New Grower New leaves are light green / yellow.

[Daramus]

Problem: New growth is light green / yellow

Medium: Mother Earth Coco Plus Perlite Mix (70% Coco)

Feed and supplements used: Dyna-Gro Foliage-Pro 9-3-6, Calimagic 1-0-0, Hand watered PPM lvl 300-500. I water about every 4 or 5 days, drain to waste.

water source: RO water with 40ppm, PH 6.5

Strain/age: Dwarf Low Flyer - Seedling emerged 7/24/20

light used: VIPARSPECTRA DS300 300W LED

Climate:Tent ranges from high 60’s at night to mid 70‘s during the day. RH 35-40%

Additional info: Been dealing with this issue for the entire grow. Seed was planted in 3 gal fabric pot and has never been transplanted. I used the coco straight out of the bag with no flushing or buffering.

Early on I worried that I had cal-mag issues since I did not flush or buffer the coco and I was seeing the yellowing. I added more cal-mag because I use both coco and RO water. The leaves seemed to darken over time but new growth stayed consistently lite green / yellow.

My runoff got to over 700ppm (i was overfeeding) and PH kept getting lower, eventually it got to the low 5s so I flushed it and things seemed to improve.

I just watered yesterday. Water has a base of 40 ppm, added calmag to 200 ppm then dyna-grow to get to 300 ppm total. I was doing 500 ppm but it was building up. Runoff ppm was around 450 and ph was about 6.2.

This is my second grow. My first grow was the same strain but I did not have this problem. Also by this time last grow I was well into pre-flower. No signs of flowers so far.

 

[Mañ'O'Green]

@Daramus Welcome to AFNYour girls look hungry to me.

RO water normally starts about 0 PPM so your membrane or EC Pen may be needing attention. Some meters do not work in RO. PH for coco should be 6.0. Coco should be fertigated every day or more often to run-off.

I was not using PPM/EC when I was growing with Dyna-Gro. The spreadsheet attached is what I used, it is in ml/gallon of water. You can change the strength percent and the volume you want to mix up and the sheet does the math.

Dyna Gro Autos DWC1.xlsx

Shared with Jumpshare

jmp.sh

 

[Mañ'O'Green]

Yeah I just looked up Mother Earth Coco perlite and no where does it say washed and pre-charged and if it is not you will have problems like this for sure. Do not worry so much about your run-off PPM you are not fertigating often enough for that to be valid. PPM total going in should be 750 by now.

 

[Daramus]

@Mañ'O'Green Thank you for the sheet and the advice

 

[Daramus]

Update. I have been feeding daily, slowing increasing PPM up to 850. Water is 50 ppm, calmag to 250 and the rest is Dyna-Grow Foliage pro. Plant doesn't seem stunted and has grown, however the light coloring still remains. This is supposed to be an autoflower and a DWARF so I am surprised at the amount of nutes it's taking. PH going in is 7.2 coming out about 6.4. Still no sign of flowering.

I included a pic under my blurple light where the discoloring is more pronounced. You can see other seedlings (different strain) that have normal shading. Both pics are of the same plant.

Should I keep increasing the nutes?

Edit: runoff PPM started off being slightly lower than incoming and is now about the same as what I'm putting in. Also, all the leaves have started off looking this way and then slowly darken up from the tips toward the center.

 

[Daramus]

After googling images with similar problems I ran across this thread:

http://www.thctalk.com/cannabis-forum/showthread.php?10441-New-growth-bright-yellow

I decided to flush this plant and see if that helps it to green up. I will update with pics for anyone who might be curious. I grew this strain earlier in the year and the plants never got taller than 18" since it is a dwarf. I flushed with 6 gallons and the last gallon was fed at 350 ppm.

 

[Daramus]

Here are some updated pics. Switched lights over to 12/12 and am starting to see flowering. I'm assuming I was sent a different strain by mistake. Color has always been light, but it does not seem to affect growth. Also have a non-blurple grow light now.