Asparagus

Growing Asparagus from Seed – Is It Worth the Wait?

I’ve been thinking a lot lately about the vegetables we grow year after year.

We sow them, nurture them, harvest them, pull them out – and then a few months later we start the whole process again.

There’s nothing wrong with that, of course. I’m certainly not giving up my tomatoes, beans or pumpkins. But as I begin introducing more perennial vegetables into my kitchen garden, I’m becoming increasingly interested in plants that stay put.

And asparagus has to be one of the best.

Plant it once, look after it well, and an asparagus bed can keep producing for twenty years or more.

Usually we’re told to buy asparagus crowns. They’re quick, convenient and give us a head start.

I regularly grow some from seed.

Yes, it takes longer.

But perhaps that’s part of the point.

Why grow asparagus from seed?

The obvious disadvantage is time. If you plant good crowns, you’re already a year or two ahead.

But seed has a few things going for it.

It’s considerably cheaper if you want quite a few plants, there are often interesting varieties available as seed, and you can raise more plants than you need and choose the strongest ones for your permanent bed.

There’s also something rather lovely about knowing that the asparagus bed you may still be harvesting from in twenty years’ time began with a packet of seeds.

Gardening encourages patience, and asparagus certainly puts that to the test.

When should we sow it?

Here in Central Otago, I like to start asparagus seed in mid-winter, indoors.

Asparagus seed germinates best with warmth, so I sow mine into 'deep root' trays with a lid, then leave them on the kitchen bench, where I can keep an eye on them.

The seeds can be soaked in warm water overnight before sowing. It isn’t essential, but it can help soften that fairly tough outer seed coat.

Sow the seeds about 1–2 cm deep into a good seed-raising mix, water gently and then be patient.

And I do mean patient.

They may take a couple of weeks to appear, sometimes longer, particularly if temperatures fluctuate. Don't assume nothing is happening and empty the pot onto the compost heap!

Eventually a rather delicate little shoot appears.

It doesn't look terribly impressive.

Certainly nothing that suggests, “I’m going to feed you for the next twenty years.”

But give it time.

Growing the seedlings on

Once they’re growing well, I pot the seedlings on individually so they have room to develop a decent root system.

This first year isn't about producing asparagus for the kitchen.

It's about building the plant.

Keep them watered, but not sitting in wet compost, and give them plenty of light. As the weather warms they can gradually be hardened off and moved outside.

By summer they begin producing those lovely ferny tops that we associate with an established asparagus bed.

Leave them alone.

Those ferns are doing an important job. They're feeding the developing crown below ground, and the stronger that crown becomes, the better your future harvest will be.

Choosing the permanent asparagus bed

This is the part I wouldn't rush.

Asparagus isn't something we tuck into a spare corner for a year and move later.

Think twenty years rather than twenty weeks.

Choose somewhere sunny, with excellent drainage, where the plants won't be in the way of your normal crop rotation.

And prepare the soil properly before planting.

In Central Otago, where many of us are gardening with very little natural topsoil, I would spend far more time preparing the bed than worrying about fertiliser later.

Asparagus likes a deep, fertile, well-drained soil.

I'd add plenty of well-rotted compost or aged manure and work on improving the soil structure over a good depth. If you have heavy soil, drainage becomes particularly important. Asparagus crowns don't appreciate sitting wet through winter.

This is one of those occasions when doing the groundwork properly really does pay off.

You are preparing a home for a plant that could still be there decades from now.

And then comes the difficult bit…

Don't harvest it.

I know.

After waiting all that time, a beautiful asparagus spear appears and every instinct tells you to pick it.

Don't.

Young asparagus plants need those spears to develop into fern so they can photosynthesise and send energy back into the crown.

With seed-grown asparagus I would regard the first couple of years as establishment years rather than harvest years.

By the third year you may be able to take a very small harvest from strong plants, but don't get greedy.

Allow plenty of spears to grow on into fern.

Once the plants are properly established, that's when the waiting begins to pay you back.

Looking after an established bed

One of the things I love about asparagus is that, once established, it asks relatively little of us.

Keep the bed reasonably weed-free, particularly while the plants are young. Mulch with compost or well-rotted organic matter, keep an eye on moisture during our hot, dry Central Otago summers, and let those ferns grow.

In autumn they'll begin to yellow and die back as the plant moves its energy underground.

I like that visible reminder of what perennial gardening is really about.

The plant hasn't finished.

It's simply storing energy for another season.

How many plants do we need?

For a household that really enjoys asparagus, I'd aim for somewhere around 10–20 established plants.

That may sound like quite a few when you're sowing them, but asparagus is harvested a spear or two at a time from each plant rather than pulling up the whole vegetable.

And this is another advantage of starting from seed.

Sow extras.

Not every seed will germinate. Not every seedling will become a magnificent plant. Raise more than you need and select the strongest plants for your permanent bed.

Any spares can always find their way into somebody else's garden.

Is growing asparagus from seed worth it?

If your only consideration is how quickly you can eat asparagus, buy crowns.

But if you're beginning to think about your kitchen garden differently, moving towards a more perennial style, then theres nothing nicer than knowing you raised your plants from seed (and in my case seed from plants I have previously raised from seed - grandbaby plants if you will)

And yes, growing asparagus from seed means waiting several years for that first proper harvest.

But there's another way of looking at it.

Those years are going to pass anyway.

We might as well have an asparagus bed waiting for us when they do.