Nutrient problem, a chronic problem, apperently.

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TheForechecker

TheForechecker

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Hey all, I started growing cannabis in Sept and love it. I am using soil and Gaia Green organic dry amendment nutes.

I had this same problem with my last (first) run of Critical mass (CM). The leaves at the top start to show interveinal yellowing. The CM did the same thing starting around flip to flower. I really abused those CM so much I'm just gonna let it go because it's impossible to troubleshoot a stew of nutes and other abuses on that run. This new batch, I've used the Gaia green 444/bloom at the correct times while using RO (alkalized with trace minerals). I've kept it pretty clean.

I can't figure out if its mag, cal, nitrogen deficiencies or phosphorus toxicity. I ph my water to 6.2-6.8. The last watering for this plant and another showing same, I added a teaspoon of Epson salt for mag, some molasses and sucanat sugar for the starting of bloom.

Any Ideas? Flooding them with nutes didn't work well last run, so id like to confirm what this is before I progress.

1. Are you growing from seed or clones? SEEDS
2. How old are your plants? DAY 15 FLO, 29 DAYS FROM START OF VEG
3. How tall are your plants? 2FT
4. What size containers are they planted in? 3GALLON
5. What is your soil mix? GAIA GREEN/PERALITE
6. How often do you water and what type of water do you use? ONCE EVERY 3 OR 4 DAYS, TO WITH TRACE MINERALS
7. What is the pH of your water? 6.2-6.8
8. What kind of fertilizer do you use and what is its NPK ratio? GAIA GREEN 444 AND BLOOM
9. Do you foliar feed or spray your plants with anything? NO
10. What kind of lights do you use and how many watts combined? 650W LED LIGHT BAR
11. How close are your lights to the plants? 18-24"
12. What size is your grow space in square feet?60FT
13. What is the temperature and humidity in your grow space? 80F/55% DAY 68F/55% LIGHTS OFF
14. What is the pH of the soil? NOT SURE
15. Have you noticed any insect activity in your grow space? FUNGUS GNATS
16. How much experience do you have growing? A LOT OF GROWING FOOD FOREST GARDEN EXPERIENCE, PLANTED MY FIRST CANNABIS PLANT IN SEPT 2020

Cheers!
 
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mysticepipedon

mysticepipedon

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Take the pH of a slurry of your soil. I'm betting it's a little on the high side, above 7. Weight out some soil — about 10 grams, and mix it with 20 ml of distilled or RO water. Let it sit for about 15 minutes and then take the pH.

This looks like classic iron and/or zinc deficiency, which is probably caused by a high soil pH.

It could also be some interaction in the soil, as your chart indicates.
 
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TheForechecker

TheForechecker

21
3
Take the pH of a slurry of your soil. I'm betting it's a little on the high side, above 7. Weight out some soil — about 10 grams, and mix it with 20 ml of distilled or RO water. Let it sit for about 15 minutes and then take the pH.

This looks like classic iron and/or zinc deficiency, which is probably caused by a high soil pH.

It could also be some interaction in the soil, as your chart indicates.

Ok, I did that with distilled water and its coming in at 7.4 and 7.5 on 2 different ph meters. Maybe its time to invest in a Bluelab soil PH tester, since I'm staying with living soil.

Thanks, this makes a lot more sense. Not a chronic nute problem, a chronic ph problem (and grower knowledge/experience deficiency haha). Its not very shocking, since we have hard and high PH water!

Now to search the remedy! I appreciate the answer.
 
mysticepipedon

mysticepipedon

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OK, it's definitely pH.

I have watered with pH 5.0 water to bring down the pH of my soil when I put in too much dolomite. The plants didn't seem to mind. Also, you may already do this, but water with a little molasses mixed in as your sugar feed for the microbes — it usually has some iron in it. It helped when I had this issue.
 
tobh

tobh

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Make sure to use the unsulphured black strap molasses specifically. And thank you for using the infirmary template! used to be a big thing around here, but it's not so popular anymore.
 
TheForechecker

TheForechecker

21
3
Make sure to use the unsulphured black strap molasses specifically. And thank you for using the infirmary template! used to be a big thing around here, but it's not so popular anymore.
NP, I would have had to type it all out anyways. 🤟

I watered it with 5.9 ph water a few hours ago, and then ran another flush of water through it. The runoff showed between 3000 and 4000 ppm. So, I supposed all I can do now is wait it out and leave it alone.
 

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