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RDWC & DWC Tips, Tricks and Techniques
Founder of Current Culture H2O and water culture systems innovator Daniel Wilson recently joined Garden Talk (Episode 182) for an in-depth discussion on Re-Circulating Deep Water Culture (RDWC) growing. It’s an engaging episode packed with practical insights and real-world grow tips you can apply right away to improve results in both DWC and RDWC gardens.
You can watch the full episode here — and we’ve also highlighted a few standout tips and techniques shared during the conversation.
The discussion perfectly reinforces CCH2O’s core philosophy: clarity equals stability, and stability equals yield.
Garden Talk Episode 182 Highlights:
Host: When you’re looking at fertilizer concentrates and the by-products added into solution, what should people watch for?
Daniel Wilson: Clarity is key. If something settles out over time, identify what it is and consider excluding it. Those precipitates often signal instability or an early warning of root-zone issues.
Host: Different genetics can have very different nutrient needs. In a recirculating system with multiple cultivars, one strain may thrive while another struggles. How do you handle that?
Daniel: Great question. This is actually one of the strengths of water culture. It’s similar in some ways to ecological or living-soil gardening—plants interact dynamically with their environment.
In RDWC, a plant that feeds more also draws more solution and nutrients. Because uptake velocity matters, a vigorous plant naturally self-regulates—taking in more minerals even when EC is moderate. That’s why we recommend less-is-more with EC. It allows lower-demand plants to coexist with heavier feeders.
If you must compensate for differences, foliar feeding is a great tool—quick, targeted, and it doesn’t destabilize the root-zone chemistry.
Host: Nice tip on foliar feeding. Anything growers should avoid?
Daniel: Don’t add seaweed extracts to RDWC. It’s great as a foliar spray, but in recirculating systems, the organic load can foul the system.
Host: Some growers bend the rules though.
Daniel: True. If something works for them at a fraction of the dose, that’s valid—it’s about finesse. For example, “Stash Blend” worked well in DWC at quarter strength. Precision and observation always trump rigid recipes.
Host: How about beneficial microbes or enzymes?
Daniel: We run a very clean, mineral-based nutrient program—mainly chelated salts. We do recommend a streptomyces-based inoculant for its targeted, water-culture-compatible activity. It stays dormant until decaying matter appears, then acts to remediate pathogens.
Generally, we tell people to avoid broad-spectrum inoculants or enzyme products that include food sources or carriers intended for soil—those create instability.
Sterility is a myth; you can’t keep a system truly sterile. The goal is clean cultivation, meaning no unnecessary organics, humates, or insolubles. Clarity of the solution is the best indicator that inputs are appropriate.
Host: What about hydrogen peroxide?
Daniel: H₂O₂ is an oxidizer—it breaks down biofilms and organic residues, improving oxidation-reduction potential (ORP). That helps root health, but overuse can damage tissue, just like it burns your skin. Use it cautiously and for short-term corrective action.
Host: Let’s talk grow media.
Daniel: Whenever possible, go media-less. If you need structure, expanded clay pellets or neoprene collars work well. Media adds variables—residues, buildup, and cleaning costs. In commercial setups, media-less systems are efficient and consistent.
Host: Reservoir maintenance—how often should growers top off or change water?
Daniel: We prefer stable water levels using a float valve connected to a top-off reservoir. That reservoir can contain dilute solution to help buffer EC and pH drift.Full solution changes are less frequent than many think. Stability is usually better maintained by topping off and minor corrections rather than frequent complete swaps.