Bottom leaves curled at the ends?!?

What type of water are you using (tap, RO, distilled) and do you have any idea what the water temperature is? Those are the first things I’d check. If it’s tap water you might want to let it gas off longer or filter it, if it’s distilled/RO then it’s probably temperature-related.

Distilled water and h20 temps 68ish

Temp has never gone above 70

If it’s not that, it might be the nutrient concentration/composition is incorrect or too high/low; somebody else might recognize those markings and be able to tell exactly which is being OD’d on or is too low.

To rectify that you can just drain/fill again to clean up the water and re-dose nutrients; on new units during the first runs of the pumps sometimes it pulls air instead of fluid and doesn’t actually get enough of the nutrients into the water. Given temps are fine this would be my next guess as to what the problem might be.

The very last thing to check on is perhaps it’s just reading the wrong pH value, is the probe clean+calibrated? Do you have a calibration kit or have you already used one prior to the grow? If it’s the first grow in a new unit this is unlikely to be the issue (but not to be ruled out entirely).


Raising RH can help through struggles like that as well. What’s that reading looking like?

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New grobo first grow h20 temp 68.7 rh 40% (is that to low) the spots are increasing on bottom leaves but uppers are still growing and looking good. I will try to do a drain fill later today to see if that helps

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Those numbers look good. 40% RH is fine, higher is better but I’ve grown around 20% RH so that’s probably not the issue here.

Is your cocopod super-wet?

I would not call it super wet it’s moist which I am assuming is normal how you want it roots look good (they are all white not brown like the picture is making it look)

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The bottom leaves also feel kind of crispy which has me worried

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My current best-guess would be that it’s nitrogen lockout, probably from incorrect pH but perhaps from not having the right ratio of nutrients dispensed (the air in lines possiblity).

If after doing a drain/fill it doesn’t start to look better after a few days (on the new growth, the old stuff won’t heal much/at all) then it might take a probe calibration to rule pH out.


I notice the probe is not sitting in the socket, it’s raised quite a bit. Are both of your probes high up like that?

They should sit flush with the black cap part touching that white fixture that holds them.

I doubt this is an issue just FYI. The pH probe does look to be seated correctly in the corner of your pic.

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It looks like this both spots are small holes the other probe does not have this cap on it that’s why it’s up higher

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Should I have taken that piece off?!?

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Gotcha, that might be a new probe design then.

I don’t think so, but you should check with support or perhaps somebody else who’s received a newer unit will chime in on that.

The pH probe has a cap that should be taken off, as it is filled with fluid for transportation - but that’s the EC probe that was raised and it doesn’t usually have a protective cap. I wouldn’t remove it unless somebody tells you to.

Or is that just the lid-section of a protective cap that was on it? If that’s the case it probably slides right off, yeah.

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That is your problem, yes slide it off and insert it into the slot properly. Great eye @vegetato

After you’ve done so, then run your drain fill and the Grobo will correct you’re pH.


@SWSVIC that’s the EC probe that wasn’t lowered very far, but it was probably still contacting the water. That would’ve affected bottle #5 if anything, and I believe it would dose if the probe weren’t giving a reading (as opposed to not dosing).


You’re correct, my mistake. I do have newer unit and that cap did indeed slide off so that the meter could sit properly in its holster.

@Spencer can you post a picture of your nutrient bottles showing what has been dispensed.

These 2 caps were taken off initially