What a Soil Feeding Chart Does

A cannabis nutrient feeding chart for soil is a week-by-week schedule of nutrient doses, pH targets, and runoff EC ranges. Unlike hydroponic charts, a soil chart accounts for the soil's cation exchange capacity and slow release of organic matter. You feed less often, every other watering on average, and you rely on runoff tests to see if salts are building up. The chart gives you a starting point. Your plants, water quality, and soil mix will push you to adjust.

How to Prevent Nutrient Burn During Feeding

Prerequisites

  • Living soil or a peat-based mix with perlite
  • Base nutrients (grow and bloom)
  • Calcium and magnesium supplement
  • pH meter with 4.0 and 7.0 calibration solutions
  • EC or PPM meter
  • Clean water, preferably filtered
  • Notebook or spreadsheet

How to Follow the Chart

  1. Test your source water. Record its starting pH and EC.
  2. Mix base nutrients at one-quarter of the label's soil dose for week one.
  3. Adjust pH to 6.2 to 6.5 for vegetative growth or 6.0 to 6.3 for flowering.
  4. Water until 10 to 20 percent of the volume runs out the bottom.
  5. Measure the runoff pH and EC. Write both numbers down.
  6. Compare runoff EC to input EC. If runoff is more than 0.4 higher, reduce next dose by 20 percent.
  7. Increase nutrient strength by 10 percent each week until runoff EC stays within 0.2 of input.
  8. Flush with plain pH-adjusted water every three to four weeks if runoff EC keeps climbing.
  9. Switch to bloom nutrients when you flip to 12/12 light. Keep some grow nutrient for the first two weeks of stretch.
  10. Stop all nutrients two weeks before harvest. Water with plain pH-adjusted water.

Vegetative Stage Soil Chart (Weeks 1 to 4)

  • Week 1: base grow at 1/4 strength, EC 0.6 to 0.9, pH 6.2 to 6.5
  • Week 2: base grow at 1/2 strength, EC 0.9 to 1.2, pH 6.2 to 6.5
  • Week 3: base grow at 3/4 strength, EC 1.2 to 1.4, pH 6.2 to 6.5
  • Week 4: base grow at full strength, EC 1.4 to 1.6, pH 6.2 to 6.5

Flowering Stage Soil Chart (Weeks 1 to 8)

  • Week 1: grow and bloom at 50/50, EC 1.4 to 1.6, pH 6.0 to 6.3
  • Week 2: grow and bloom at 25/75, EC 1.5 to 1.7, pH 6.0 to 6.3
  • Week 3: bloom at full strength, EC 1.6 to 1.8, pH 6.0 to 6.3
  • Week 4: bloom at full strength plus PK booster, EC 1.8 to 2.0, pH 6.0 to 6.3
  • Week 5: bloom at full strength plus PK booster, EC 1.8 to 2.0, pH 6.0 to 6.3
  • Week 6: bloom at 3/4 strength, EC 1.4 to 1.6, pH 6.0 to 6.3
  • Week 7: bloom at 1/2 strength, EC 1.0 to 1.2, pH 6.0 to 6.3
  • Week 8: plain pH-adjusted water, EC 0.0 to 0.4, pH 6.0 to 6.3

Signs You Need to Change the Chart

  • Leaf tips turn brown and curl up: nutrient burn. Lower EC by 0.3.
  • Lower leaves turn yellow while upper leaves stay green: nitrogen deficiency. Raise grow nutrient.
  • Red stems and slow growth: phosphorus or magnesium shortage. Check pH first.
  • Runoff EC above 3.0: salt buildup. Flush with three times the pot volume of pH-adjusted water.
  • White crust on soil surface: salt accumulation. Scrape off the top inch and replace with fresh soil.

Why Convenience Still Needs a Chart

Pre-mixed nutrient lines and self-watering pots make soil growing more convenient than ever. But convenience does not remove the need for a feeding chart. A chart turns guesswork into a repeatable routine. It also helps you spot problems before they cost you a harvest. Keep your records. After two or three runs, you will have a custom chart for your soil, water, and strain.

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