What causes this?

Spotted 2 yellow leaves on one of my girls. Not concerned because they are thriving but why does this happen? At first I was sort of alarmed now I’m just curious. Thanks!

It appears those leaves are pretty low on the plant, and hidden in the middle of the canopy..the plant is likely just getting rid of them as they aren't needed for photosynthesis. A pic of the whole plant would help to be sure of that.

You can get a better answer if you post info on the grow, fertilizer used and soil type, etc.

polishpollack said:

You can get a better answer if you post info on the grow, fertilizer used and soil type, etc.

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80/20 Happyfrog/Pearlite. Nutes are MegaCrop, a 1 part from @GreenleafNutrients. First grow

jordanwh said:

80/20 Happyfrog/Pearlite. Nutes are MegaCrop, a 1 part from @GreenleafNutrients. First grow

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Don't sweat it.

Hi Jordan,
The yellowing may hint at an early mg deficiency. Marijuana plants love the stuff. You could add some in...or wait to see if it worsens. It's the yellowing in stripes between the vein that looks like mg def. Just a thought...
JD

pretty nice looking grow space. on the yellowing, lower leaves yellowing usually means low nitrogen or fert amount in general, but it looks like your plants are of a nice medium green color so far. I don't know why you're seeing the yellowing as you are giving fert and the soil comes with fert in it already. be careful how much extra you give as those plants might not need it. with giving extra fert in happy frog, at first I thought you were over doing it on the fert, but the leaves don't show they yellow/brown tip death that is typical of over ferting. the only things I can think of would be a watering issue, a pH issue, or a micro nutrient issue. hard to say at this point. have to let some time pass and see what else develops I guess. I wouldn't give more nutrient however just because I could. that might make a bad problem worse. maybe for now just pluck off the yellowing leaves and see how much the problem continues.

polishpollack said:

maybe for now just pluck off the yellowing leaves and see how much the problem continues.

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Don't pluck the leaves. Most deficiencies are reversible and by leaving the leaves...you can see changes.

Sometimes, a plant will just select a leaf to sacrifice and will use up it's stored nutrients. May be related to leaf damage or insect damage...but I don't think that's what's going on here.
JD

jordanwh said:

Spotted 2 yellow leaves on one of my girls. Not concerned because they are thriving but why does this happen? At first I was sort of alarmed now I’m just curious. Thanks!

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I started having similar issues with lower leaves on certain plants when I switch to Mega crop, I don't use it anymore. The problems stopped after a couple weeks back on GH Flora Trio