Flushing Water Practice During Flowering

Flushing is the planned use of low-PPM water to clear excess salts from the root zone during flowering. The objective is simple: stabilize uptake, prevent harshness, and protect aroma and resin quality. Flushing works only when pH, irrigation volume, and drainage are controlled.

Use a corrective flush any time runoff PPM rises far above the feed trend or plants show tip burn and dark, rigid leaves. Use a pre-harvest flush in the final 7 to 14 days, adjusted to cultivar and substrate. Corrective flush resets the medium after drift. Pre-harvest flush tapers salts while maintaining color and turgor.

For coco and rockwool, bring runoff down to roughly 200 to 400 PPM above source water, then hold steady. For soil-blend media, moderate toward feed plus or minus 100 to 200 PPM. Keep pH 5.8 to 6.2 for coco and rockwool, and 6.2 to 6.6 for soil. Reverse osmosis or low-mineral water is preferred. If using tap, pre-condition pH. In coco, include a light calcium and magnesium background, about 20 to 40 PPM Ca and 10 to 20 PPM Mg, to avoid cation imbalance during the flush period.

1. Measure feed and runoff baseline: volume, pH, PPM.

2. Prepare 2–3x pot volume of low-PPM water at target pH.

3. Apply in pulses. Let each pulse drain fully.

4. Stop when runoff PPM meets the target band.

5. Resume a lighter feed next irrigation at 80–90% of prior PPM.

6. Recheck runoff on the next cycle and fine-tune.

Coco binds calcium and magnesium. Without a small Ca/Mg background, leaves can pale and curl even while EC falls. Rockwool responds quickly, so EC can drop too fast; shorten pulses if fade accelerates. Soil carries more buffer. Use gentler volumes and a longer taper to avoid shock. In all media, full drainage and air exchange are mandatory. Over-flushing strips nutrients and costs yield. Watch leaf color and runoff trend rather than calendar days. pH drift reduces uptake even at perfect EC, so meter calibration must be routine. Standing water invites root issues; confirm trays empty fast and fans keep the lower canopy dry. Late-stage stress reduces aroma and density; keep climate stable and avoid last-minute recipe swings.

Solar Farm schedules flushing by stage and substrate under a GACP framework. Rooms target runoff bands tied to water source and media. Teams verify with meters each session and adjust within the next cycle. Setpoints, readings, and actions link to lot records and COAs. This discipline keeps late-flower quality steady for cannabis wholesale Thailand and cannabis wholesale Bangkok.