pat. In warmer parts of the world asparagus can shoot year round though compromises on quality are made – the energy stored in the roots via the dying down of the ferns combined with the period of rest + your homemade compost/ seaweed added in winter = good energy supply following season. I wouldn’t worry about one spear – watch and see what happens. Has it been warmer than usual at your place? Or perhaps are you growing it in a greenhouse? Warmth is the usual reason for shooting early.best K

      • Pat Steer says

        Many thanks Kath…second chunky spear appearing from the same crown. I live in the Coromandel in a forest environment…plenty of rain and winds here. Will just leave it/them) and see how this crown performs later in the year…