How To Grow Asparagus Hydroponically (Complete Guide)

If you’ve got the patience, then it’s growing asparagus hydroponically can be a great new venture for your hobby! However, if you plan on growing hydroponics from seed, then it’s important to know that it’s going to take you three years before you start harvesting.

But if you’re happy to wait, you will be well and truly rewarded! So keep reading to find out how to grow asparagus hydroponically.

What Will You Need To Grow Asparagus Hydroponically?

Should You Plant Seeds Or Crowns?

One of the biggest questions you’ll need to ask yourself when you’re planting your asparagus is whether you want to plant seeds or crowns.

Crowns are going to be ready to harvest much quicker (as they’ve already done a lot of the growing), however, there is a possibility that they will be carrying diseases. The crowns you’ll normally get will be a year old, however, in some cases, you may get crowns that are two years old.

Seeds on the other hand take much longer (3 years before a harvest), but if you buy them from the right supplier it’s far less likely that they’ll be carrying a disease.

Personally, I’d recommend buying crowns so you don’t have to wait so long for a harvest. But if you have the patience then seeds are also a great choice!

What To Know Before Planting Asparagus

Before you plant asparagus, you’re going to need to make sure that you’ve created the best environment for them to grow. This includes making sure the pH, EC, lighting, spacing, and temperature are all as close to perfect as possible.


When it comes to spacing, asparagus is going to need a lot. It’s best to keep them in individual containers, however, if the container is big enough, then it’s possible to keep more than one on it’s own.

You’ll need to make sure you’re also giving them enough space to grow as well. When asparagus does begin to grow it can take up about 4 feet of space, during the first couple of years.

So if you want to grow you asparagus successfully make sure you’re giving each plant enough space. And lastly, make sure the container you’re keeping them in is deep as well as their roots can spread fairly quickly.


When it comes to lighting asparagus are going to need about 8 hours of sunlight a day if you’re keeping them outside. However, if you plan on growing them indoors a 100 watt lamp should be sufficient. Just make sure that all of the leaves are getting equal amounts of light.

If you’re not sure whether your asparagus is getting enough light is by judging the plants color. If the plant is lighter than it should be, you’ll need to increase the amount of light it’s receiving.

pH Level

The ideal pH level for asparagus is between 6-6.8 As you can tell it’s every so slightly acidic.

If the pH of the water is too high or too low, then your asparagus may end up suffering in a number of different ways. In both cases, they’re going to struggle the nutrients they need, which is particularly dangerous to asparagus as they’re heavy feeders.

If the pH is too high then they may end up suffering from leaf cupping and tip burn, however, if it’s too low they may end up having a magnesium deficiency, calcium deficiency, or iron toxicity.

The best way to check the pH of your water is to use a digital pH test kit that you can pick up relatively cheap off Amazon.


The EC of the water should be between 2.4-3.0 (or between 1200 – 1920ppm)

One of the most important things to be aware of is that the nutrients needs will change as your asparagus grows. The bigger your plant gets, the higher the ppm will need to be to sustain it.

So when you’re just starting out you should make sure you’re on the lower end of the spectrum and then slowly raise the ppm up.

If you go over the recommended amount, then your asparagus will suffer from nutrient burn, however, if you don’t give them enough then they’re not going to grow properly and will most likely die.

Temperature (Water/Environmental)

The water temperature that asparagus thrive best in is 71-79°F when they’re seeds and then 75-86°F after they sprout. On top of this, the environmental temperature should be between 70-80°F.

Temperatures that are too hot are going to make it much harder for your asparagus to grow as they’ll begin to suffer from heat stress. Which causes their roots to turn slimy and black before eventually perishing if left untreated.

On the other hand, if the temperature becomes too low, while it genuinely isn’t as problematic it can result in stunted growth. As well as the fern dying of if the conditions match the approach of winter.

Nutrient Requirements

As you now know, asparagus needs a lot of nutrients in order to grow. If you’re just starting out, then JR Peters All Purpose 20-20-20 nutrients is a great place to start. On top of this you should also make sure you’re adding Calcium Nitrate and Magnesium Sulfate.

To mix the nutrients you should use the following guidelines.

For every 5 gallons of water:

  • Before anything else, you should add 10g of calcium nitrate and stir thoroughly. If you add the other ingredients before calcium nitrate then it won’t dissolve properly and this can damage your plants.
  • Next, when there isn’t any visible calcium nitrate left you should then add 5g of Magnesium Sulfate and stir thoroughly.
  • Once you’ve done all this the last step is to add 10g of JR Peters All-purpose 20-20-20. Stir thoroughly once more.
  • If you notice that the pH level changes, then you should add pH up or pH down. The pH should sit between 6-6.8.

You’ll typically need to top up the nutrients every 2 weeks. And if you’re ever unsure about how much you add, the labels of each formula will give you a recommended guide.

What System Is Best?

Due to the long growth times of asparagus, deep water cultures or raft systems are going to be the best way to grow your asparagus. Unfortunately, most people don’t have space for a raft system, so DWC is the overall winner.

How To Grow Asparagus Hydroponically

The way you grow asparagus in the beginning will vary ever so slightly depending on whether you’re going to plant asparagus seeds or asparagus crowns.

Planting Asparagus Seeds

If you’re going to plant asparagus seeds then you’ll need to plant them in rock wool and then place them in a net cup that’s at least 5″ in size. At some point, you’ll also need to perform the tricky task of removing the net cup when you need to move the asparagus somewhere bigger.

When you’re placing them in rock wool, you need to make sure that the rock wool is moist and that you’re keeping it in an enclosed container. This is going to build humidity in the container which softens the shell of the asparagus helping it to grow.

Growing Asparagus From Crowns

Whether you’re starting from seed or growing from purchased crowns, the next steps are going to be exactly the same.

You’ll need to transplant your crowns into your hydroponic system. Here are the steps you’ll need to follow.

Setting Up Your Deep Water Culture

When you’re setting up your container you want to make sure that it’s both deep and has lots of space for the asparagus to spread out. That’s why it’s so important to make sure that you’re buying a large container.

When you’re setting your container up, you should use a large netcup of at least 5″ as asparagus roots grow massively.

You should also choose cover the whole container in about half an inch of clay pebbles to give the asparagus plenty of space to grow.

Once you’ve got this setup you can transplant your asparagus crowns or plant your seeds into the net cup.

Transplanting Your Crowns

If you’re transplanting crowns then it’s important that you make sure they’re not brittle. Before adding them to your hydroponic system you should soak them in water for a day first.

Doing this is going to make them a lot more flexible and it will be much easier to fit them through the holes in your net cup. If the holes in your net cup aren’t big enough, then you may need to make them bigger.

Give It Time To Grow

Now all you need to do is just wait and give your asparagus time to grow. Remember, you’re going to have to wait at least a year if you’re using crowns and even longer with seeds. However, it’s worth the wait.

During the first year with seeds you’ll notice that they grow into ferns. It’s important that you don’t cut the fern as they’re going to help the roots grow better. However, during the first winter (if you’re keeping them outside) you can cut the ferns down to about 1″ once they begin to die.

If you’re not keeping them outside, then you can normally cut the ferns a bit sooner.

The second year you should do the same thing. However, this time you can harvest the ferns that are thicker than your finger, and let the ferns that are thinner than that grow again.

The third year, you should be able to harvest the majority of your ferns, however, ferns that are as a thick as a pencil should be left to grow again.

And finally, after this, you’ll be able to harvest the majority of your asparagus every year for years to come.

Harvesting Your Asparagus

Now it’s time to officially start harvesting your asparagus. When your picking asparagus to harvest, you need to make sure you’re choosing the ones that are ready.

Typically they’ll be 8-12″ in height and the tips should be firm. If they’re not thicker than a pencil or their tips are beginning to unfurl, then you should avoid harvesting them and let them grow again.

When it comes to the actual harvesting, you can choose whether you want to cut your asparagus with a knife or snap it off by hand.

Asparagus Water Changes

Just like every other vegetable, you’ll also need to top up the water of your asparagus as well as change it completely every once in a while. Luckily there is a very simple way to do this.

Every 2-3 days you should check the water levels in your DWC. If you need to add water, make sure you’re keeping an exact measurement of how much water you’re adding.

(If you don’t keep adding more water, then the nutrients in the tank is going to become too concentrated which will result in nute burn.)

Finally, once the amount of water you’ve added equals the amount of water in your DWC, it’s time to change the water completely.

Problems With Growing Asparagus

If you’re going to grow asparagus you should be aware that it isn’t an easy plant to grow. In fact, there still haven’t been any large scale hydroponic asparagus farms.

This is due to two things. First of all, how long asparagus takes to grow. As you now know, it’s going to take between 1-3 years for your asparagus to get to a point it can be harvested successfully.

Second of all, asparagus needs a lot of space to grow. Not only are you not going to be able to grow anything else in the same container as asparagus, but you’re also going to need to give the fern enough space to grow so that the roots can grow properly.

If you’re a beginner, or you’re looking for a way to grow your own asparagus sustainably, then you may be better off growing it in soil. However, if you just want to grow asparagus for fun then it can be a very rewarding plant!

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Common Asparagus Pests

Lastly, if you’re growing your asparagus hydroponically outside, there are a few pests that you need to be aware of. Fortunately, when you’re growing indoors, you don’t have to worry about it at all.

Here are some of the most common asparagus pests to look out for.

Asparagus Beetles

As you can guess from there name, these beetles are extremely common on asparagus plants. They’re blue and red in color and often lay their eggs on asparagus ferns. They’re most likely to infect your crop during the first and second year of growth, but less likely as time goes on.

Asparagus Aphids

Asparagus aphids are another common pest on aphids that you need to be wary of. They grow up to 2mm. They’re greyish green in color and are normally covered in a white secretion.

Fortunately you can remove asparagus aphids by spraying the ferns with neem oil. Not only will this remove and deter aphids, but it will deter other pests as well.

Beet Armyworms

While they’re called worms, they’re actually green caterpillars. You’ll be able to spot them by their distinguishble markings. Going from green to black with stripes running down their sides.

Just like other caterpillars, they’re going to eat the leaves, buds and tips of asparagus. And in some cases, they may even feed on the roots.

Asparagus Miners

These are small maggots that feed on the part of the asparagus stem that is close to the ground. While they cause damage on their own. The real damage comes from the disease causing organisms that they open your asparagus plant up too.


As you can see from the information above. While it’s entirely possible to grow asparagus hydroponically, it may not be the easiest or best choice. Especially for beginners.

However, if you do plan on growing asparagus hydroponically there are a few things to remember.

The first and most important is that you’re going to need to give your asparagus plants plenty of space to grow. Not only are they going to need a deep container for their roots, but they’ll also need space to grow outside too.

Secondly, if you’re growing your asparagus from seeds, you should expect to wait 3 years before your asparagus is ready to harvest. If you harvest it too early, then the roots may not have enough energy to grow.

Lastly, make sure you’re giving your asparagus lots of nutrients. They’re extremely heavy feeders, so you should make sure that they’re getting all the nutrients they require.

If you liked this article make sure you check out the rest of the website. Otherwise have a great day!

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