DWC (Deep Water Culture) Setup Guide
Deep Water Culture is the most popular hydroponic method for cannabis. Plants grow with their roots suspended in oxygenated nutrient solution, leading to explosive growth rates and impressive yields.
How DWC Works
In a DWC system, cannabis plants sit in net pots above a reservoir of nutrient-rich water. An air pump and air stones keep the water heavily oxygenated. The roots hang down into the solution and can absorb nutrients directly and continuously — unlike soil where nutrients are released slowly. This direct access to oxygen and nutrients is why DWC produces faster growth than almost any other method.
Equipment You Need
A food-grade opaque reservoir (10–20L per plant), net pots (5–10cm), hydroton/clay pebbles (to support plants in net pots), an air pump and air stones, airline tubing, a water pump for reservoir changes, pH meter (essential — not optional), EC/TDS meter, pH up and pH down solutions, and hydroponic-specific nutrients.
Setting the Right pH
DWC pH must stay between 5.5 and 6.5 at all times, with 5.8–6.2 being ideal. Outside this range, nutrients lock out even when present. Check pH every 24–48 hours minimum. pH drift is normal and expected — you will be adjusting frequently. This is why a reliable pH meter is absolutely non-negotiable in hydroponics.
Nutrient Solution Management
Mix your nutrient solution at the manufacturer's recommended strength, starting at 50% for young plants. As plants grow, increase EC (electrical conductivity) gradually: seedlings 0.8–1.2 EC, veg 1.2–2.0 EC, early flower 1.8–2.5 EC, late flower 2.0–2.8 EC. Change reservoir water completely every 7–14 days to prevent salt buildup and pathogens.
Common DWC Problems
Root rot (brown slimy roots) is the most common DWC problem — caused by insufficient oxygenation, high water temperature, or light leak into reservoir. Prevention: keep water temperature at 18–20°C, ensure heavy oxygenation, block all light from reservoir. Treat with beneficial bacteria products (Hydroguard, Great White) at first sign.
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Quick Tips
- Paint your reservoir black inside and out — algae needs light to grow and will devastate your root zone.
- A water chiller is worth the investment in warm climates — root zone temperature is critical in DWC.
- Always mix nutrients into pH-adjusted water, never add pH up/down directly to nutrient solution.