Sounds like good bloom nutes. And half strength sounds just fine. Didn't realize you were getting yellow fans. To a point this is to be expected, so long as it isn't severe. I'm generalizing and you'll have to be the judge.
I'll back off the plain water suggestion if you're leaning towards more feeding. Half strength bloom nutes shouldn't give you an N toxicity unless you used high N guano or substitute in veg.
Phosphorus will leach from your mix easier than nitrogen and potassium. If you're concerned the yellowing is premature, you could alternate feeding/ plain water. This would keep your P level a bit higher than plain water while keeping N and K from building up so much.
I usually feed every watering but I measure the runoff. Once the runoff is stronger than what I'm feeding I'll go plain water once and then back to feeding. This also helps to keep N in check.
EDIT - Your early yellowing could have been due to Magnesium deficiency. This can happen when pH and or Mg level is too low. I bet your bloom nutes have enough Mg for most strains as long as your pH is in range. Some Mg hog strains might need a jolt of CalMag or Epsom salts. If you use mineral lime to buffer your mix, Dolomitic lime has Mg. Calcitic lime only has calcium.
You'll know the difference between N and Mg defs by looking at the affected leaves. N def is usually more even, fading to yellow and tan or whitish before dropping. Mg def starts fading at the tips of the petioles. Mg def also shows yellowing tissue between green leaf veins. Advanced Mg def begins to burn the leaf tips, not unlike too much feeding. It's usually a sign the pH could edge up a little.
But usually after the third or fourth week in flower, Mg absorption subsides and slightly hotter pH no longer shows visible signs of deficiency. That's probably where you are now. IME, the yellowing wasn't N but you'll have to make that call. Best wishes.
I'll back off the plain water suggestion if you're leaning towards more feeding. Half strength bloom nutes shouldn't give you an N toxicity unless you used high N guano or substitute in veg.
Phosphorus will leach from your mix easier than nitrogen and potassium. If you're concerned the yellowing is premature, you could alternate feeding/ plain water. This would keep your P level a bit higher than plain water while keeping N and K from building up so much.
I usually feed every watering but I measure the runoff. Once the runoff is stronger than what I'm feeding I'll go plain water once and then back to feeding. This also helps to keep N in check.
EDIT - Your early yellowing could have been due to Magnesium deficiency. This can happen when pH and or Mg level is too low. I bet your bloom nutes have enough Mg for most strains as long as your pH is in range. Some Mg hog strains might need a jolt of CalMag or Epsom salts. If you use mineral lime to buffer your mix, Dolomitic lime has Mg. Calcitic lime only has calcium.
You'll know the difference between N and Mg defs by looking at the affected leaves. N def is usually more even, fading to yellow and tan or whitish before dropping. Mg def starts fading at the tips of the petioles. Mg def also shows yellowing tissue between green leaf veins. Advanced Mg def begins to burn the leaf tips, not unlike too much feeding. It's usually a sign the pH could edge up a little.
But usually after the third or fourth week in flower, Mg absorption subsides and slightly hotter pH no longer shows visible signs of deficiency. That's probably where you are now. IME, the yellowing wasn't N but you'll have to make that call. Best wishes.
Last edited:
Chomp
