Pics inside! Cal/mag def in flower stage??

Here we are, 3.5 weeks into flowering and I am getting the issue of yellowing upper leaves accompanied by brown spotting within those leaves. Some leaves are green w the spots so I'm assuming the yellowing ones are the more infected.

Some background:
Strain: nirvana northern light autoflower
Lights: 250w HPS. 2 65w CFLs
Soil: ffof
Nutes: fox far trio, supplemented dolomite lime for cal mag boost
Light schedule: 18/6
Temps: 70-81 F
Humidity: 35-42%
Ph of soil: using the drop method with runoff I get a solid 6.0 reading

I always test my water ph to around 6-6.5.

This is my first grow n I believe I'm halfway into my flowering stage. So not sure if I should just ride the next 3.5 weeks out or find a solution.


Look at the lower left leaf for spotting/yellowing


spotting/yellowing in newer growth


Top of plant has twisty new growth(only 1 of 3 to have twisty growth like this)

It's hard to say because the photos are small and lighting is unbalanced. It doesn't look like ca or mg def to me. I see purplish blotching like p def. Yellowing like n def (but can't tell because of the color of the lighting). Maybe another def with yellow veins.

When I see multiple defs, I'm thinking salt build up, acidic soil, nute lockout. I would flush and feed light nutes. Maybe foliar feed to get nutes to the plant if there is soil lockout. (But, must be weighed against risk of bud rot.).

Have you been monitoring your runoff ph and ppm? Runoff ph isn't accurate as a single reading, but the trend over time (along with ppm trend) would have warned you of salt buildup, acidification.

I have been monitoring run off ph at a stable 6.0 6.1

As for PPM, I have no clue. Not sure how to even find that out

Thanks for replying!


edit: just last night I flushed the plant with ph'd water and dolomite lime. A few days ago it was not this intense. Just a few specs on the leaves which I thought was a cal-mag def.
It soon then turned into this, more noticeable, more spottings, and the leaves beginning to straight up die. Before I do anything should I wait until my soil dries up?

I don't see ca or mg def. The brown spots look more blotchy like P def, maybe purple'ish like that too. Yellow looks like K def, maybe N. Are you letting them dry adequately between waterings? Soil ph rises as it dries. If you don't let it dry enough you reduce the nutrient availability at higher ph range.

How much do you feed, how often?

I appreciate the insight dude. Right now I feed on a situational basis. I lift the pot to tell for the most part. I do check the soil w my finger n I do typically let them dry out a bit.

I don't feed much to be honest. I hear the FFOF gives plenty. WHen I do feed it is prob 25% of the dose

I gave dolomite lime to them about 3 days ago. Nothing since.

edit: I believed it was a P def as well. Should I wait to feed w nutes? How long?
Also, should I trim those dirty ugly leaves? Or keep them on. Some are real close to bud sights

did you change to flower nutrients when you switched to 12/12?

novapants said:

I gave dolomite lime to them about 3 days ago. Nothing since.

edit: I believed it was a P def as well. Should I wait to feed w nutes? How long?
Also, should I trim those dirty ugly leaves? Or keep them on. Some are real close to bud sights

Click to expand...

I don't have experience with that soil and nutrient. You'd need someone who uses it to answer if you're feeding enough. It the soil isn't acidic from salt build up, and you're letting them dry adequately, then it seems the only alternative is underfeeding. That's hard to believe just because people tend to overfeed and/or overwater, not underfeed.

Regarding dolomite, that should have been amended into the soil before planting. Watering it in takes 10-14 days to affect anything. But, you don't seem to have a ca or mg def, and your runoff doesn't indicate acidic soil. So, I don't think dolomite is the answer.

novapants said:

I appreciate the insight dude. Right now I feed on a situational basis. I lift the pot to tell for the most part. I do check the soil w my finger n I do typically let them dry out a bit.

I don't feed much to be honest. I hear the FFOF gives plenty. WHen I do feed it is prob 25% of the dose

I gave dolomite lime to them about 3 days ago. Nothing since.

edit: I believed it was a P def as well. Should I wait to feed w nutes? How long?
Also, should I trim those dirty ugly leaves? Or keep them on. Some are real close to bud sights

Click to expand...

I would be feeding her full strength foxfarms if I were u bro!
do it now and leave those leafs on at least until you fix the problem

How much do I feed 2 gallon pots of nutes? I understand my doses per gallon but how many gallons should I run thru the pot while feeding?

if you aim for 10% run off of feed jug, youll be ok, but if your soils very dry or you have big root mass make sure you water slowly bit by bit so it doesent just pour through the pot,

novapants said:

How much do I feed 2 gallon pots of nutes? I understand my doses per gallon but how many gallons should I run thru the pot while feeding?

Click to expand...

With any nutrient, I would water until 20% runoff. That helps reduce salt build up. It doesn't sound like you have build up. When I have my strength dialed in, I might only get 5% runoff and not worry about it because I know I'm feeding enough.

Just water until you get runoff. Don't water until the soil is dry. The best way to know when it's dry is to wait until the leaves droop, lift the container to assess its weight. When you learn how light that feels, you can know what "too dry" feels like. It doesn't hurt the plant to let it dry until the leaves droop. They'll bounce back in 20-30 minutes. But, it is a stress. You don't want to do it all the time. You're trading off a one-time stress to reduce the possibility of ongoing stress by watering too soon.

novapants said:

I appreciate the insight dude. Right now I feed on a situational basis. I lift the pot to tell for the most part. I do check the soil w my finger n I do typically let them dry out a bit.

I don't feed much to be honest. I hear the FFOF gives plenty. WHen I do feed it is prob 25% of the dose

I gave dolomite lime to them about 3 days ago. Nothing since.

edit: I believed it was a P def as well. Should I wait to feed w nutes? How long?
Also, should I trim those dirty ugly leaves? Or keep them on. Some are real close to bud sights

Click to expand...

You really need to feed at full strength by week 4 of flowering. The foxfarm soil is 100% depleted by now if you were vegging in that soil.

Im a FF user, soil and nutes. You are locking out some nutes with that ph. Needs to be around 6.5-7.0. Big plants, small soil= hungry gals. Feed them. Water half gallon at a time. Dont sweat the runoff. Add half teaspoon of epsom with the watering, make sure they get some N with that also. When N is lacking you will have a domino effect of lockouts