The nutrient solution is placed inside the bucket where there is usually an air stone (connected to a air pump) is also placed. The air stone provides oxygen to the roots, and helps them to keep from suffocating in the water. Then the lid (with the pot) is set on top of the five gallon bucket. From there you have the basic DWC hydroponics system design. The key to the DWC system working is that the plants root system (either part or all of them) be submerged in the nutrient solution. From there you can make many variations, like if you wanted to recirculate the nutrient solution, and weather you wanted to recirculate it using a drip system, misters (aeroponic), or flood and drain. There are just to many variations to cover them all, but I will try to cover the most common ones.
With no recirculating nutrient solution this would be the most basic, inexpensive and easiest. Without using a recirculating system the water level is very important, because the roots that are hanging in air (inside the bucket) are likely to dry out. Also the roots that are in the growing medium (in the pot) wont get any moisture and dry out. So you will want the water level to be just above the bottom of the pot with the plants in it, that will allow the growing medium to wick up the nutrient solution, and keep the hanging roots wet.
Even though it’s a basic system, there are a couple of things that will make it easier to use, and grow your plants. First is, you will want a way to drain the nutrient solution in order to make nutrient changes easier. The easiest way to do this is by simply just securely placing an end cap (or plug) on the drain tube that can be removed to drain the bucket/s. Another easy way is by installing a plastic or PVC “ball cock valve” at the bottom of the buckets.
Simply opening the valve will drain the buckets, then the new solution can be poured in from the top, right on the growing medium without even opening the lid. The next thing is you’ll want to be able to check the water level easily. A simple elbow connector installed in the side of the buckets with clear vinyl tubing running all the way up to the top of the bucket will make it easy to see the water level inside the bucket. Just make sure it’s covered when your not checking it to prevent algae growth in the clear tube.
The most common DWC/drip system
The most common DWC setup is probably the combination drip system, especially when using 2 or more buckets at the same time. Again there many variations on this type of setup you can do. But you wont need the clear tubing on the outside of the bucket for viewing the water level. You can set the water level by the placement of a overflow tube. The height of the overflow tube will keep the water level constant. Each time the drip system waters the plants, it drips down into the bucket filling it to the point of the overflow tube. The overflow tube then drains back to the nutrient reservoir, to be pumped back through the drip system again.
Because the water is recirculating between the buckets and a reservoir, the drain tube with the ball cock valve to drain the bucket with may not be needed. You will be able to just change the nutrient solution that’s in the reservoir. There will still be the nutrient solution in the buckets, but as the new nutrient solution circulates through the system, it will mix with the old nutrient solution. So whether you want a drain on each bucket depends on weather you want to be able to get as much of the old nutrient solution out as you can when doing a nutrient change.
DWC/flood and drain system
The DWC/flood and drain system is fairly simple also, and as always can have many variations as well. The only real difference is how the water is pumped to the buckets. Instead of dripping down from above, the nutrient solution is pumped into the buckets from below the plants, through the water inlet tube. Then when the pump shuts off, the water begins to drain back down through the pump, and through the same inlet tube it was pumped up in.
The DWC/aeroponic system is very similar to the DWC/drip system setup. Again the only real difference is the nutrient delivery system. Where the drip system drips down through the growing medium into the buckets, the aeroponic variation sprays the roots from inside the buckets with misters. The overflow tube would need to be low enough to allow the misters to spray the roots. But the water level in the buckets doesn’t need to be real high anyway, because the misters will keep the hanging roots moist and from drying out. But you do want it high enough to keep a good amount of water at the bottom of the buckets.