What might cause ppm to rise and pH to drop?

[Green Thumb MN]

Three plants in my 2x4 tent. DWC 5 gal buckets. Day 42 of flower. Day 55 of 12/12. Day 101 from seed.

The AK47 is the only one with this issue.

I am using GH Flora nutes, ppm at res change was 600-650. pH was 5.8. I am using r/o water and adding back cal/mag.

Today, 7 days later, ppm 1000, ph 5.2

Temps are: 70-75 top of plants, 66-70 bottom of tent. Res is usually about 68 degrees, 71 tops.

AK47


Northern Lights


White Russian

 

[superstoner1]

Think about it. When you add nutes does the pH rise or lower? It lowers. So when the plant drinks more water than nutes the ppm will go up, meaning more nutes in less water, and the pH will lower because more nutes in less water.
As for the days, almost all breeders start flowering times at the start of 12/12, not when pistils come in. The chemical change starts almost immediately but it takes a while to physically show but its still flowering time. If I went by that I would have some strains that finish in 39-42 days not the 52-55 they do take and what they were claimed to take by the breeder.

 

[1itsme]

the ppms are rising bc the plants are taking more water than nutes. ph dropping is bc the plant is taking more of an alkaline nute than an acid one ( k,c...). Unless your roots are brown, in which case it's rr eating the root's. hth

 

[Green Thumb MN]

Think about it. When you add nutes does the pH rise or lower? It lowers. So when the plant drinks more water than nutes the ppm will go up, meaning more nutes in less water, and the pH will lower because more nutes in less water.
As for the days, almost all breeders start flowering times at the start of 12/12, not when pistils come in. The chemical change starts almost immediately but it takes a while to physically show but its still flowering time. If I went by that I would have some strains that finish in 39-42 days not the 52-55 they do take and what they were claimed to take by the breeder.

Makes sense! I guess I am closer to harvest than I thought. The AK47 looks closest to my first-timer eyes. I will get some better trichome pics when light comes back on.

Thanks SS

 

[Green Thumb MN]

the ppms are rising bc the plants are taking more water than nutes. ph dropping is bc the plant is taking more of an alkaline nute than an acid one ( k,c...). Unless your roots are brown, in which case it's rr eating the root's. hth

The roots are very dark, but not slimy, smelly or soft. I have been using a powder mycorrhizae & bacteria additive that turned them almost black.

Probably just keep watching, may be nearly ready for harvest.

Thanks itsme!

 

[1itsme]

If your doing the bennie thing in dwc you should check out heisenburg's tea thread. I used it to cure root rot 1 time, it's good stuff.
https://www.rollitup.org/dwc-bubbleponics/361430-dwc-root-slime-cure-aka.html

 

[BigLittlejohn]

I would suggest that ideally, you want the plant to take in relative equal levels of nutes and water, leaving the ph and ppm of the water relatively stable. I would further suggest that if you are near the end, the plant is not necessarily wanting to be fed at that level and is therefore taking in more water. Do you top off your buckets? If so, I would top off with just RO water and drop your ppm from 650 to around 550 and see how the plant reacts.

One thing that tells me I am doing something right is when I check my bucket and the water level has decreased 50% or more but the PPM and PH are about where they were when I last checked.

Those are my non-expert thoughts.

 

[mrstyleZ]

the ppms are rising bc the plants are taking more water than nutes. ph dropping is bc the plant is taking more of an alkaline nute than an acid one ( k,c...). Unless your roots are brown, in which case it's rr eating the root's. hth

I'm having this issue right now. my roots are somewhat brown but I thought this was from the dark additives. Can you explain what rr is please.

 

[hellmutt bones]

There a point when your plant will not take in the same amount of nutes because its close to harvest the plant is filtering out the water and nutes therefore its rejecting nutes. So yes your ppm and ph will be altered all you can do is add water to dilute as much nutrients as you can and watch ph as much as possible.

 

[c3_Genetics]

There a point when your plant will not take in the same amount of nutes because its close to harvest the plant is filtering out the water and nutes therefore its rejecting nutes. So yes your ppm and ph will be altered all you can do is add water to dilute as much nutrients as you can and watch ph as much as possible.

I know this is a really old post, but i can confirm this is true, atleast sometimes. This is exactly whats happening with my two girls right now about a week maybe 2 from harvest and they are some of the thickest nicest looking buds ive ever grown! Gave them the lowest dose of their last nutes and my ppms are literally doubling but the water level is going down like normal. Just been topping off everyday with a gal of r.o water to dilute and basically "flush" them for their last few days.