Here’s a couple plants with yellow leaves. Last grow, my plants were nice and green. Nothing changed, although these are different seeds than last time. But why are these leaves this color? Light is correct, ph is correct (I think), water is fine (again, last grow everything was green).
Also these plants are small compared to last grow. I assume that’s because of the different genetics of the seeds. But could it be correlated with the yellow leaves problem?
It’s not just the plants. I turned a little yellow looking at them pictures too. 
under fed or overwatered is my guess…
what are you giving nutrient wise?
The more info we have the better we can diagnose. That first picture I would say is just hungry. The second is locked up in the root zone. Either pH or over watered given the little info provided.
What is you pH an EC going in and runoff? What is your water source pH and EC? What is the medium? Temp/humidity? How often do you water?
No nutrients to speak of at this point. I did give them some water with a fraction of a dose of Miracle Grow to see what would happen. No change, not even sure if there was enough to register either way.
Watering, just getting them good and wet and leaving them until they dry out and the whole thing is light. This was similar to how I watered last grow, which worked pretty well.
I have been using a cheap pH monitor, which says pH is fine. But I’m going to get some test strips for a second opinion. No nutrients to speak of other than a tiny Miracle Grow experiment. Need to get an EC monitor too. Using Nature’s Care Miracle Grow organic potting soil. . . . I’ll do some tests and report what I find out. Thanks–
well we have effectively found your issue.
your plants are hungry and want food… there is not enough for it in the soil so it’s eating itself… are you using recycled soil from your last grow to plant these?
Underfed and overwatered
I’ll have to say it’s a ph issue
I’ll check. Cheap meter says it’s ok, but I’ll use some ph strips to confirm
Gonna try watering less. Also, what should I feed them?
No it’s “brand new” potting soil. What should I feed them?
There are lots of choices for food, but Miracle Grow is way down on the list 
Im sure you will get several different recommendations, but my current favorite is Mega Crop.
You can get a 1kg bag for $15 plus shipping. That should make around 200 gallons of nute mix.
Check out this thread.
They have been getting (mostly) rave reviews.
Ive used it in a soil grow and two hydro grows so far, and it works great, is easy to work with. You may need to add some additional CalMag depending on your soil and how strong you mix it. Other than that, its a one stop deal.
You’re in soil, seriously doubt it is a ph issue. Soil is a buffer. I use megacrop also, keeps it simple. At least an organic fish fertilizer w/kelp or something. Try 1/2 strength to start
I have 2 probes on my desk here. 
They suck. Even the more expensive one. They are handy for seeing/confirming if it’s WAY out of wack but not for fine tuning, imo. I’ve done the runoff test a couple of times but from what I’ve read it’s tricky to do “properly” (i.e. distilled water twice, ignore first runoff, capture first drops of second runoff).
While I support your science-oriented approach my low-buck experience & Yoda 
say get some kelp meal & make a liquid feed and or worm-castings. Be careful not to over-do it like I’m probably inclined. hehe
properly healthy soil or outdoor soil will act as a ph buffer but don’t believe for a second that soil growers can’t get locked out nutes based on ph… it happens… more frequently than soil growers care to admit and is usually looked upon as underfeeding or overwatering so it gets handled as such while never actually addressing the problem…
I’ve had catastrophic failures in soil, runoff 1000 PPM and a very low pH. In my case it was over use of a garlic ferment that literally killed all my microbes. Its these microbes that help control pH in the rhizosphere.
You keep saying your meter says the pH is “ok” does it not give you a number? Or is it one of those soil probes from the hardware store.
Agreed @toastyjakes and @ReikoX but they should try the obvious first, like nutrients. They haven’t fed them at all yet and the age of that plant seems about when the nutes already in the soil get used up. More than likely a heavy feeding strain wouldn’t you think?
It’s one of those ph / moisture / light meters with the two long, different metal probes, about ten dollars. It says the pH is about 7.5. After reading a little I’m finding out that is too high. Can I use vinegar to bring it down? What should I use to get the pH right? --I’ll read the websites a little deeper. The vinegar thing was the first pH balance method that came up.
7.5 is a bit high for cannabis. I wouldn’t suggest vinigar personally, though some have used it successfully. If you are stuck with miracle grow, use about half of what they suggest for container gardening. This should lower the pH and feed the hungry girls. Win, win.
