Turning light green

I’m currently on day 53 from seed on two white widow auto flowers from ILGM. One plant is looking really good and healthy with nice growth. The other has slower growth and has a lighter color. They are both in 3 gallon fabric pots with 80% happy frog and 20% perlite for the medium. After week 3 I started to use the fox farm trio big bloom and grow big at 1/2 strength. When I saw white pistols around week 5 I included tiger bloom. I’m running a viperspectra xp1000 led light that is currently 15” above tallest part of plants. One plant I’ve been feeding every other water and the other I feed every water since nutrients are a new thing for me and I wanted to experiment. I just checked my run off PH and one plant was 6.5 in and 6.4 out the other was 6.5 in and 6.3 out so I don’t think I have a PH issues in the medium. I usually water when the pot gets light and the soil is dry to my first knuckle. Since the medium PH is good I shouldn’t be experiencing lock out right? Could it be that the lighter colored plant is more hungry and needs more nutrients? I recently started to add cal mag in the last feed. I also used plain PH water on the last two watering of the plant that is lighter. Any advice would be great. Thank you.


Welcome to the community! Are you giving calmag, every watering, between feedings?

EDIT: just saw that you just started calmag. Use it every watering between feedings and she should even out. Calmag has nitrogen, which is what it looks like your plant is lacking.


What about the ppm of runoff?
This tells us more about if potential lock out or not rather then ph.
Have you followed ff recommend flushing schedule?

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A little about myself. Long time smoker. About 20 years ago I grew two runs in my closet under HPS and miracle grow with pretty good results. Fast forward to last spring I’m getting tired of paying for my smoke so I threw some bag seeds in miracle grow and put them outside. Pretty good results again but wasn’t a fan of caterpillars, rain and humidity. So now I want to try and do it right with some ILGM white widow autos, proper medium and nutrients. My issues pointed me towards Cal-Mag. It also made me realize I should check my run off PH from time to time. I’m not familiar with PPM though. How do I check PPM? I do have a digital TDS meter. Is that what I should use?
Thanks for answering and helping out.


It could be a iron deficiency

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Yep. TDS is Total dissolved solids, measured in PPM’s, parts per million. A lot of growers only check if they are showing issues, but it doesn’t hurt to check every now and again. Mainly want to have good numbers going in, and if you water til about 20% runoff, then usually issues are minimal.

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  1. Indoor or outdoor? - size of grow?
    Indoors 2 plants 2x2 tent
  2. Otigin of seeds?
  3. Regular, feminized, or autoflower?
  4. Origin of water. PH, EC/TDS of source water?
    Tap water. PH to 6.1-6.5
  5. PH and TDS/EC of if mixed solution?
    PH after mixing nutrients when added
  6. Grow method? Soil, Soil-less, Coco, Hydro, Aquaponics. Please explain.
    Soil FF Happy Frog 20% perlite
  7. Nutrients or fertilizer system used.
    Fox Farm Big Bloom, Grow Big and Tiger Bloom
  8. What typr of lighting are you using? LED, HID (MH, CMH, HPS), or Fluorescents? Please elaborate.
    LED Vioerspectra xp1000 running 18/6
  9. What are the temps in your growspce? Day / Night?
    Lights on 72-75 lights off 65-69
  10. What is the RH = relative humidity in your growspace? Day / Night?
    Lights on 37-42 lights off around the same
  11. AC, Humidifier, De-humidifier?
    Bowl of water and wet towel hanging to help humidity. Thermostat heater to keep temperature above 65 when lights off.
  12. Do you have a Ventilation system? Size? 4", 6"?
    4” ac infinity and vivosun scrubber
  13. Co2 Yes / No?
  14. How long have you been growing?
    Have grown 3 runs
  15. What budget have you set in order to grow successfully?
    Small budget
  16. If you grow hydro, then please explain your hydro method. DWC, R-DWC, Ebb and Flow, Or; Other? Other?
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Just started using Flying Skull Cal-Mag and it includes iron and B-1.

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Ok that’s exactly how I checked the run off PH. I watered the plant today with nutrients after I took the picture. The pot was light and I did the finger in the soil and it was dry even though I just watered with PH water it till run off on Friday. It looked hungry. That plant has more to it so it seems to want more water than the other one. I’ll get some batteries for the TPS meter and do another run off test when it’s time to water again in a day or two. So I should check the PPM going in and compare it coming out. There is no adjusting the PPM like I do with PH up and down right. Once I adjust the PH I’m good. I know you don’t want to see anything more then a .8 difference with the PH but what about the PPM?
Thanks again.


PPMs in runoff should be close to what you put in. If it’s way higher, then you have a potential lockout coming. If it’s way lower, then they’re probably hungry.

Say you feed at 900ppm for a few weeks and check runoff. If your runoff is way high, then there is potential for lockout, and plants will basically starve. If it’s way low, then you can probably up the feed. No need to adjust ppm going in, just pH


Aha ok wait and see how it goes

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So when I’m in soil (typically fox farm) for first month or so I don’t really worry about run off ppm/tds. I always ph of course going it.

But after plant has been in pot of soil for 4-5 weeks.
I then start checking ppm going in vs ppm coming out in run off.
This gives me an idea of how much minerals “plant food” is in the soil, or any medium for that matter…
I’ll know when to feed based of these numbers and how much to feed. .
For example, if I water with ph water with some calmag at 200ppm. If it’s week 5 in the pot if soil, say my run off is 1100ppm.
I know it’s not time to start my bottle nutrients yet but it is close. I would probably feed them a half strength veg mixture the next time I watered around 600ppm or so.

I use a desktop calendar to keep up with it easily.
If you use living soil and no added nutrients tds isn’t so important…
But if using synthetic nutrients keeping up with tds/ppm is a must really for a smooth run.

Here’s my calendar to give ya an idea and hopefully my wall of text makes sense :grin:


Thanks for explaining the PPM in more detail. I thought I would be ok just monitoring the PH.

You also asked if I was following FF flush schedule. Honestly I skipped past that at week 5. I find that topic to be confusing since there seems to be a lot of different opinions on when to use it, if at all. Some say to flush with sledgehammer only if showing signs that it needs it. Some say to follow the FF schedule. Some say it’s FF trying to make more money and just flush with PH water if needed.

Do you flush with sledgehammer? Do you follow the schedule? Have you experienced better results when using it?

Thanks for the help. Appreciate you taking the time.


So I should have been more specific sorry.
I don’t actually know alot about FF nutes. I use general hydroponics trio and cal-mag only.but I dont do all the add on stuff that is basically just so they make money. .

But I meant flushing with just plain ph water every so often but yeah no need to spend money on "flushing " products.
If you all ready got it then sure use it but i wouldn’t buy more.

The point of flushing when useing bottle nutrients is over time they can build up in the soil and literally overwhelme the roots and they can’t take up what they need leading to all sorts of issues…

By keeping track of ppm then you kinda know when to flush.
I think FF says do it at set times using this or that.
But just washing the roots and soil out for a fresh start is ultimately all flushing is, if that makes sense… just use plain ph water or cal-mag water if you need to get ppm up to hold a stable ph.
Distilled or water with little to no ppm can’t really be ph balanced.
I only flush if i need to, i dont follows a set schedule. I only flush if ppm starts getting high and plant is locked out.
I flush mine by watering till i get a good gallon of runoff (in 5gal pots) then i check that ppm. I pour that water out and pour till another gallon of run off.
Then check ppm of that pour out and do again.
I would do this as many times as it takes to till the runoff ppm is where i wanted it or like below 400pmm.
When it was 400ppm or lower the vary last gallon i gave would be a nutrient feeding of 600-800ppm so she has a nice fresh meal to much on now that her roots are fresh and clean…

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I watered the plant today with Cal-Mag only. The PH 6.5 and the PPM was 860 going in. The run off was 6.4 PH and the PPM was 360.

So I can probably go up in the nutrients right. No need to flush.

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Correct :+1: