Yellow tops, week 2, seedlings

The tops of my seedlings are a bright yellow. I’m using high-quality soil and since I’m only in my 2nd week I’m surprised this could be soil related.

I amended the soil with Down to Earth Starter Mix 3-3-3. I’ve fertilized once at half strength with Fox Farms Boomerang and Big Bloom as per the FF feeding schedule. I’ve also added a tiny amount of Rapid Start and SuperThrive in that feeding.IMG_20190115_170203791|666x500

  • 100% Indica “Afghan 1” bought at local dispensary
  • Fox Farms CocoLoco
  • Pint plastic
  • pH Not tested
  • Indoor
  • 200 metal halide
  • 70-80°F
  • ~30% RH
  • Ventilation is just air circulation
  • No AC, Humidifier, De-humidifier,
  • Co2; No

Any ideas? Thanks!

That soil has enough nutrients in it to get the plant established. Without a picture I’m leaning towards nutrient burn. Could you post a pic?

1 Like

Here you go! Thanks for looking.


Not testing your ph is the problem. You really need a way to measure what your giving your plants. If not, they won’t be able to uptake any of what you’re giving them. Ph of coco is 5.5-6.2 with 5.8 being the sweet spot, but you added other mixtures to your medium as well. That will change the ph too. I’d look into getting a ph meter at the very least and would also recommend a ppm/ec meter and ph up/down solution. :v::bear:


I guess I didn’t think it would be necessary so early. I have one of those dual-pronged probes as well as test strips. I’ll give it a look. I’ll report back. Thanks a bunch, MattyBear.


@Digibeast @MattyBear is a great grower and great mentor this guy can help with the best of them he has you covered :wink::pig:


The 2-pronged tester shows a pH of about 7.2. I can’t imagine how this happened. I’m going to use vinegar to lower the pH. Thanks again, MB.

It sure looks like it, Hogmaster. pH was the last thing I would have thought about since everything was off-the-shelf.

Get a good PH pen mate, more accurate than the 2 pronged tester @MattyBear will see you right :+1:


I agree those prong ones are good if you want to check moisture or light. But the ph was off over 2 whole points. It was showing 8.0 while the digital ph meter showed 6.0. So I don’t trust them when it comes to ph. Sure way to kill a plant thinking ph is extremely high when in fact it’s the opposite. And you’ll spend lots of time trying to get it right and you just end up chasing your tail. A good light a good ph
meter are top on my list of necessities.:blush:


It looks like pH was the culprit. I’m not sure if the plants will recover, but that’s a bunch for the help!

1 Like

I am having trouble with yellow seedlings too .

Any suggestions on what’s going on ?