Please help diagnose

[Droopydroors]

So this is the third plant in a row that I have had this problem with. Here are the stats. I grow autos only.

800 true watts led
2:1 Coco loco / FFOF 15% perlite
Tap water pH at 6.5
Fox farms nutes at 1/2 strength - every other watering
Calmag at 1ml per gallon with nutes

I can not see any bugs anywhere. This problem seems to start once they start flowering. As I know the leaves will turn yellow and fall off when she gets further along in flower I am more concerned with the brown spots just popping up out of no where and then the leaves yellow and die. The last three plants were quite big for autos getting above the 2 ft mark. Any help would be great I'm just getting a little upset that this keeps happening.

IMG_20180618_001055196.jpg

• Droopydroors
• Jun 17, 2018

IMG_20180618_001008815_LL.jpg

• Droopydroors
• Jun 17, 2018

IMG_20180618_000956634_LL.jpg

• Droopydroors
• Jun 17, 2018

Thanks in advance

 

[Droopydroors]

I should also note my tap water is only 40 PPM so I don't think I'm getting any cal in the water. And I do let it sit out for 2 days before using.

 

[Ganjagrowergu]

You said tap water ph'd at 6.5. What is the pH after you add nutrients? My gut tells me it's a pH problem. When my plants have problems, it is almost always something to do with pH, but that is me.

Hopefully someone else more knowledgeable stops by. I don't work with soil at all anymore and am a bit rusty

 

[GrizzWald]

Quadruple your cal mag... Add cal mag to water before adding anything else..

 

[Droopydroors]

You said tap water ph'd at 6.5. What is the pH after you add nutrients? My gut tells me it's a pH problem. When my plants have problems, it is almost always something to do with pH, but that is me.

Hopefully someone else more knowledgeable stops by. I don't work with soil at all anymore and am a bit rusty

I'm sorry I should have been more clear. The water is 7.4 out of the tap. After adding nutes it's down around 5.4. I add around 1/2 tsp of pH up to get it to 6.5.

 

[Droopydroors]

Quadruple your cal mag... Add cal mag to water before adding anything else..

So you are saying I should be using 4tsp of Calmag per gallon? And put it into my nutes feeding prior to putting in the flower nutes? Also should I be giving Calmag on every watering and feeding or just feeding? Thanks

 

[Droopydroors]

I'm sorry in the description it said 1ml I've been using 1tsp that was my mistake. Sorry.

 

[Ganjagrowergu]

I'm sorry I should have been more clear. The water is 7.4 out of the tap. After adding nutes it's down around 5.4. I add around 1/2 tsp of pH up to get it to 6.5.

Well, then I would try what grizzwald said.

 

[Calvados]

What kind of soil are you using?

 

[Droopydroors]

Like I said in the first post.

2:1 FF Coco Loco / FFOF with 15% perlite

 

[Calvados]

Like I said in the first post.

2:1 FF Coco Loco / FFOF with 15% perlite

Sorry, I missed that. FFOF is Ph'd from 6.3-6.8. I couldn't work out what FF Coco Loco is Ph'd at. I guess 6.5 is probably right for an adjustment.

 

[improvise]

Cannabis Plant and Pest Problem Solver - Pictorial regards

 

[Droopydroors]

Cannabis Plant and Pest Problem Solver - Pictorial regards

Ya I've looked through that already just can't figure out if it is low P or low Calmag they look alike. Also I'm trying to figure out how much Calmag I should be feeding since I am under led. So should I feed Calmag every feeding and watering or just feeding. Thanks guys.

 

[GrizzWald]

Add cal_mag every watering...Up to 2ml litre cal-mag.... Dont feed your plant forever, they get sensitive late and just enjoy pH corrected water to the finish line... ...

 

[Justones]

Reminds me of a possible Phosphorus deficiency. Maybe Google some cannibis phosphorus deficiency images & see what you think. How far into flower are they in these pics?

 

[Droopydroors]

Reminds me of a possible Phosphorus deficiency. Maybe Google some cannibis phosphorus deficiency images & see what you think. How far into flower are they in these pics?

They are autos but I would say they are about a month out. I think it was Calmag shortage that was causing P to not get into the plant as needed. Also this plant is sooo much bigger than anything else I have grown so I think I wasn't giving her enough nutes. I did not know you have to add Calmag to the nutes mixture first and I also was not adding Calmag on days that I only watered. I'm glad I asked for help though because I will hit her with some extra Calmag over the next week or so and then start flushing. Hopefully I can correct the problem so the buds don't suffer more than they already have.

 

[GrizzWald]

All's good mate, flowers look healthy, she'll be fine... Want to make yourself feel good? Cut The crap off, all the fingers where the diff is showing.. she'll look and start feeling better and so will you, lol...

 

[Justones]

Ok, I'm curious how the extra calcium & magnesium works out for you. Post some others next week to share please. I just felt it was phosphorus because of two things. One it reminds me of that. And two because you said your only giving it half nutes.

But I also know some issues closely resemble other issues when just looking at leaves and pics.

Best of luck to you and the little lady there.

 

[Droopydroors]

Ok, I'm curious how the extra calcium & magnesium works out for you. Post some others next week to share please. I just felt it was phosphorus because of two things. One it reminds me of that. And two because you said your only giving it half nutes.

But I also know some issues closely resemble other issues when just looking at leaves and pics.

Best of luck to you and the little lady there.

Will do. The only reason I only go as high as half nutes is because I always read that autos don't react well to full strength nutes. So I'm always cautious even giving 1/2 strength. But when they get as big as she is I'm thinking it wouldn't hurt. I just have such a hard time telling the difference between P deficiency and excess in pictures. Both of them have burnt tips and both of them leave brown spots and then turn yellow. I'll get it figured out eventually.

 

[GrizzWald]

Half nute is more than enough.. too much on some...