Cannabis Leaves Curling or Taco-ing

Signs

• ●Top leaves curling up like tacos
• ●Tent temp above 85°F at canopy
• ●Leaves closest to light affected worst

Fix

• ✓Raise the grow light 4-6 inches
• ✓Increase exhaust fan speed
• ✓Add intake fan if temps are still high
• ✓Target 72-82°F at canopy

Signs

• ●Top leaves curl up AND tips turn yellow/white
• ●Light is too close (< 18" for 3000K LED)
• ●PPFD above 1000 at canopy without CO2

Fix

• ✓Raise the light or dim it
• ✓Measure PPFD with an Apogee or phone app
• ✓Target 600-800 μmol in veg, 800-1000 in flower

Signs

• ●Leaves droop and curl downward from the tip
• ●Heavy, waxy look
• ●Soil wet 3+ days after watering

Fix

• ✓Let soil dry completely before next water
• ✓Check drainage — drill more holes if needed
• ✓Lift pot before watering — only water when light

Signs

• ●Dark green, almost black leaves
• ●Leaf tips curl down hard — classic "claw"
• ●Happened after feeding

Fix

• ✓Flush with 3x pot volume of pH'd water
• ✓Reduce feed strength by 50% for next 2 feedings
• ✓Wait for new growth to come in lighter green

Signs

• ●Only the leaves directly in fan path affected
• ●Leaves look dried out, curled, brown edges

Fix

• ✓Move fan further from canopy or aim it at the wall to deflect
• ✓Aim for gentle leaf flutter, not whipping