Phosphorous Deficiency?? Something else?

[HIonCANNABI420]

Hey all, so I have this plant that has received a full nutrient feed (Botanicare, Pure), plus Mammoth P. I have been feeding weekly with this formula. 3 weeks ago I noticed what appeared to be nutrient burn. So the following 2 weeks I fed with just pH’d water along with Mammoth P, the plant seemed happy and the issue seemed to plateau. Last week I decided to keep feeding the pH’d water with Mammoth P, I’m about a week or two from harvest. This past feeding I noticed worsening symptoms. This has lead me to the belief that this may be a Phosporous deficiency because of the blotched spots on the leaves, this could also signify other deficiencies but my thought process is this: Mammoth P helps aid in the uptake of Phosporous... is it possible that the plant is actually looking for more Phosporous?? But with harvest looming, should I stop all nutrient and Mammoth P?? Just monitor the plant closely and harvest should I see anything that warrants the axe?

[Toker1]

Soil or hydro? Could be a P deficiency. You might be experiencing lock out. What is the PH of the medium or runoff?

[D.A.A.S.69]

Yep, need more information,

[Canuck147]

Forget the nutrients and just water - with or without tea or molasses or just water.

[HIonCANNABI420]

Soil. Water going in is between 6.1-6.5, runoff has been around 6.2

[Toker1]

I think 6.2 is low for P in soil. This chart (attached in next post) recommends 6.5 - 7.0.
Seems like your PH is incorrect for this particular element.

[Toker1]

Try to stick in this range. 6.3-6.8 for soil

[HIonCANNABI420]

I’d tend to agree except by Botanicare’s instructions, they recommend using a pH between 5.5-6.5

[Toker1]

That’s for hydro my man. Soil is different.

[HIonCANNABI420]

Toker1 I stand corrected. Def looks like soil should be more between 6.0-6.8, per some additional research. Thank you for pointing that out!! It’s kind of silly that Botanicare doesn’t suggest that on their SOIL line of nutrients haha.

Being so close to harvest, I’ll more than likely just stick to pH’d water but probably in the range of 6.5-6.8 to help adjust the soil pH through the flush. Thank you again!

[Toker1]

No prob!
Yeah these nutrient lines also give general info that might be true for most plants grown as a general thing. You want to be looking for information specific to the MJ plant.