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Help with leaf color? Nitrogen deficient?

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Help with leaf color? Nitrogen deficient?

Jslo313 31 Replies 4,348 Views
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Jslo313

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#1
Third grow. First two didn’t go great. Lol. Moved this one downstairs where it’s a little cooler and away from smoky air. I let these grow without any nutes as it always seemed I was too heavy, even at half doses. I saw what I anticipated being a slight nitrogen deficiency so I added a half dose of cal/mag and a half dose of veg fertilizer. Have them four days to recover and took some pics. Y’all think these leaves still look like they could use a bit more nitrogen or am I not noticing a different deficiency? Or am I just being paranoid and they look fine? I’m a complete nutrient noob!
 
#2
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#3
Hello and welcome to the forum.
So lets see some pictures of your setup.
How old are these plants? pot size?
What grow light do you have. What power setting.
How high above the top of your plants.
What potting medium are your plants potted in?
What fertilizer are you using? How much?

Do you have a
PH pen
EC pen
PPM pen.

Any what what ever you can add will help us help you.
Any questions, don't be shy - fire away.
Will check back a little later.
Ron
 
#4
2x4 tent. Day 60 (from planting after germ) of the grow. 100w LED light. I’d say 20 inches above plants. water has always pen ph’d to 6.5-7.0. No flushing yet as I’ve only JUST added a touch of nutes. 3gallon pots. Soil is 75/24 soil to coco mix. King’s mix soil. Haven’t paid a lot of attention to Pom but I’ve been using straight RO water every other watering (every four days approximately) and every other watering I mix half RO half tap. Water isn’t hard or super chlorinated or anything but I forget the exact measurements.
 
#5
It's best if you off gas your tap water as there is a lot of minerals in it that your plant gets that are no longer in R.O water.
It helps.

Yes I'd say that the pre-amended soil is running out of gas.
What do you have for nutrients?
Maybe see if you can keep the PH down just a little 6.5-6.8
 
#6
Sorry, wasn’t sure what you meant by off gas the tap water but yeah I add a half gallon every other water just to get the micro nutrients. Just lemme now if y’all recommend I do every watering that way. Save me a coupla bucks a week. Lol.

As far as PH, previous grows, runoff was measuring in the low 5’s and heavy on the ppm, that’s why I’m allowing a slightly higher ph and using a little less tap water. If that’s a dumb way to solve the problem, please advise! Lol

Nutrient line is fox farms. Using the Grow Big right now and I believe it may be tiger bloom for flower. Thinking i might still let it veg another week or two and let the offshoots catch up to the mains a bit. Trimming day is Saturday (today) so I’ll be removing anything below the net. Net is pretty full so I’ll be switching to flower soon.

Main issue though, do y’all think the color is nitrogen deficiency? And should I add a bit more nitro nutes? Or just stick to a regular feeding and keep up with the half recommended doses and maybe add a bit more tap water during feedings?
 
#7
Correct me if I’m wrong but the lighter green is just newer growth? I’m new also so don’t use my input. (I see a magnesium deficiency with my eyes but that could be a million other reasons). Hope you get it taken care of. They look pretty.
 
#8
Thanks. I was thinking maybe magnesium as well but I’m still in that phase of learning as well. Lol. I did a half dose of cal mag with that last watering.

It is kinda limited to the new growth but I’ve got some older leaves yellowing as well so was just hoping for a trained eye to be like “it’s this!”. But maybe that’s not so common when diagnosing living things! Lol.
 
#9
Jslo313 said:
Thanks. I was thinking maybe magnesium as well but I’m still in that phase of learning as well. Lol. I did a half dose of cal mag with that last watering.

It is kinda limited to the new growth but I’ve got some older leaves yellowing as well so was just hoping for a trained eye to be like “it’s this!”. But maybe that’s not so common when diagnosing living things! Lol.
Click to expand...

I know zero about ro water. I know mag deficiency because I just got over it(am getting over it). I just left it alone and made sure my ph is right, it’s recovering. May be time for a new ph pen
 
#10
Off gas water. Chlorine is a gas. If you fill a bucket with water the chlorine will come out of the water in it's gas state / off gas.
A 20 L bucket will off gas in 24 hours or so at room temp.

I'm,thinking your on target with nitrogen deficiency.
15ml or 1 tablespoon per gallon should net you 220 PPM (N) per gallon of water. Witch is about right.
What have you been giving her?

I'd like to see a little extra phosphorus as well
A snort of a bloom booster like 0-50 -30 would not hurt to clean up the red stems.

Can you tell me what light you have? I'm thinking you may be a little close as well.
I have a little Led draws 120W 300w output. Even it's 18" You must have a 1,0000
and should be 28- 30 inches above the canopy.

This will change your life!
Make a log book and graph it as shown.
Grab a pen a peace of paper and a calculator. Learn how to do this.


Then this.
 
Last edited:
#13
Interesting video. Thank god I play Factorio. This isn’t half as complicated as five rockets per minute! Also, “high value” crops. This guy is growin the ganja on the super down-low! Lol.

Two questions and I bet I could look this up on my own but curious as to your thoughts, is cannabis in veg looking for 250 ppm? I could be remembering wrong but I had watched a video saying 750 was about the sweet spot. Maybe that’s a different stage or maybe that guy was a quack. Guess I’m gonna have to figure out what my tap is gonna add ppm-wise and then start thinking about nutes. If I’m going 250 ppm in the future, should I be looking to add that during every watering or still every other watering?

Also, yes some of the larger/older fan leaves have brown spots. Will post pics in the morning.

Measured distance of light. 24”. I raised them just a touch to about 26 but I’m gettin close to the roof. Lol. I think it maybe coming close to flip time just so I don’t run out of space.
 
#14
Choppr said:
Yellow on new growth top of the Plant...how wet are your pots.?
Click to expand...
Not very wet. Been throwing a gallon into two 3gal fabric pots. The bottom gets moist but but never dripping wet.

What would you say the yellow new growth has to do with water levels? Asking cuz I don’t know squat about squat. Lol.
 
#15
When you flip them they will grow into the lights big time.

If you google Cannabis ppm. It comes up with some ridiculous number like that.700 and 1400 ppm. My question was, of what? And I could never seem to get a proper answer.This is why I went looking for the information in this video, And it took me a very long time digging threw the chaff to find.
But in the end it's worth the time invested.

Is cannabis in veg looking for 250?
The answer is a large plant on a full sun day mid summer sure. A large plant under a 1000w light, it is entirely possible. But!
The amount of water uptake buy a plant is directly proportional to the amount of light it is receiving at any given time!

Lets say a plant has been watered well with a solution containing 250ppm of Nitrogen. The plant uptakes the water and the 250ppm nitrogen with the water. It cannot take 100ppm N if the sun is not shining today. It may only take up 1/2 the water but it gets the nutrients at what ever level are in the ground / solution.

So today you give the plant 4 liters of 250ppm solution. The sun is out and the plant takes up all the water. Great.
Tomorrow. You give the plant 250ppm N and the sun only shines 1/2 the time. The plant takes up 1/2 the water and nutrients.
The next day you feed again. You end up with a buildup of nitrogen /salts in the potting medium.

This is what causes burned tips. An exes of nutrients in the medium. If you watch the second video he shows you how to
use an EC meter to look at the percentage of solids in your solution before you put it in the top. Then capture the runoff
and use the EC meter to calculate the difference between what you put in the top and what ran out the bottom.
Then you can adjust your input ppm so that your never in a state of more coming out the bottom than going in the top.

Now it's time to lay another video on you. About 99% of the math goes right over my head. But you will understand enough
to get your sorted. His medium recipe is great. I use it indoors, but you will find 50% peat 25% Perlite and 25% Vermiculite works very well
and it helps to keep the cost down. Add the 40 Grams of Lime and 10 Grams of Gypsum pr gallon!

You water this like it's hydroponic. Every watering 100ppm (N) and you water until 10% that acts as a flush that keeps any extra nutrients from building up and use the runoff and measure the ins and outs.
It's a bit of a pain to graff it but it works!
 
#16
Without knowing all the details, I would say your plants just need a good feed with all the micros and macros. Don't worry about which ones, the liquid nutrients are balanced and have them all. Plants are deficient from not getting enough food and water. In the fox farm line big bloom is going to be your best friend. Also your basically in a coco mix at this point so I would treat it more like one. using R/O water only - Mix up 4-5ml/gal cal-mag, 5ml/gal grow big, and 15ml/gal big bloom - pH to 6.2, EC should be like 1.2-1.3 and give them each 1-2 gallons, just soak them with a bunch of runoff, they need the food and pH set. If EC comes in low, add a little more grow big to bring it up. Honestly though, for coco/soil grow id use botanicare pure blend pro grow. Then alternate between that feed and just plain r/o water with 4ml cal-mag and some great white at like a 6.5 pH. When you hit bloom, just switch the grow big to tiger bloom and each week raise your EC with tiger bloom by .1 until you hit 1.8 at week 5, then back down .2 each week so week 7 is at 1.4 then flush. Back off on nutrient strength if your getting dark green leaves, burnt tips, and/or crusty leaves. Pull the calmag out by week 7. Get10-20% runoff each watering and don't let the pots dry out. I'd be watering every day or every other day. There are definitely some other nutrient additives out there like liquid karma, silica, and vitamino that will help you out too.
 
#17
I would have to agree with this. Sorry I have gotten a little side tracked. As I do not use any commercial cannabis liquid fertilizers like the fox farm lineup It's pretty hard for me to throw out hard numbers like this. Thank you Comnconnection!
 
#18
Imzzaudae said:
I would have to agree with this. Sorry I have gotten a little side tracked. As I do not use any commercial cannabis liquid fertilizers like the fox farm lineup It's pretty hard for me to throw out hard numbers like this. Thank you Comnconnection!
Click to expand...
I liked that info you posted too 🤙
 
#19
Jslo313 said:
Third grow. First two didn’t go great. Lol. Moved this one downstairs where it’s a little cooler and away from smoky air. I let these grow without any nutes as it always seemed I was too heavy, even at half doses. I saw what I anticipated being a slight nitrogen deficiency so I added a half dose of cal/mag and a half dose of veg fertilizer. Have them four days to recover and took some pics. Y’all think these leaves still look like they could use a bit more nitrogen or am I not noticing a different deficiency? Or am I just being paranoid and they look fine? I’m a complete nutrient noob!
Click to expand...
Check out “build a soil” this is the way 🙏
 
#20
Flush...raise light 3"...possibly repot but probably won't be necessary if you can keep the soil a tiny bit warmer...this is a combination of high pH. Most likely suffocated roots as well...due to insufficient aeration, these things working together causes an inability to break down calcium and magnesium...thus other important nutrients (your n,p and ok) become much harder to uptake by the plant. Good luck soldier 🪖🫡
 
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