How To Grow Hydroponic Broccoli (Step By Step Guide)

Broccoli is considered a nutritional powerhouse. This green vegetable has vitamins, minerals, fiber, and antioxidants. Since it’s a cold-weather crop, growing Broccoli hydroponically is difficult, however, this article will give you a complete overlook of how to grow hydroponic Broccoli.

What Requirements Does Broccoli Need?

pH level

As a general rule, pH is crucial in hydroponic gardening. It’s a measurement of acidity and alkalinity from 1 to 14, 1 being very acidic and 14 very alkaline.

It’s generally believed that 6.0-6.5 pH value is in the best range for growing broccoli. pH levels may vary with nutrient mixers and water sources. You’ll succeed if you maintain these parameters, even if the value spikes periodically.


PPM (Parts Per Million) measures the concentration level of particles in your feeding solution. You need to monitor PPM levels to avoid overfeeding and underfeeding your plants. pH value plays an important role in PPM levels. If the PPM becomes too high or low, then it can be harmful to your broccoli. The acceptable range for PPM values while growing broccoli hydroponically is 1960-2450 milligrams/Liter (mg/L).  

EC (Electrical Conductivity) determines nutrient strength by conducting electricity. And it’s a more accurate measurement than PPM. 2.8-3.5 ms is the proper EC level recommended for broccoli.


Generally speaking, each broccoli plant is going to need 12-16″ of space to grow. But this is the bare minimum. Remember if you crowd your broccoli you’ll reduce the head size which in turn will yield less produce.


Keeping the temperature at an ideal level is one of the key challenges in growing broccoli hydroponically. And it’s a critical requirement for its successful growth. The temperature range that’s ideal for broccoli is 60°F.

Because of this, it’s recommended to grow them indoors as a cool environment is preferable.


Light is a big factor that strongly affects the growth and development of plants. Around 16 hours of light per day is the best condition for growing broccoli. If you can’t give them 16 hours of natural light a day, artificial lighting can be used to manage the light in your hydroponic system.

Nutrient Requirements

As broccoli is very nutrient-demanding, proper nutritional support is a must. You can start with a high-quality and all-purpose hydroponic fertilizer. For broccoli, I’d highly recommend Master Blend 4-18-38

If you’re going to grow broccoli hydroponically then follow these guidelines…

For every 5 gallons of water:

  • Add 10g of Calcium Nitrate and stir thoroughly. Calcium Nitrate doesn’t mix with the other nutrients, and it can damage your plants if you don’t add it and stir it thoroughly first.
  • Next, add 5g of Magnesium Sulfate and stir that thoroughly as well.
  • Lastly, add 10g of MasterBlend 4-18-38 and stir.
  • If the pH level becomes too low you should also make sure you’re adding the correct dose of pH down to bring it down to 5.8-6.3.

(Check out how to grow hydroponic cilantro/coriander.)

Time to rethink hydroponics?. In a time when pandemic, climate change… | by  Russ Grayson | PERMACULTURE 3.0 | Medium

What’s The Best Hydroponic Setup For Broccoli

There are six types of hydroponic setups. You could use one of these to grow hydroponic broccoli.

Wick System

A wick system is the simplest and cheapest hydroponic setup. A reservoir, a pot, growing medium, nutrient solution and a strip of clothes or rope as wicking materials are all you need. And then the plants absorb moisture through the growing medium.

The wick systems simplicity to set up and maintain is the biggest advantage of the wick system. However, with wick systems, the harvest can often be smaller than other methods.

Deep Water Culture System (DWC)

Another simpler method that is also effective for hydroponic plants is a DWC. Air pumps are used in this system that bubble the nutrient solution around, and keep the water oxygenated.

It’s the cheapest of all methods and has less waste because it recirculates nutrients better. However, it has a slower growth rate and doesn’t work as well with large plants.

Ebb and Flow Systems

With Ebb and Flow, plants grow in separate containers in this system which makes it popular for home gardening. Water pumps are used to pump nutrient solution from a reservoir to a plants container at a scheduled time.

It’s preferable for the customization and efficient use of water and energy. However, one of the biggest cons includes the pump failing. Which can lead to roots drying. As well as this they’re also prone to algae growth. This system is also known as the flood and drain method.

Drip System

This one is most common at both a commercial and backyard level. Like ebb and flow, plants grow in their own container and you can control whether you want the water to flow faster or slower.

With a drip system, you have a high level of control, however, it might be too much for a smaller setup and you’re prone to clogging using this system.

(Want to know how to grow hydroponic ginger?)

Nutrient Film Technology (NFT)

NFT is used mostly for plants with small roots. The plants can be grown in large tubes or channels and a pump transfers nutrient solution through the water stream. Gravity is used to force water to flow back through the tube. With NFT you need a minimal amount growing medium and it’s an extremely space-efficient hydroponic system. On the negative side, a pump failure would mean it’s all over for the plant. And sometimes the roots can become overgrown, thus clogging the channels.

Aeroponic System

As the name suggests, this one is the most advanced and, appropriately, expensive setup. A container would be filled with gallons of a nutrient solution which then gets sprayed onto roots which hang in the air until they grow longer. They’re often exposed to more oxygen with this method which helps maximize nutrient absorption. This system is not suited for thick organic-based nutrients and it’s not as simple and cheap as the other mentioned setups.

When picking a hydroponic system for broccoli, most systems will work. However, ebb and flow and DWC are popular systems for growing broccoli. NFT systems are the least preferable because the roots may clog the pipes. However, with pipes big enough it could still work.

(Find out how to grow garlic hydroponically.)

How To Grow Broccoli Hydroponically

Now to learn the detailed steps on how to grow hydroponic broccoli.

Find The Perfect Area

A sunny location where your broccoli can absorb sunlight is the main criteria. If you’re growing indoors, having grow-lights is a must, as indoor lights won’t be sufficient to grow broccoli. As well as this, you should control the temperature around the plant too. Premature frost could kill your broccoli if the temperature drops too much.

Prepare Your Rock Wool

Before anything you’re going to need to prepare your rock wool. However, doing so is incredibly easy. All you’re gong to need to do is soak the rock wool in dechlorinated water.

If you’re not sure how to get dechlorinated water, you just have to get regular tap water and let it sit for a couple of hours. If you’re impatient, though, you can also use a water dechlorinator.

Add Your Seeds

Once the rockwool has soaked been soaked in water, the next step is too add your seeds. When you’re adding your seeds, you should add 3-4 seeds to each rock wool cube.

Doing this is going to massively increase the chance of having a successful sprout in every cube. There’s nothing worse than not putting enough seeds in the cube and only getting half the broccoli to sprout.

(Like spice? Find out how to grow hydroponic habaneros!)

Create The Right Atmosphere

Now you’re going to need to create the perfect atmosphere for your seeds to grow.

Get a see-through tub you can put a lid on and place all of your cubes into it. Once you’ve done this add a small amount of water into the bottom of the tub to keep the rock wool moist and close the lid on top.

Now all you’re going to have is leave the tub closed for 4-7 days. By keeping the tub closed you’re going to increase the humidity inside which is softens the seed making it easier for your broccoli to sprout.

To help increase the humidity you should also make sure that a light is shining onto the tub you’re keeping your broccoli seeds in.

Setting Up Your Deep Water Culture

While you’re waiting for the broccoli to sprout you can set up your DWC. To do this, simply get a 5-gallon bucket and using a hole saw cut a 3″ hole into the middle of the lid. This is where you’re going to place your net cup.

Once you’ve done this fill the bucket with water until it’s just reaching about 1/8 up the net cup. This way you’re broccoli will still be able to absorb water, but it won’t be so much that it doesn’t encourage the roots to grow.

Adding The Broccoli To The DWC

Once you notice your broccoli has sprouted, you should leave them for a couple more days before you move them to your DWC. Once you add your broccoli to the DWC make sure that they have plenty of access to light and nutrients.

If you notice more than one broccoli sprouting from your rock wool you should keep only the strongest broccoli and remove the rest to make sure they don’t kill each other.

When they’re still sprouts they’re not going to require as many nutrients as when they’re growing. Around 560ppm will be enough for them. However, as they begin to grow rapidly you should increase the amount of nutrients you’re giving them to about 840ppm.

And of course, you should also make sure you’re giving them sufficient light. If you’re keeping them outside place them in sunlight, and if you’re growing them inside a 100 watt LED light per square foot will be more than enough to keep them healthy and happy.

Just make sure when you’re using LED lights you’re leaving enough space away from your plants so they don’t end up suffering from leaf burn.

Once they’re in the DWC you’ll only need to keep an eye on the pH, EC/PPM, temperature and of course topping off the water.

(Did you know it’s possible to grow asparagus hydroponically!)

Avoid pests

Hydroponic environment is suitable to protect your crops from pests. You need to follow your garden regularly to catch insects entering the premises and lay eggs in your seeds.

When Should You Top Off/Change Water?

You’ll notice that the bigger your broccoli grows, the more water it’s going to use. So you’ll need to top it off every so often.

When topping off the water you’ll need to make sure that you’re giving the roots room to breathe. If they’re always submerged in water, not only are they going to have no incentive to grow down, but they’ll also become much more likely to rot or go bad.

Generally speaking, as they get bigger, you’ll need to top off the water in your broccoli every 2/3 days. This way the nutrients aren’t going to become too concentrated which can cause nute burn.

The most important thing to remember when topping off water is making sure that you’re measuring how much water you’re adding every time.

Because once you’ve top off 5 gallons of water, you should remove all of the water in your DWC and replace it. This normally happens every 15-20 days, but for the best yields should measure it exactly. 

Organic Broadcaster | MOSES

What Are Some Common Pests That Can Affect Broccoli?

Here are some of the common pests and prevention for how to grow hydroponic Broccoli.

Cabbage Worms

Cabbage worms are the larvae of moths and butterflies. If you notice a white or gray moth around your broccoli, then their offspring may soon wreak havoc on your seed. You can control young larvae with insecticides that have Bacillus thuringiensis or spinosad in them. But if you’re trying to be environmentally friendly you can handpick as many as you can.


Aphids are tiny insects that feed on the underside of broccoli leaves. When this happens the broccoli will become discolored and wrinkled. They reproduce rapidly even without mating and feed by sucking sap from plants. You can get rid of them with insecticidal soap or neem oil. Sometimes a strong spray of water from a hose also gets rid of them.

Flea Beetles

Flea beetles are tiny insects that damage broccoli by leaving numerous small holes in the foliage. Once again they’re not too hard to remove. Neem oil and other insecticides can be effective. But Diatomaceous Earth is the best choice. Diatomaceous Earth is essentially microscopic pieces of fossil, that flea beetles inhale. Once inhaled it will kill them from the inside. However, it’s harmless to humans.

(Find out how to grow kale hydroponically!)


Cutworms are particularly dangerous for broccolis as they can cut off young seedlings at ground level. They’re harder to spot as they usually come out at night. You’ll need to wrap the stems of your broccoli either with cardboard or cloth to prevent the damage caused by cutworms.

Cabbage Loopers

Cabbage loopers are small green caterpillars that leave small holes on broccoli leaves. If the problem is small, handpicking them is often enough. A natural bacterial pesticide Bacillus thuringiensis can also be used to prevent the damage.

How Long Before Hydroponic Broccoli Is Ready To Harvest?

If you’re growing your broccoli from seed, then it’s going to take between 100-150 days before it’s ready to harvest. If it grows from transplanted broccoli, 55 to 80 days is the normal time in which it will be ready to harvest.

How Do You Harvest Hydroponic Broccoli?

The final thing to do now is harvest your broccoli! Here’s how!

Check For Signs

When you think it’s time to harvest your broccoli, the first thing to do is check how it looks. It should have a dense set of small pinehead sized green flower buds. And it should also be ready to harvest if it shows yellowing or flowering.

Another sign can come from the growth of the central head. A sign of harvestation time will be when the central head stops growing. Usually they’ll reach about 4 to 6 inches in diameter before this happens.

Gather Your Tools

To harvest broccoli you’ll need gloves, clean and sharp pruners/knives, measuring tape and a container/basket to collect your broccoli.

Measure & Clip The Stem

When cutting broccoli you’ll need to make sure you cut at an angle to prevent rain from rotting the centre of it’s stem. You can cut the stem about 5-8 inches down the stalk below the head. It’s best to make the cut in one motion to avoid stalk tearing

Side Shoot Harvesting

You can check back every 3-4 days for new side shoots to harvest. Once you harvest the main head, the plant may grow side shoots. The process of harvesting side shoots is the same as what you did with the main head.

Rinse And Store

Storing your harvested broccoli in the refrigerator can keep it fresh for up to 5 days. Meanwhile frozen broccoli can be kept for up to a year.

Wait A Week For New Growth

You can remove the entire plant once the side shoots stop growing. Just make sure you wait a week to make sure no more have grown.


Now you’re ready to start growing broccoli hydroponically on your own! Just remember while hydroponics can be a lot more precise than standard gardening, there is still some level of art to it! So make sure you’re experimenting and trying different things to get the best yield possible!

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