5 grows. Same issue every time.

Spunions

Member
I have been struggling to figure out what is causing this ever since I started growing. It has occurred every grow. 5 so far. I make it through veg with nice happy healthy plants, switch to flower and within 2-3 weeks these spots start developing. Typically on lower fan leaves first until eventually it starts going after sugar leaves. All but one of my harvests have produced good smoke, but I suspect my yields are suffering. And the plants are clearly stressed.

I grow in coco. I have used soil once and still had this issue. I started with foxfarms nutes then switched to GH flora series. I just use the basic three part. Although I add cal mag due to this looking like a calcium deficiency. I originally used nutes at the full recommended strength. At some point I cut that in half and have noticed no change whatsoever in the plants. I have a 2x4 growing area with a 4" intake and a 4" exhaust fan. 2 blower fans, one pointed at the lights to help with their passive cooling and another at the plants for air circulation. I am indoors, so climate controlled. 65 at night, it gets around 75 in the grow room with the lights on. I water daily with nutes in every watering. I check runoff and adjust the pH of my input to be between 5.5 and 6.5 depending on what the runoff was at the day before. I am using a total of 350w LED lights actual draw. I thought it may be too much light so I raised them and turn it all down to 50% intensity a week ago. I run a dehumidifier in the room and the humidity stays right at a constant 50%. i have also switched at some point from blurples to full spectrum lighting.

So I have checked temp, humidity, light, ph, watering frequency, and airflow. I am completely stumped.

For what it's worth I grow outside each summer using the exact same medium, watering technique, ph, and fertilizer, and I don't have this problem. It is something specific to the grow room. Any help would be incredibly appreciated. I can't figure out what I am missing.
 

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Wastei

Well-Known Member
That looks like a pH related problem? How often and at what strength do you feed? How do you check your runoff?

If you let the pots sit in runoff water you might have salt buildup problem. 5.5 pH on the input will most often cause problems growing coco coir. I most often need to run ~pH 7.0 in late flower. I raise pH when I see Ca related problems.

Cheers!
 

DanKiller

Well-Known Member
My bet is on too much nutes... Your ratios is causing a toxicity in the medium
Your new growth is super green so your N is too high probably messing with your Ca...
When you grow weed your not supposed to treat it like a special plant it's just weed, you seem to over think this too much
Never point your fans directly at the plants
Raise your lights on temps to 80+
Any lower than this you'll have metabolism problems and nutrient uptake problems
Don't mess with ph too much, coco will balance to what you give it so adjust to 6.1 ph on every watering and be done with it
If you give enough water to saturate the coco it will be in your desired pH within 2-3 waterings
Only give nutes in every watering if you can read plants and see what they want or very low doses
Especially in coco, you can mess things pretty quick
 

Spunions

Member
Thank you all for your responses. I am more inclined to agree with the too much nutes guess than the ph guess. I have been quite adamant about testing and adjusting the ph that it really can't be far enough out of wack to cause these issues. My cheap ebay TDS meter crapped out. So I am totally guessing on nutes. I also suspected that was a problem so I cut my use in half for this grow. Does half of the GH flora reccomend amounts sound like too much for each watering? Also if that is the case, any guess as to why my outdoor plants didn't mind even twice that amount?
 

DanKiller

Well-Known Member
It's not about enough or not, each plant had it's own tolerance and requirements
If you over do it they will all suffer even if some are more able to coup with it
Outdoor, metabolism is much better and faster due to temps and rh and also light qtys
Plants are able to process and live sort of speak better.

Look at your plants, not charts or recommendations, that's the only way you'll know when, how and why
In nutes, the golden rule is less is more.
 

Spunions

Member
Based on all of the responses I am going to reduce nutrients by half again to feed 1/4 strength (of bottle recommendation). I will stabilize input ph to 6.0 and see what happens. Thanks again for the responses. I don't know how to tell what my plants need by looking at them. I don't have much of a choice but to follow a guide of some sort and go from there.
 

DanKiller

Well-Known Member
Don't mess around with cal mag and nutes, if you don't know how to read plants how come you add stuff (such as cal mag)... It's not wise to speculate, apply, and slowly make things even worse..
If you grow in straight coco, you can't really let go of nutes... If it's a mix, go with ph tap water for now
Go as low as you can for now on the nutes if your in straight coco until they start to thrive and look happy..
 

coreywebster

Well-Known Member
A number of things all mentioned already are great points.

So as Mick said, worry about the ph going in, coco will buffer itself, don't measure ph coming out and try and alter it.

As Nutty said, 75f is low for vegging under LEDs and covered why.

Usually if you are over feeding you get a build up and that hits you about when your seeing problems, it's because your getting too much of one thing blocking another. Like p or k locking out Calcium..

It's beneficial to measure the EC of run off if you run into a problem, but if you can't then it doesn't hurt to assume it's high, flush with a light nutrient solution and then feed as normal, but not full strength, nobody really needs to be feeding 100% of the recommended dose, least not with most nutrients .
 

Nutty sKunK

Well-Known Member
I am curious if the CMH raised the temp to acceptable levels or just produces IR in sufficient quantity
Sure if you’re able to control the extraction. I’ve got a 630w DE dimmable light and easily keeps me 4x4 around 78f.

Also when I measured the leaf surface temp it was about 0.5f cooler than the room instead of 4/5f under LED.
 
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