420 Magazine Background

Interesting observation

StonerJ

New Member
OK, so I'm new to hydro. I currently have a single large female plant of unknown strain (from the "free" seeds in an order) that is primarily Indica based upon the leaves & bushiness of the plant. I started out in a 5 gal bucket using DWC. Throughout the veg cycle, everything was fine, plant was growing like crazy, no wild swings in pH, always very healthy looking.

Then, when I flipped the lights to 12/12 and added bloom nutes, changed them every week, it seems like the entire "attitude" of the plant (not that they have attitudes mind you) changed. With fresh nutes, the pH would plunge and twice a day I would have to raise it at least a whole point (1.0). Two weeks in, I decided to change to a bigger res so I moved it to 10 gal res and of course, I changed the nutes every week. I also run a 1/10 hp chiller so my res temps are a constant 68 degrees 24/7. Throughout all of this, the plant stayed green & healthy with no real outward showing issues.

So here I am, hitting the 6 weeks flowering mark in 2 days. From the looks of the trichomes, I'll probably start flushing her and getting her ready for harvest by mid next week. My observation is:

Every time I change nutes, I start out at 600ppm or less, pH settles in nicely at 5.8-5.9 when mixing the nutes into 8 gals of RO water. The next 3 days, the pH plunges by at least 1.0 (check and adjust twice a day), the ppm either rises or doesn't budge at all, and the plant continues to grow buds like crazy and put on weight. OK, so she's not really eating, although she continues to drink about 1/2 liter of water a day. Then after 3-4 days, the pH stabilizes, the ppm begins to drop by 30-40 ppm per day, she drinks more (1 liter per day). Each successive day after that, the pH rises slightly (maybe 0.1) and the ppm drops by 30-40 ppm. Seems like she'll just keep doing this as long as i do nothing but top her off with RO water.

Anyway, my observation is that she seems to be so consistent that its predictable.

1. Change nutes, set pH at 5.8-5.9, set ppm at 600 or less

2. Days 1-4 since nute change, pH drops by 1.0 twice a day, small amount of top off needed, ppm stays the same or rises

3. Day 4-?, pH rises by 0.1 per day, nutes drop by 30-40 ppm per day, full liter of top off per day needed.

She's been doing this exact same thing for 4 weeks now and is so predictable that I am using to my advantage. I'm leaving on a 4 day trip early tomorrow morning so she will be unattended for that time period. I changed my nutes Sunday evening (4 days ago), dealt with the daily pH plunge & top off for a few days, she stabilized last evening only dropping from 5.98 to 5.6 and was still 5.6 this morning with a 40 ppm drop in nutes overnight, and I'm leaving tomorrow. I expect (hope?) that she'll be stable now for 4 days until I return. The only thing I have set up is a small battery powered waterer stuck into a gal of RO water that will pump 400 ml into the res twice a day to keep levels fairly constant.

I hope I'm right and she stays on course with minimal pH rise but after 4 weeks of this, I have to say that I'm pretty confident that she won't be any higher 6.1 when I return, nutes will be down by probably 120-150 ppm, and my res level should be within 1/2" of where it should be.

I'm hopin!

:thumb::MoreNutes::thumb::MoreNutes::thumb::MoreNutes:
 

StonerJ

New Member
Came back tonight after 4 days away. Wow, the pH was 5.69/444 ppm. I left 4 days ago and it was 5.6/514 Unbelievable, once she stabilized 3 days after the nute change, she's steady as a rock. Water was down maybe 1 liter (out of 8 gals). That's no hydro maintenance for 4 days. Oh, and noticeable new growth & ripening. I like this a lot.

And so I wonder..... is it just the pH buffering (or lack thereof) that is causing the pH plunges twice daily? If I mix the solution and aerate it for 48-72 hrs ahead of the res change would it eliminate the unstable period for the plant and generate steady, constant growth? Opinions?

:thumb:
 

StonerJ

New Member
Could it be some bacteria or algae that causes this. Are you running organics at all? (Just a guess)

Not organic, using Technaflora BC nutes and I'm bacteria & algae free. If I had algae or bacteria it would never stabilize. I also run a 1/10hp chiller so my solution temp is a constant 68 degrees. After the first 3 days when it stabilizes, it stays steady with no adjustments and nothing but top off water for as long as 8-10 days. I think the pH plunge for the first 3 days after the change is caused by the instability of the solution since I mix the nutes into RO water, stir for a minute or so, then pump the old solution out & the new solution in. My next change in which I'll start the pre-harvest flush I'll add the flushing solution and aerate it with a dual diaphragm pump for a few hours in a separate res before pumping it in so everything should be thoroughly mixed & aerated which will hopefully eliminate the unstable 3 day period right after the change.
 

SpaceGhost

New Member
And so I wonder..... is it just the pH buffering (or lack thereof) that is causing the pH plunges twice daily? If I mix the solution and aerate it for 48-72 hrs ahead of the res change would it eliminate the unstable period for the plant and generate steady, constant growth? Opinions?

:thumb:

Just bubbling the water ahead of time and ph it after 24hrs, until stable. I've found that it takes a couple times then it will lock at what you set it at.
 

StonerJ

New Member
I'll give bubbling it for 24 hrs before adjusting pH a try on my next grow. I'm at the point with my current plant where I'm ready to start the final clear water flush tomorrow for 4-5 days. In the meantime, the res contains just a ripening formula to fatten things up (Cal-Mag & Sulfur) and the plant seems to be liking it. It eats about 20ppm per day and the buds continue to get fatter & swell up.

:thumb:
 
Top Bottom