Why Are My Leaves Curling in DWC or RDWC?
Check where it starts, what else you see, and what the DWC or RDWC system is doing before making a correction.
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Why
Before changing the feed or treating the plant, take a picture. Note which way the leaves curl, where it started, what other signs you see, and whether one plant or the whole system is affected.
If the entire plant is limp, check the system first: power, bubbles and flow at every site, water level, solution temperature, and roots. Look for loss of firmness, slime, shedding, or an off smell. Root color alone can mislead because nutrients and additives can stain healthy roots.
Growers call upward-folding edges tacoing or canoeing. Downward-hooking tips are clawing. Praying means the whole leaf angles upward toward the light. Praying alone is not the same as curling or proof of a problem.
When the edges fold upward near the canopy top, check leaf-level temperature, light intensity or distance, humidity and VPD, and direct fan or HVAC airflow. Upward curl puts canopy stress on the list. It does not prove light burn or a calcium deficiency.
When tips hook downward and the leaves stay firm and dark, review recent feed changes. Calibrate the EC meter, compare the EC trend with the plant's normal baseline, verify the nutrient recipe, and inspect the roots. Excess nutrients, including nitrogen, may move higher on the list, but a claw alone cannot diagnose the cause.
When new growth is twisted, puckered, or malformed, check the pH trend and meter calibration, root health, the complete nutrient mix, recent sprays, and leaf undersides with at least a 20-power loupe. If the damage suggests mites but you cannot find them, use stronger magnification or have the plant tested. Do not add Cal-Mag just because a leaf curled.
If all plants change together, investigate the shared reservoir, environment, and equipment. If one plant changes, inspect its air, return flow, roots, and pests. If only one side is affected, check localized light, heat, airflow, or chemical contact.
Make one targeted correction when practical, then watch whether the problem stops spreading and new growth develops normally. Older damaged leaves may never flatten completely.
Remember the order: shape, location, associated signs, readings, roots and pests, correct one cause, then watch new growth.
Related Grow Pops answers: https://www.growpops.com/grow-answers/what-is-vpd-and-does-it-really-matter and https://www.growpops.com/grow-answers/why-are-my-leaf-tips-turning-brown-in-dwc-or-rdwc
What to remember
- Tacoing, a firm downward claw, and praying are different clues. No shape proves a cause alone.
- Check the pattern, system, readings, roots and pests, then correct one likely cause and watch new growth.
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