An aquarium air pump and air stones are typically used to provide air bubbles to the nutrient solution for water culture systems, as well as other types of hydroponic systems. The air pump provides the air volume, and is connected to air stones with an air line/tubing. The air stones are made of a porous rock like material, the small pores create small individual air bubbles that rise to the top of the water (nutrient solution).
Recirculating Water Culture systems
Another variation of the typical water culture system is a recirculating water culture system. The recirculating system works like a flood and drain system but never drains. You can have as many growing containers (water culture reservoirs) as you want connected to one central reservoir. Each growing container has its own fill line, as well as a drain/overflow tube that drains back to the central reservoir.
Types of aeration
Also, while the plants roots are able to get oxygen when using the Kratky method, the roots above the water line cant get nutrients, and the roots below the water line cant get oxygen because they have already depleted the dissolved oxygen in the water early on, and there is nothing to replace it. That’s a source of stress for the plant. Think of it like being in swimming pool and not being able to move while having your nose above water so you could breath, and having your mouth below the water line and able to drink water so you don’t dehydrate. You can survive this way if you had to, but it would be very uncomfortable.
The term “DWC” is often used incorrectly when describing water culture systems. So what is “DWC,” and why isn’t “DWC” one of the six types of hydroponic systems? Well, that’s because it’s simply not a different type of hydroponic system at all. As you can see by the full name “Deep Water Culture,” it’s just a variation of the already existing type of hydroponic system called a water culture system. The word “Deep” in front is only used to describe some water culture systems when the water depth in the system is deeper than 8-10 inches, then it can be defined as an actual DWC system. However regardless of the water depth, DWC systems are still water culture systems.
While the plants are small the basket is supposed to touch the water so the roots can begin growing out the bottom. As the plants grow and the roots get longer, the plant drinks up some of the water as well. That lowers the water level leaving a air gap. Without the air pump to replace the dissolved oxygen and oxygenate the water, the plant’s need the air gap to be able to get the oxygen from. This type of system design is useful in places where electricity is non existent or unreliable.
There’s often confusion and sometimes maybe even debate on where the water/nutrient solution level should be in water culture systems. Should the basket be touching the water, or hanging just above it? There are pros and cons for both, but there is no right or wrong, it can be either. The water level is also very quick and easy to change in a water culture system by simply adding more water, or taking some out.
Most growers that recirculate the nutrient solution like this for their water culture systems only use an air pump in the central reservoir, rather than in each individual bucket (mainly to save money). They let the water pump run 24/7 all the time. However if you have air bubbles running in each bucket like a typical water culture system, you can vary the on time for the water pump. Also the plants would benefit from the direct contact with the rising air bubbles contacting the roots.
To begin with I first need to say the called Kratky method is not a new or different type of hydroponic system. I say “so called” because it’s really just variation of a standard water culture system, but has sometimes been commonly referred to by a person’s name (renaming it) instead. As far as I can tell, the variation was dubbed the Kratky Method after B.A. Kratky at the University of Hawaii who teaches non-recirculating hydroponic methods.
Water Culture Hydroponic Systems Water Culture System Water Culture systems are about the simplest of all six types of hydroponic systems. While technically simple, they are
Amazon or Pet Store
How much of the roots should be submerged in my DWC reservoir and nutrient solution?
First of all, make sure that only the root matter is submerged in your nutrient solution — no stem, and certainly no vegetation. You don’t want to completely submerge the roots, either. I personally keep about 1-1.5″ of root above the water line. The bubbles from the air stone will typically pop and water will still land on the roots that aren’t submerged, so you don’t have to worry about them drying out.
Before we get into the nitty gritty details, let’s get a high-level overview of this type of system. In a DWC system, a plant’s roots are suspended in a well-oxygenated solution composed of water and nutrients.
- The type of plants you’re growing
- The stage of growth they’re in
- The size of your reservoir
This method is called Deep Water Culture for two reasons. One, you typically grow with a reservoir that can hold a decent amount of water. More water means more stability in your nutrient solution, which means less monitoring and maintenance for you!
This is not a yes or no question. Some hydroponic gardeners want to keep their reservoir sterile. This means they won’t have any of the biological contaminants that might plague a hydroponic garden, like algae. But at the same time, they won’t be able to take advantage of beneficial bacteria. If you do decide to add beneficial biology to your reservoir, just be aware that it comes with the risk of having not-so-beneficial biological organisms tag along for the ride.
Here’s an example:
The traditional method is amazing for beginners, but what if you want to scale your system to the next level? Most people move to a RDWC, or Recirculating Deep Water Culture system when they want to upgrade their garden.
Deep water culture is one of the simplest ways to get into growing plants hydroponically, but it sounds very confusing and complex. Let's break it down!