Whether you need an air pump or not depends on which method you’re employing in your hydroponics setup. Let’s just say that if it’s DWC (Deep Water Culture) or Aquaponics, then the answer is absolutely YES!
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Plants Need Oxygen
As early as elementary school, we learn that oxygen is vital for plants.
In its crudest form, we’re taught that via their leaves, plants take in all the carbon dioxide that we breathe out. Then, they release oxygen that we inhale, in an air exchange that’s kept the plant ticking over for billions of years.
As we get older, we realize that it’s not quite that simplistic, of course. And to further complicate matters, neither is the answer to this article question! But we’re here to do our best to help.
Plant Roots Need Oxygen
It’s not just the leaves that need O2 to photosynthesize. It’s the roots, too. And in order for a plant to grow and do well, the plant's root must have access to plenty of oxygen.
Soil doesn’t just protect delicate roots from the elements, but it’s also nutrient rich and with a whole heap of oxygen.
The reason hydroponics is so fascinating is that it’s truly a revolutionary method of growing plants because it doesn’t involve soil at all. Instead, the plants are put into water. And yet, it’s not as simply as dumping plants into water and waiting for them to grow.
When hydroponic gardening, submerging the roots in water can kill off a plant if the water doesn’t contain enough oxygen. So, a lot of thought and preparation goes into providing the right kind of water.
What’s the Right Kind of Water?
Hydroponics reap the best rewards when using distilled water, topped up with added nutrients. Distilled water is purified water that has been removed of contaminants such as pesticides.
Adding nutrients such as magnesium, phosphorous and nitrogen gives your hydroponic plants the best chance of growth as you top them up with everything they need, as well as balancing out the pH of the water for optimum results.
You can even separate the plants out according to their different stages of growth, using different nutrients for each stage. And yet, the one constant throughout is the need for plenty of oxygen.
Air Pumps Boost Oxygen
This is particularly important in the case of a DWC system, or Deep Water Culture. In these cases, the roots are usually planted in a cup or net and the roots dangle directly into the water. Stagnant, non-moving water would result in very little dispersal of oxygen.
An air pump assures that plenty of oxygen moves throughout the water, so every one of the submerged roots gets its equal share. The delivery of oxygen to the roots is imperative for nutrient absorbtion. It works the same way as the heart of the human body, pumping oxygen-rich blood so that every cell in the body receives its share.
Air pumps are also necessary for aquaponics. This makes sense because growing plants using this method involves cultivating aquaculture at the same time, such as fish or shrimp.
Fish tanks must have oxygen-rich water for the fish to survive, and in turn their effluent-rich water is diverted to plants for them to absorb the nutrients it contains.
Air Pump or Water Pump?
You might think they’re both the same, but there are differences between a commercial air pump and a water pump.
Water pumps move around the water that’s in the reservoir or tank without adding extra oxygen, while air pumps not only move the water but infuse oxygen into it, too.
Not All Hydroponic Methods Require an Air Pump
Granted, not all hydroponics enthusiasts use the Deep-Water Culture method. A lot depends on the kind of plants being grown. DWC is best for lighter, thirstier plants, such as lettuce or kale, as opposed to drought-friendly plants like herbs or cacti.
Then there’s the Kratky method, which is an ingenious way of employing hydroponics without the use of an air pump.
The idea is that there’s a plant sitting in a little water, and as the roots grow, the water they’re sitting in is both absorbed by the plant and evaporated by the air. As the water level drops, the roots become exposed to the air, and they absorb their oxygen this way.
The Kratky method is particularly effective for those implementing hydroponics in a place with limited resources or budget.
A wick hydroponic system is similar in that the water doesn’t need a pump. Instead, a wick system dangles from the pot into the water, which travels up to water the plant while exposing the roots to the air for oxygen. Another low-cost, great way to start your hydroponics adventure.
How Big of an Air Pump do you Need?
If the DWC method or similar is the one for you, a hydroponic pump is vital. But how big should it be?
One rule of thumb to adopt is that you purchase a pump with power that equals out to the size of the tank, in a formula where 1 watt = 1 gallon of water in the tank or reservoir.
That could be overdoing it, though, and plenty of people do well with an air pump where 1 watt per 2 gallons of water gets plenty of oxygen into their reservoirs.
Submersible pumps are less expensive than airlift water pumps, but they have a tendency to heat up quickly which could impact the heat of your plants, especially if they need to be at a specific temperature.