WHAT IS DWC?
Deep Water Culture (DWC) is a style of hydroponic growing that does not use a medium. In a DWC setup, the plants are suspended in special pots or nets, with their roots stretching down, immersed into a pool of aerated, nutrient-rich water. Growing plants in a DWC setup can have many benefits as compared to some other growing methods.
There are three required parts of DWC:
- Oxygen: Because the roots are submerged in water and not soil (which has gaps and holes where air resides), the water needs to be well oxygenated so the plant doesn’t drown. This is accomplished with an air pump and air stone.
- Water: Think of this system as if you’re growing in soil and permanently watering your plants – this is one of the reasons growing hydroponically is so beneficial – you never need to ‘water’ again.
- Nutrients: A good quality soil contains all of the micro and macro nutrients that a plant needs to survive and thrive. Because we have no soil, we need to supplement the oxygen-rich water with nutrients so our plants can grow.
Benefits of ALFRED Plant System
ALFRED DWC systems are popular for many different reasons, the primary one being that they’re one of the simplest types of systems to start with. The only system that is simpler is a wicking system.
Here are a few other benefits to growing in a DWC system:
- Very low maintenance once you set it up
- Extremely fast growing time compared to soil
- Very little moving parts and assembly
Common Deep Water Culture Questions
What type of nutrients should I use in my deep water culture system?
Companies offer a variety of hydroponic nutrients, so it can be hard to figure out which is best for you. In my opinion, it’s best to start out with something dead simple like the Advanced Nutrients Series.
Should my reservoir be sterile?
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.
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.
What should my pH and PPM / EC be for DWC?
Just because you’re growing in a deep water culture system doesn’t mean you need to adapt your pH and PPM / EC. The standard range that most plants prefer (pH 5.5-6.5) is fine, however you will want to customize and monitor this based on what stage of growth your plants are in. When they’re putting on vegetation, you want to keep your pH in the higher end of that range, and when they’re flowering, the lower end.
As far as your PPM / EC, don’t blindly follow the feeding schedule on the back of your hydroponic nutrients. They are typically higher than necessary. Try cutting that amount in half and seeing how your plants respond. You can always adjust upwards quickly, while adjusting downwards is more challenging as your plants may have already suffered from nutrient burn.
What should the temperature of my reservoir be?
This is one of the downsides of deep water culture: it can be hard to control the temperature of your reservoir. Aim for no higher than 68°F (20°C). If you get much higher, the oxygen level in your water starts to drop (even if you’re oxygenating with an air pump and air stone).
Also try to keep it above 60°F (16°C). If it goes any lower, your plants think that they’re moving into a new season, typically fall or winter. This means they’ll start to divert more energy towards flowering, which you may not want.
When should I change my nutrient solution?
The longest you should wait before changing out your solution is two weeks, but this is just a general case.
It depends on:
- The type of plants you’re growing
- The stage of growth they’re in
- The size of your reservoir
- If you want to avoid a complete change, you can try to add water with some nutrient solution mixed in to get the right balance again, but this is difficult to do. A complete change may be the better route.
How do I know how much oxygen is in my nutrient solution?
Dissolved oxygen meters are available for sale, but they’re pricy and might be overkill unless you want extreme precision. I wouldn’t recommend purchasing a lower-end one though — they’re not very reliable. The best way to “monitor” your dissolved oxygen levels is simply to do the things that ensure that levels are good, namely keeping the solution at the right temperature and running your air pump.
How much faster do plants grow in a DWC system?
Provided you’re doing everything right, plants grown in a DWC system (or most hydroponic systems) will grow at least 15% faster. I have seen my lettuce grow almost twice as fast in my deep water culture setup vs. my outdoor garden.