Leaves browning ..please help

I'll give as much info up front as I can.

White Rhino 42 days into flowering for the big girl, 3 lil girls are 3.5 weeks into flowering.
400w HPS, exhaust through a carbon filter, smaller fan is on air intake line
Dehumidifer is inside tent and sent to keep humidity at 40%
My temp never gets above 85...at night it can get down to 70.
Soil grow in a 4x4x6 grow tent
Soil PH is 7 it's just miracle grow I think.
I water every 3-4 days as the plant shows it needs it ( I do not know water PH but I am going to find it out later today)
Nutes: I use a couple of drops of superthrive, though I might have been overzealous in the beginning. 1 table spoon of blackstrap mollases every other time once the plant has been flowering for 4-5 weeks.
a sprinkling of bat guano every other watering.

I'm going to post some pics right now, but I will have much better pictures later today about 6PM eastern time.

So this is my 4th time through with this strain, I am pretty familar with it now. I have always had yellowing fan leaves. I believe I had a small mite infestation a few months back that I think I have knocked back through a very aggressive counter-attack. I am seeing odd damage/rotting to my bottom leaves and vegetation. It may be further proof of mites but it isn't really consistent with pictures I have seen online. Many leaves are browning and almost look like they are rotting. Here are some pictures, any help much appreciated. Better pictures coming. The big leave in picture three was actually from the top end of the plant, but most leaves at the top are green and healthy at this point.

Pic 1 is the big picture of the whole garden. Currently the big plant is showing the bad symptoms. There are 3 smaller plants about 3-4 weeks in into flowering. The gross looking leaves are from the big plant.

The final leave that is yellowing just the the tips was taken from one of the smaller plants, is that nute burn?

My guess is either my PH in my water is messed up. I know for a fact I have hard water, not sure how that might effect things. Please help, I know this has to be effecting yields


Thanks for any help...glad to start sharing some info.

Thoughts anyone?

looks just like a magnesium deficiency. just had this same problem. get some cal-mag+ for bonticare of any magnesium supplement and it will start to work right away... really helped all my plants

c5rftw said:

looks just like a magnesium deficiency. just had this same problem. get some cal-mag+ for bonticare of any magnesium supplement and it will start to work right away... really helped all my plants

Click to expand...

thanks for the reply...I'll look into treating this.

If your water is hard, there should be plenty of minerals in there so you shouldn't be experiencing a Mg deficiency (which is what your plants look like) unless your pH is really out of whack and locking out Ca and Mg.
Hard water often has a high pH and the minerals in it buffer it against changes so it's hard to knock it down and keep it down. Buying RO water is a reasonable alternative with fewer problems. Less than 50 cents a gallon near me.
But then you WILL need a cal-mag supplement, because the water contains none. Well, actually the store bought water is 40-50 ppm while home-made RO water is more like 5-10 ppm. I think they add some minerals back to improve the taste.

You can quickly treat the problem by spraying with 1/2 tsp epsom salts dissolved in 32 oz water plus a couple of drops of liquid soap. drench all the foliage with that. That should stop the progress of leaf loss within days. Resolve your pH problem for a longer term solution.

shnkrmn said:

If your water is hard, there should be plenty of minerals in there so you shouldn't be experiencing a Mg deficiency (which is what your plants look like) unless your pH is really out of whack and locking out Ca and Mg.
Hard water often has a high pH and the minerals in it buffer it against changes so it's hard to knock it down and keep it down. Buying RO water is a reasonable alternative with fewer problems. Less than 50 cents a gallon near me.
But then you WILL need a cal-mag supplement, because the water contains none. Well, actually the store bought water is 40-50 ppm while home-made RO water is more like 5-10 ppm. I think they add some minerals back to improve the taste.

You can quickly treat the problem by spraying with 1/2 tsp epsom salts dissolved in 32 oz water plus a couple of drops of liquid soap. drench all the foliage with that. That should stop the progress of leaf loss within days. Resolve your pH problem for a longer term solution.

Click to expand...

Thanks for the info. I believe water is hard yes, I have never had it tested before to find out how hard it is. It's safe to spray this mixture even on buds?

What is my ideal PH for the soil and for my water? I'm a complete newb...so what is RO water? Reverse osmosis? Maybe I should just start buying it by the gallon from the store? I believe my water has been causing me issues all along...they are just really amplified now for some reason.

Magnesium deficiency will exhibit a yellowing (which may turn brown) and interveinal chlorosis beginning in the older leaves. The older leaves will be the first to develop interveinal chlorosis. Starting at leaf margin or tip and progressing inward between the veins.

Trust me man.. order or go buy some if you think its bad(spread throughout). It doesn't look that bad

I don't think it's all that bad, and I will go buy some today.

I just see some pictures where everyone leaves look so nice, plush and green. This white rhino has never looked like that for me but I can't help but think I am missing something and it cold be effecting yeild.

I've got about 5 weeks left for this plant and then I am really going to tighten up my feeding regimen for this next go around, I have been quite lazy with my measuring and I know that doesn't help.

yeah so the PH of my tap water is high...like at least 9.0....it really was off the chart....really blue in color while the chart stopped at greenish blue. Pretty sure my water sucks


I picked up a bunch of RO water from the store and a quart of cal-mag supplement for the water.

What does watering with water with a PH that high do to a plant? What else do i now need to look to counterbalance due to this high ph that i have been using?