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How to Propagate Asparagus to Increase Your Plant Stocks

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picture of asparagus in a basket

Asparagus is a delicious and nutrient-dense spring vegetable, but because it’s so expensive to buy in stores, it’s not a common addition to many tables at dinner time. If you grow your own, though, it doesn’t have to be saved for special occasions!

Carrying out propagation techniques, such as division, will allow you to increase your stock of asparagus plants. Asparagus is simple to propagate, and your new and original plants will benefit from the process.

Since planting my first Asparagus crown, I’ve enjoyed bountiful harvests year after year, without having to set foot in a store and with minimal effort in the garden. I’ve found that the best way to maintain yield is to propagate from my existing plants.

In this post, I’ll be giving you the best method for propagating your asparagus with minimum effort, so you can multiply your plant stock and enjoy maximum results!

Before you think about propagating from your existing asparagus plants, make sure they have been established for four or five seasons. Asparagus will only be ready to harvest in its second or third season, so there is no benefit to increasing your plant stock before then.

Why Should I Even Propogate Asparagus?

One of the main reasons to propagate your asparagus is to increase your plant stocks. This, in turn, will allow you to enjoy even better harvests. But it’s not the only reason to do it. You’ll also be benefiting from the health of your original asparagus plants.

After a few years in the ground, your original asparagus crowns will have spread out beneath the soil surface. They are rhizomatic plants and will be creating new crowns that will start sending spears up to the surface.

This is great, to begin with. You’ll see fantastic harvests for a few seasons.

Around year five, though, the plants can begin to get a bit crowded under the ground. Roots become tangled and cramped, competing for moisture and nutrients.

Asparagus can also begin to experience rhizome auto-toxicity. This will eventually lead to lower yields because the plants will be weaker. By dividing your asparagus, you will help slow down this process, and you’ll enjoy the yummy green goodness for longer!

How To Propagate Asparagus Step By Step?

You can propagate your asparagus by dividing the existing crowns. It only needs to be done every five years, as your divisions will take a while to establish themselves once planted, and disturbing them could be damaging.

Here’s how to do it

Step 1

The first and most crucial step in your propagation journey is to prep the area you will plant your asparagus divisions to transplant quickly. The crowns are used to being snug under the rich, dark soil, and too much time spent out of it will shock them and affect their ability to establish.

Clear the area of weeds and debris, then incorporate a generous portion of well-rotted organic matter into the entire site.

Make sure that you do a soil pH test. Asparagus will thrive in neutral conditions, at around 6.5-7.0.

Next, prepare a trench around 6-7 inches in depth. The length of your trench will depend on the number of crown divisions you end up planting. They will need about 18 inches of space between each crown, so, for example, five peaks would need over 90 inches (7.6 feet).

If you end up with more divisions than expected, you’ll need to do some speedy last-minute trench digging!

I’ve got a handy video guide to planting asparagus, which will work well for planting your divisions, too. Watch it below.

Step 2

Wait until the end of winter, or the beginning of spring, when the plants are still dormant. Select solid and well-established plants and dig the crowns up with care – you want to keep the root systems intact as much as possible so that the plant can establish again quickly.

Step 3

Once you have your crowns lifted, please take the opportunity to remove any weeds that may be tangled in the roots so that they won’t be joining your asparagus in its new planting spot. Water the crowns at this stage will help minimize the shock of being removed from the excellent moist soil.

Step 4

After five years, your original asparagus crowns will have spread out under the ground and will have produced several ‘baby’ crowns that are connected by the mature rhizome. It’s these that you will be separating for replanting.

Use your hands to untangle as much of the root system as you can before you start to divide the crowns. As I mentioned earlier, it’s vital to preserve as much root as possible to establish its easy for your divisions.

Step 5

Use the sharpest garden knife you have, and cut downwards between the crowns to separate them. Some roots may be too tangled to sort with your hands, so it’s OK to use your knife to trim them. Just take care to do this as little as possible, though. You want to hang on to those precious roots!

Step 6

Now that you have all your lovely, fresh crowns separated, it’s time to plant them. But first of all, tuck your original plants back into their beds and water them in well. Mulch their bed with a few inches of well-rotted organic material to help moisture retention and suppress weeds.

They’ll need some time to settle, so either give the harvest a miss this year or be very sparing if they appear strong and put out a healthy yield.

Take your divisions to the trench that you prepared at the start of the process. Shore up a mound of the excellent, rich soil you mixed along the middle of the trench. At 18 inch intervals, place your asparagus crowns on the mound and arrange their roots over the sides of the mound.

A word of warning here – look carefully for the small, white spears beginning to emerge from the crowns. You’ll need to make sure these are facing upwards when you plant!

Step 7.

You can now fill in the trench, covering the crowns with the soil and compost mixture. Just like you did with the original crowns, you should mulch the soil surface to give your new crowns an extra blanket of moisture, nutrients, and weed protection.

An excellent organic mulch to use is straw. It will not increase soil acidity as it rots down. You may see advice telling you to use sawdust, but this will increase soil acidity so that I wouldn’t recommend it.

How To Care for New Asparagus Crowns?

Although you have propagated these transplanted crowns from established plants, you should still treat them as though they are brand new to your garden.

  • Keep the soil moist. As long as you have free-draining sandy loam, water the new beds regularly, especially in hot weather.
  • Asparagus is a hungry chap, and will suck up the nutrients from the ground very quickly. Give the soil a feed at the start of this first season with a general-purpose fertilizer like 10-10-10, or blood, fish and bone, at a concentration of roughly 1.5 pounds per 100 square feet. Repeat this process once more at the end of the growing season.
  • Once the feathery fronds have appeared, it’s a good idea to support the stems this year, especially if your garden is windy. If the stems are snapped, the crowns could be disturbed beneath the soil.
  • Weed the bed by hand this year, even though the hoe is so helpful and tempting to use! The new crowns have a fairly shallow root system, and using any instrument on the soil surface is likely to disturb them.
  • You should also avoid the temptation to try and harvest from the new plot, certainly this season and perhaps next season too.

All this TLC may seem like a hassle just now, but I promise it’s worth the work! When your plants are given the right conditions and plenty of time to establish themselves, they will perform at their best, and your harvests will be more plentiful than ever!

Conclusion on How to Propagate Asparagus

I hope this post has clued you in on the benefits of propagating from your existing asparagus plants. Not only will you increase your plant stocks, but you’ll also be doing wonders for the health and longevity of your original asparagus plants.

Although asparagus takes patience to get started, it makes up for that with its stamina. So get dividing and happy munching! If you treat your plants right, as I’ve described here, you’ll be enjoying this early spring delicacy for the next twenty years or more!

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