Do You Need Air Pumps in Hydroponics?

I can still vividly remember purchasing an air pump without even considering the question “do I need an air pump?” Well, that was me as a gardening newbie years ago. Fortunately, I’ve learned a lot over the years, and I would not let you make the same mistake I did.

In general, an air pump is only required for deep water culture hydroponics because the plant roots are submerged in water for a long time due to their need for oxygenation. Air pumps are not strictly needed in hydroponic systems such as nutrient film technique, ebb and flow, wick, and drip systems.

Ever wondered if there was a specific hydroponic system in which plants could be grown without the use of air pumps? Today is your lucky day because I’ll also explain this system at the end of this article. I can’t wait to introduce you to this fantastic system!

Do You Need an Air Pump in Hydroponics?

Air pumps are not required for all hydroponic systems. However, growing hydroponic plants in deep water culture (DWC) is best with an air pump because the roots are submerged in water for a long period of time.

Plants, along with humans and animals, are living things, right? This means all of these organisms need oxygen to breathe—to respire.

Consider spending an entire day submerged in a pool. That’s something even I couldn’t do! I believe the longest I could stay in the water without air is one minute! This is because we would be deprived of oxygen in such a scenario. Plus, even marine animals need oxygen!

The same goes for our plant’s roots. They also need oxygen to breathe and carry out biological processes that will let them grow and bear fruits!

So since the deep water culture hydroponic system grows plants under this condition, providing an air pump will increase oxygen levels in the otherwise stagnant water. In effect, the growth of healthy roots is properly facilitated.

Now, what about other hydroponic systems?

Hydroponic System	Are Air Pumps Required?
Deep Water Culture	Yes
Nutrient Film Technique	No
Ebb and Flow Systems	No
Wicking Systems	No
Drip Systems	No

Hydroponic systems such as nutrient film technique, ebb and flow, and wick systems do not continuously immerse the roots in water. As a result, there is ample air space around the roots of plants grown in these systems for gas exchange.

When we say gas exchange, your roots produce and release carbon dioxide, and at the same process, take in oxygen to let biological functions happen. More of this will be discussed below!

3 Roles of Air Pumps in Hydroponics

Air pumps are beneficial in hydroponics, specifically deep water culture hydroponics.This piece of equipment is responsible for enhanced gas exchange, temperature regulation, and nutrient distribution.

1. Gas Exchange

In hydroponics, air pumps promote gas exchange. They generate bubbles that allow oxygen to enter and carbon dioxide to exit the water’s surface. Higher dissolved oxygen levels enable the roots to perform their role of distributing water and nutrients to the plant.

Let us talk about dissolved oxygen briefly to give you some context. It may sound overly technical, but dissolved oxygen is simply the amount of oxygen in the water. When comparing this to your aquarium, dissolved oxygen is what allows fish to breathe!

The same is true for the relationship between dissolved oxygen and plant roots. As I mentioned a while back, plant roots need to breathe as well! They do it through a process known as cellular respiration.

This is the primary reason why air pumps are recommended for hydroponic systems, particularly deep water culture. Adding an air pump to your DWC system gives your plants’ roots access to oxygen.

Consider the bubbles produced by air pumps. Bubbles have space for air inside, right? This is where the important process of gas exchange happens. This process promotes and accelerates the growth of your leaves, flowers, and, most importantly, fruits!

2. Temperature Regulation

Air pumps elevate water temperature in hydroponic systems because of the pressure generated by bubbles. This is advantageous for those who live in cold climates because it evens the temperature around the hydroponic nutrient water.

By incorporating an air pump into your system, you can also raise the temperature of your hydroponic solution. However, if you are only using one air pump, this should not be a huge concern.

What are the scenarios in which this aspect should be considered? Is it harmful to your hydroponic plants to have too many bubbles?

   If this is something that interests you, head to our article on too many bubbles. 

3. Nutrient Distribution

Water movement caused by air pumps transports hydroponic nutrients throughout the reservoir. As a result, all dissolved nutrients are used to their full potential.

This is somehow similar to putting sugar in a cup of coffee. When you have finished your coffee, you might notice that there are still undissolved sugar particles at the bottom of your cup. This happens because perhaps, you are not able to stir your coffee properly.

In hydroponics, the role of your stirrer is similar to the one that air pumps play in the system. Through the constant pressure and water movement, they make sure that your dissolved hydroponic nutrients circulate well in your water tank.

   Hydroponic nutrients is a long topic, why not head to our more detailed article here?  

How Much Air Does an Air Pump Produce?

A typical air pump can produce at least 500 cubic centimeters (cc) of air per minute in a hydroponic system. This value is equivalent to milliliters (mL) as well, thus, 500 cc is equal to 500 mL.

Most hydroponic systems need 1 liter of air per minute. For home-based hydroponic gardening, a minimum of 500 mL (or a half-liter) will be able to support your plants. However, if you are growing many plants, I suggest sticking to the 1L or 1000 cc air pumps.

But in some air pump products, this information is not explicitly declared on their packaging. So how can you know if an air pump is good for you?

What Is the Appropriate Air Pump Size for You?

When deciding on the appropriate air pump, select the one with a wattage equivalent to the hydroponic reservoir’s gallon capacity.

Here is a trick when buying air pumps! If you have a 5-gallon hydroponic reservoir, you will require a 5-watt air pump.

Don’t be concerned about where to look for this information. The capacity of most market-available air pumps is usually indicated on their packaging! They are usually expressed in gallons.

Here are some air pumps on Amazon with their capacities to help you decide.

This air pump is for a 10-gallon hydroponic reservoir.

The one below is a quiet air pump that can be used for 1-15-gallon hydroponic tanks.

Can You Grow Hydroponic Plants Without Air Pumps?

Hydroponic plants that are grown under the Kratky system, nutrient film technique, ebb and flow system, wicking system, and drip system do not require air pumps.

Deep water culture hydroponics is the only one that cannot grow without air pumps, as I have explained earlier on. But what if I told you that someone developed a deep water culture variation that can support plants even without the use of air pumps?

Let me introduce you to Bernard Kratky, the developer of the Kratky method. In a nutshell, the Kratky method is just deep water culture hydroponics, without air pumps!

Hold up, I can see your forehead wrinkling. Maybe you are asking right now, “but how about the gas exchange lesson you are talking about a while back?!”

Here’s what makes the Kratky method viable. Two words—air space.

In this system, you should not submerge the whole plant root system in hydroponic water. Instead, you should allot enough space for the roots to breathe and perform—yes, you got it right—gas exchange.

How to Set Up The Kratky Hydroponics Method (Tutorial)

FAQs

How long should air pumps run in hydroponics?

For deep water culture systems, it is best to let the air pumps run 24/7. A 30-minute minimum on/off time setting is sufficient for other hydroponic systems; thus, using a timer is also useful for ebb and flow system, drip system, and nutrient film technique if you are using an air pump.

What are ways to aerate my hydroponic water more?

Use one or multiple air pump units if the hydroponic water reservoir lacks significant aeration. Remember that the wattage of the air pump must be equal to the water capacity that the tank can hold. Another way is to use air stones. Using air stones will multiply the amount of bubbles your air pump produces, therefore more dissolved oxygen.

Summary of Air Pump in Hydroponics

Air pumps are required in deep water culture hydroponics, but not for nutrient film technique, ebb and flow, wick, and drip systems. They serve as a major element in gas exchange, temperature regulation, and nutrient displacement.

In choosing an air pump, one must consider the number of gallons the reservoir can hold. This must be equal to the wattage of the air pump available on the market.

One can grow hydroponic plants without air pumps using the Kratky method. This hydroponic system relies on the air space provided to the roots where gas exchange can happen.

Sources

• “Effect of high concentrated dissolved oxygen on the plant growth in a deep hydroponic culture under a low temperature” by Suyantohadi, A. et al. in IFAC Journal of Systems and Control.
• “Indicators: Dissolved Oxygen” by National Aquatic Resource Surveys in the United States Environmental Protection Agency
• “Three non-circulating hydroponic methods for growing lettuce.” by Kratky, B.A. in Acta Horticulturae