Yellowing and curling leaves. Coco-Coir CFL Closet Tent Grow.

[LeBourgeon]

Hello all. I'm new to posting on the forum, but have read quite a bit from others.


I'm a first time grower. I am growing 1-2 plants in a small grow tent for personal medical use.


Here's my setup:


200w CFL (3:1 6500K:2700K)
16/8 light schedule
30”x18”x36” Milliard Grow Tent


400cfm 6” Hydrofarm Inline (Using custom-wired no-hum capacitance fan speed controller)
Passive Intake through ports
200mm PC fan that blows over lights.
Custom carbon scrubber


Tap Water: ultra high 450 ppm. Hydrated coco with this water.
Switched to RO after testing ppm of tap. Haven't tested the ppm of RO yet. pH ~5.5


(2) Sweet Seeds Dark Devil Autoflower.
Fox Farms Liquid Nutrient Trio Soil Formula
3:1 Coco Coirerlite
68-89 *F RH: 40-69%
3 gal pots with integrated drip pan underneath.


Watering schedule: Day 1:Tap water saturation of coco. Day 11: Pure RO (no pH) Day 13: 1 L RO with ¼ strength big bloom.


Photos taken 21 days after germination.


Symptoms: Drooping.Yellowing of leaves. Spiral curling of leaves. Purpling of leaves near stem.


If I had to guess, I would think that a combination of overwatering, nutrient burn, low humidity, and using extremely high PPM water are to blame. The purple color and spiral curling are from nutrient burn and (dissolved salt excess?). The overwatering caused the drooping and yellowing.


I am running the lights about 3-4 inches away from the leaves. And only about half are on. Otherwise, temperature builds up in cabin quickly to 92 *F.


Any and all advice is appreciated. Thank you!





DD1
>
DD2 (Planted on Day 6)

Cabin


I'm not sure why photos turned out sideways. Any suggestions?

 

[Muddy]

Welcome to AFN. The purple stems and leaf curling aren't symptoms of over feeding. Given that you are growing Dark Devil, the purple stems are most likely genetic. If anything, I would say they are underfed. Coco is a soil less medium and contains no nutrients, so it's up to you to supply everything the plant needs. If I'm reading correctly you've only given them one feeding and that was at day 13 and it was bloom nutrients. At this point, and until vertical growth stops around week 5-6 you should be feeding them veg nutes, Grow Big. I would suggest that you follow the Fox Farms feeding schedule, only at half their recommended strength. Also, since you are now using RO water, you should be adding a calcium/magnesium supplement. RO strips all the minerals from the water so they need to be replaced.

Take a look at this thread, it should give you a better idea of what to expect from your plants: https://www.autoflower.org/f44/life-cycle-auto-flowering-cannabis-5113.html

 

[medic grower]

Also i would consider to switch to Coco Nutes. Im growing on Coco since gd 7 years now. And in my start Times i also used my Soil Nutes for Coco. Ended up in Yellowing Plants.

 

[Happy Horticulturist]

When did you start feeding nutes? At day 13? If so then there's your problem!

Personally in coco I start feeding extremely light nutes from day 1 and I gradually gradually increase them slightly each and every feeding. You want to very slowly increase the pressure in the plant until it's going dark green, then you wanna back off ever so slightly for a few days, then push it ever so slightly again.

Also definitely use coco specific nutrients and if you're using RO water you probably want to think about having a bottle of Cal/Mag on hand because RO water completely strips the calcium and magnesium from water, which generally has a lot of the stuff in it. Which when you combine that with coco which is a calcium hungry sonuvabitch medium to grow in (but a beautiful and awesome medium all the same) you really should be possibly topping your RO water up to 0.3 EC of Cal/Mag and then adding your 1/4 or half strength nutes.

EDIT: Also dude you're totally going to have to do something about your intake and extraction. That temperature is way too high and you're going to need a lot more light than what you have now if you want to grow good buds. Biggest newbie mistake in my opinion is under estimating how much airflow (and new fresh air) indoor plants need. Think about plants outside... now you have to recreate that exact same environment. Lots of light. Lots of airflow. You want your air temps to be 82f (27c) maximum! Yes the plants will survive with higher temps but your bud quality and over all harvest weight will suffer big time.

Good luck bro

 

[GoAuto6]

I went through this my last coco grow,

I beleive it was due to ph as the ph of me coco was up to to 6.3 to 7......

I lost these but still pulled off a couple others fighting ph the whole way Had to water and feed at 9+ !!!

GoAuto and The Virgin CoCo Grow.........

 

[Happy Horticulturist]

Yea coco really needs to be 5.8 - 6.0. Also it needs to be kept moist at all times. I find coco with LOTS of perlite mixed in works really well.

EDIT: Feed it small amounts and often (preferably a drip system)

 

[LeBourgeon]

Thank you all for the advice. It has been very helpful and constructive.

I was intrigued to learn that a lot of you experienced similar issues with using non coco specific nutrients. Other than (I assume) cal/mag supplementation, I would be curious to know what is different about their formulation.

I upped the fan speed for more airflow. And turned on the full 200w.

I had a few questions:

1. Is light tightness an issue with autoflowers? My tent is NOT very light tight. I tried foil taping the seams on the inside, but theres still some light that leaks out (especially from non-light-trapped intake vents).

2. Would switching the lights to night time be a good idea? I live in coastal California where temps can be high during day and low during night. If I switched it, I believe it would help bring the cabin temperatures down.

3. Ventilation. How should I configure the intakes? (Especially IF it supposed to be light tight?)

4. Is raising humidity crucial? Should I bother with getting a cheap humidifier or a clear plastic dome to put over the plants?

5. What do you guys think of soil moisture monitors? Are they a waste of money?

6. Watering. Do you thoroughly saturate the 3 gal pot or just pour near the plants (for seedlings)? And how often? Could someone please provide a link to an example watering schedule for coco.

7. For the feeding schedule, I'm supposed to use the SOIL version as opposed to Hydroponic one, correct? I realize coco is somewhat between the two. And I am using "soil nutrients."

8. Water selection. Given that I have tap water with 450 ppm, and access to RO, and Carbon-filtered water (haven't checked ppm of this yet), which water would you use? Is this tap too hard for seedlings? And the RO appears to require supplementary calcium/magnesium. Is the carbon filtered a happy medium?

 

[GoAuto6]

Just remember what you feed how you feed and how much you use won't matter if your ph is out of wack, it's a lock out at this point.......So I suggest a good probe like the accurate 8.

 

[Happy Horticulturist]

1. Is light tightness an issue with autoflowers? My tent is NOT very light tight. I tried foil taping the seams on the inside, but theres still some light that leaks out (especially from non-light-trapped intake vents).
I think with AutoFlowering plants this is not really important... I could be wrong but I think you'll be fine and it's the least of your worries right now

2. Would switching the lights to night time be a good idea? I live in coastal California where temps can be high during day and low during night. If I switched it, I believe it would help bring the cabin temperatures down.
Yes this is a good idea. You want to have pretty much the same temperatures and humidity during day and night to reduce chances of mold and mildew. Also you want your temps to never really get about 27c or about 80f

3. Ventilation. How should I configure the intakes? (Especially IF it supposed to be light tight?)
You want the intake and outtake to be as far apart as possible. So for example intake in bottom left corner (or bottom right) and out take would then in top right corner (or top left if intake is in bottom right.)

4. Is raising humidity crucial? Should I bother with getting a cheap humidifier or a clear plastic dome to put over the plants?
If your humidity is lower than say.. 45% it would be good to increase it. If your humidity is lower than say .. 30% than yes definitely you want to increase it. I would tend to stay away from humidity domes as that can raise the humidity too high. You really only need humidity domes for cuttings.

5. What do you guys think of soil moisture monitors? Are they a waste of money?
Yes, I think they're a waste of money. Best too add lots of perlite to the soil and water small amounts but often. (don't worry about adding perlite now, but next grow, definitely add some. I like about 30% perlite.)

6. Watering. Do you thoroughly saturate the 3 gal pot or just pour near the plants (for seedlings)? And how often? Could someone please provide a link to an example watering schedule for coco.
For coco you want to keep the entire medium equally moist all of the time. You never want it to go dry otherwise it's easy for coco to have salts form in it, which isn't good. It's easy to get coco to be equally moist because coco wicks so well. All you really have to do is pour water into it and given enough time the water naturally spreads equally throughout the coco. As above, add perlite to your coco mixture (with coco actually you can go higher, anywhere from 30-50% perlite) and water little but often! Keep that baby moist!

7. For the feeding schedule, I'm supposed to use the SOIL version as opposed to Hydroponic one, correct? I realize coco is somewhat between the two. And I am using "soil nutrients."
I dunno at all.. we don't get it in Europe. You can use 'soil' nutes in coco but it's not the best. Get coco nutes as soon as you can and follow their feeding schedule. That's all i can really say.

8. Water selection. Given that I have tap water with 450 ppm, and access to RO, and Carbon-filtered water (haven't checked ppm of this yet), which water would you use? Is this tap too hard for seedlings? And the RO appears to require supplementary calcium/magnesium. Is the carbon filtered a happy medium?
I have experience with coco and RO water and all I can say is have a bottle of Cal/Mag handy!! If you are going to use coco and RO water then definitely use coco specific nutrients. Coco is calcium hungry! Especially in the beginning, then it starts to release it's calcium. For now you could make 50/50 RO water and tap water. Or even 30% tap and 70% coco.