Yellowing leaves help

W

whoisami

New Member
Hi all. I am about 3 weeks into my first cannabis grow. About 1 week ago, one of the plants started developing yellow leaves. I initially thought it was likely related to flowering, however it is beginning to seem more systemic. The plants are in a 4x4 tent with x4 LM301H panels. I feed everyother day with peak harvest grow and bloom nutes, with liquid bone meal every other feed, and yucca extract. Growing in soil with ph of 7ish.

Based on what I've seen online I am curious if it could be a magneisum or potassium deficieny. Some plants do have a bit of a red stem which I read could be related to low nitrogen. But, I am very new to growing as I mentioned earlier, so I would love any feedback! I was feeling pretty good about my first grow but this is prettty discouraging.

Thanks in advanced!
 

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whoisami said:
Promix
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Promix what? Any Promix I've ever used is inert peat-based. If that's the case, then you are pH-ing too high. 5.7-6.3 for peat.

"7-ish" isn't good enough if you want reliability. Improper pH can lead to all sorts of issues, including the possibility that you may take the problems as deficiencies, start adding more nutrients to fix it, only to find that a pH imbalance was causing lockout, and now you've completely poisoned the plants by over fertilizing.

Stabilize the pH, wait a few feeds, then reassess the situation.
 
spek9 said:
Promix what? Any Promix I've ever used is inert peat-based. If that's the case, then you are pH-ing too high. 5.7-6.3 for peat.

"7-ish" isn't good enough if you want reliability. Improper pH can lead to all sorts of issues, including the possibility that you may take the problems as deficiencies, start adding more nutrients to fix it, only to find that a pH imbalance was causing lockout, and now you've completely poisoned the plants by over fertilizing.

Stabilize the pH, wait a few feeds, then reassess the situation.
Click to expand...
What is the best way to bring the ph to 5.7-6.3? I water with water that has a ph of 6.8. Should I lower the water ph to bring down the soil ph?
Thanks for your help!
 
whoisami said:
What is the best way to bring the ph to 5.7-6.3? I water with water that has a ph of 6.8. Should I lower the water ph to bring down the soil ph?
Thanks for your help!
Click to expand...

First, you didn't answer as to what type of Promix you're using. They may just make actual soil (not peat) that I'm unaware of. We need to know what medium you have, because pH must be aligned with the medium.

I use citric acid (powder) to bring down pH. The majority of growers it seems use General Hydroponics pH Down (it's a combination of both Phosphorus and citric acid).
 
spek9 said:
First, you didn't answer as to what type of Promix you're using. They may just make actual soil (not peat) that I'm unaware of. We need to know what medium you have, because pH must be aligned with the medium.

I use citric acid (powder) to bring down pH. The majority of growers it seems use General Hydroponics pH Down (it's a combination of both Phosphorus and citric acid).
Click to expand...
My apologies, I must've missed that. I am using Promix HP.

If I understand correctlyI could lower my water ph to around 6 to help off-set the alkaline soil?
 
whoisami said:
My apologies, I must've missed that. I am using Promix HP.

If I understand correctlyI could lower my water ph to around 6 to help off-set the alkaline soil?
Click to expand...

Promix HP is definitely peat-based. I used it for several years before switching to Sunshine #4 a while back.

You want to lower the pH of the water after you've mixed in all of your nutrients. 5.7-6.3 pH.
 
spek9 said:
Promix HP is definitely peat-based. I used it for several years before switching to Sunshine #4 a while back.

You want to lower the pH of the water after you've mixed in all of your nutrients. 5.7-6.3 pH.
Click to expand...
Great!
Thanks so much. I will try that for a few days before increasing nutes
 
whoisami said:
Great!
Thanks so much. I will try that for a few days before increasing nutes
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Don't remove any of the problematic leaves yet. Leave them in place so you can monitor whether the problem has stopped, or is spreading. The severely problematic leaves may not recover, so you're monitoring for the problem spreading or stopped only, and not for recovery. I recommend taking a photo or two every day, so that in a couple to few days, you can compare pictures to the plants directly, eliminating any guessing.
 
This thread has me thinking. I’ve never considered using anything other than 6.5-7 as my ph, and I use promix Hp ( mycorrhizae ). While I’ve never really experienced any toxicity or deficiencies, it has me wondering if maybe my plants aren’t receiving most of what I feed them which are my amendments, I don’t bottle feed. Other than water, I only feed guano, kelp, molasses, sometimes silica and Calmag. My ph drops to 6.0 when using these supplements, and I always “ ph up “ to 6.5. I think I’m going to try the 5.8-6 ph on one of my clones and see what happens.
 
spek9 said:
Don't remove any of the problematic leaves yet. Leave them in place so you can monitor whether the problem has stopped, or is spreading. The severely problematic leaves may not recover, so you're monitoring for the problem spreading or stopped only, and not for recovery. I recommend taking a photo or two every day, so that in a couple to few days, you can compare pictures to the plants directly, eliminating any guessing.
Click to expand...
That is a great idea. Thanks!
 
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