The pH in soil should be around 6.0 - 6.5. Any higher and your plant will lockout nutrients.
Hopefully this chart will help. The range is different but I water at a 6.0 and the runoff is around 6.5 and I’ve had good results with it.
Actually bud soil should be around 6.3-6.8 but 6.5 being the sweet spot,
@pavala I’m going to go ahead and guess this is a calcium deficiency but its just my guess based off this chart here
Thanks for the replies guys, I will adjust the ph and hope for new growth.
This is the better spot to post this question, and the above advice is good. The pH might be contributing to nutrient deficiency problems. 6.5 is target pH for soil. If it is a soilless media you might need a lower pH. It is likely you need more calcium and phosphorus anyway, you will need more phosphorus and potassium in general during flower anyways. A flush before the transition to flower is not necessarily needed, unless you have a nutrient salt toxicity that has built up in your soil, but I doubt that was a problem here.
You need to fill out a support ticket. This way we could give you an informed answer instead of guessing.
Reason we need support ticket:
You did not mention method of growing: Soil, soil less, hydro???
PH 7.0 is neutral but on the high side for most optimum growing.
As mention 6.5 for soil is the tarhet
5.8 for hydro, and soil less mediums have to be experimented with in order to find the correct PH for Cannabis. After years of using ProMix BX I have concluded that PH should be 6.1-6.5 despite the website suggesting a PH of 5.5-5.8 This acidic of a solution does not work as well for Cannabis as does the higher almost soil target PH.
Hope this helps clarify why we need more information. If you are at 7.0 in hydro; That is the total issue, causing nutrient lockout.
Actually ProMix doesn’t recommend a pH of 5.5-5.8, they recommend a pH of of 5.8 to 6.2 for most plants, “General Plant Group”.
And they recommend a pH of 6.0 to 6.6 for the “Geranium Plant Group”. Or plants that are sensitive to Iron and Manganese toxicity if the pH goes down below its optimum level. And some plant species in this group also acidify the growing medium because the plants release acidifying ions, which cannabis does do, especially during flower.
These were planted in foxfarm ocean forest. And yea I did notice the runoff to be a little too low around 5.5
Thanks MacG. I thought you guys posted the pH lower. My mistake. So my experimenting came up with basically the same PH as the company, after all. Cool
So; Now I am confused. This is what you called me on in the Labs. I posted to use 6.3-6.7 and you contradicted me. No argument here. Just find this curious. This is what I have been teaching all along.
Nope, I was commenting on a post where you said 6.8 was ideal in ProMix, but maybe it was a mistype, or other misunderstanding.
I’m glad we are on the same page and in agreement now.
Have you used nutrients from thew start? If you did you most likely made the soil toxic by adding too much nitrogen, etc…
What exactly are you using from Foxfarm? You mentioned no Calcium in Foxfarm and that is not true. Grow Big has Calcium in it. 2.0% to be exact
Let us know.
I had an autoflower do this and the other photo plants were fine
The conditions in each plant’s container can actually end up with different pH, even if you feel you are giving them all the same treatment.
Also, different strains, even among regular photo strains, maybe more so with auto strains, will be more or less sensitive to things like nutrient deficiencies, toxicities, or pH fluctuations.
So the fact that your auto was the only one that showed problems makes sense.
Are they getting fresh air? It looks like slight nutrient burn, how often are you fertilizing? Organic or not organic? have you added any earthworm castings?
big bloom/tiger bloom, I used grow big for veg. I just measured my ph, it was at 4.5 so i think this is a lock up, am I wrong?