Update: still have nutrient deficiency, brown spots on leaves


  • Tip burn on lower leaves with the brown spots.

  • Brown spots have extended up into 2nd node leaves.

  • Need to correct the nutrient issue.

  • Root issue appears to be resolved.

  • Discoloration on the roots is from the nutrients.

  • Pinkish color was splashed underneath the lid.

  • Dried top of Cocoa pod. Is it ok that the lower portion where roots are is wet?

  • Possible bacterial issue was starting, blackish/brownish stuff on probe tips and plate with nutrient tubes.

  • Drained water, cleaned the best I could on the inside.

  • Cleaned and calibrated probes.

  • Added .5ml hydroguard

  • Bacterial problem is resolved, no root rot.

Water temp issue

  • Temp is running too low, 55 degrees without intentional cooling. Recalibrating thermometer and checking again.

  • If this is correct, how can I elevate water temp immediately?

  • Air temp 76.5

  • Humidity 43.0

  • pH 6.0

  • Water 55.0

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Contact support, it’s probably a cal-mag deficiency. @Stephen can manually add more.

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I sent a support request a few hours ago but did not receive a response yet. I am going out of town tomorrow night so I would really like to resolve as soon as possible. Thank you for responding.!

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I find it very strange your water temperature is 55F and your inside Grobo temp is above normal room temp (76F)

I’ve had my grow going for over three weeks and my water temp is almost always 4 to 5 degrees lower than the temp inside the unit… That seems strange to me.

My inside temps have ranged from 70 to 78 in the past two weeks for the most part, and the water temp correlates in the same way from 68 to 73. When it was hot outside in the first germination period, my inside temps were like 83 and water temp was up to 76.

Faulty water thermometer? I’m curious how you can calibrate it properly without having another one to compare to? Just wondering if you had done the calibration yet?

Sit tight, I just read in another thread that @Dani is off for her birthday, and Stephen is answering emails as he gets to them, little behind… I guarantee you’ll have a response tomorrow if not tonight.

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I cleaned and calibrated a new Bluelab and got that reading of 55. I felt it was inaccurate as well. The room temperature is typically around 70-72 degrees. I have another thermometer coming from Amazon today so I have something to compare it to. Would you happen to know if a digital meat thermometer would work?

Seems very weird because the heat of the growlight eventually heats the box up and it would seem very strange that the water wouldn’t heat up as well in time, cuz it sure does in mine it seems like, especially in accordance to how hot my room is.

I think the one from Amazon will definitely give you a clearer picture.

Did you possibly fill your Grobo with really cold water? Like out of the fridge, which would typically be around 41F give or take…I have no experience there but if that was the case then I would imagine it would take a lot more heat energy to warm that water up and more time.

I would say clean the meat thermometer off real good with alcohol and give it a try. If it’s digital it will get a pretty fast reading, might not be 100% accurate for water but will definitely give you a temp…if it reads anything closer to 70-72 then I’d say your Bluelab one is messed up. If it’s telling you a number in the 50’s then maybe your water really is just that cold… but again I find that really hard to believe.

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P.S. Looking at your #5 bottle I think maybe it looks a little too high, @VermontGrobo is that why you said something about the Cal/Mag ? As well as the rust colored leaves too

I’m just learning but my #5 is getting lower and lower, it’s the most used bottle so far.

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This is from this morning.
pH 5.7
H2O temp per meat thermometer 68.0 (bluelab one does not work)
Air temp 77.7
Humitity 43.2%

Need to correct this deficiency before I leave this afternoon for vacation. Hopefully Danielle is available to help. Thanks!

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I used the meat thermometer and it read 68. I am not sure how accurate it is but it is at least within normal range now. I am more concerned about then nutrient issue that is progressing. If I am unable to add anything I need Grobo to adjust as soon as possible. I leave town today. I have attached today’s photos for you to review. Thank you so much for your help!

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Also, if you are wondering why I have flowers on the caps to the nutrients it is because they came with 2 holes and were defective. Those happen to be in my craft drawer and fit perfectly. I still need to reach out to Grobo for a new set of caps.

Today’s stats and photos. Need help a.s.a.p. I am leaving town for a few days and my boyfriend will need to handle this for me. Thanks!

Water temp 68.0 per meat thermometer, bluelab is defective, waiting on new one.
Air temp 77.7
Humidity 43.2%
pH 5.7

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Hey grower! I know it can be a bit nerve racking on the first grow, especially if you start to notice leaf discoloration or something that may need attention. But I think your plant is doing quite fine.

It is not unusual to have some slight discoloration on the leaves. How is the new leaf growth near the top of the plant? Looks healthy to me. Also, any leaf discoloration generally will not “restore” to a healthy green color, it will stay the same or get worse looking. Follow-up with support and see what they think.

Bottles look ok, seems to be dispensing from all 5. In regards to the two holes in each cap, I believe they were purposefully designed that way. One hole for the tube and the other hole acts as a vent.

Hang in there! These plants are very resilient!

I would recommend a WYZE 1080p camera for $25 so you can remotely view her, like this:

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Is #5 a pinkish color once dispersed? That is the color that was on the roots and still splashing on underside of the lid. Right now the pH is also on the low side and should probably be increased.

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Yes the liquid in Bottle #5 looks kinda reddish/pinkish and may discolor the roots and underside of the lid. pH is monitored hourly and should be managed by the machine. I think it’s within range.

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That’s funny you say that because I ordered a WYZE last night! The reason I feel it is a nutrient issue is because of the brownish copper spots that seem to be progressing up so I just want to be sure. I agree, the top is looking healthy.

Question on caps though. All grobo videos show 1 hole only. Should I be venting these bottles? I assumed that was defect and opens up room for contaminants to get in the bottle.

Thanks for your help!

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I assumed everything was controlled by Grobo as well. So far it’s a little more maintenance than I anticipated but I don’t mind. It is a good learning experience for my grow tent hydro I will be starting soon. Knowledge is Power!

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They used to have a pin hole, but that would get clogged sometimes - so the hole was made larger, that’s all.


You’re welcome! You’re right, earlier videos of the Grobo show the bottle caps with 1 hole. They definitely made 2 holes on purpose though. A vent is needed but there’s probably enough of a gap between the drilled hole & tubing that enough air is allowed to pass thru to not create a problem.

Check out my Lamb’s Bread plant, it had quite a nutrient deficiency and she’s still going along and will make it to harvest. Granted she doesn’t look too great with all the orange rust spots but she’s maturing just fine.

Again, you can’t undo the leaf discoloration but use it as an indication that something is off and needs attention. Looks like you are handling it really well by contacting support and keeping an eye on her.

When was your last drain/fill? Were you able to confirm bottles 3-5 dispensed? It helps to mark the bottles at each liquid level so you can keep track.

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I just did a drain and fill on Fri so I am not due quite yet. But thank you for the tip on marking the bottles and the caps!

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