Hi all. I understand that RO water has nothing in it to buffer ph, which is why ph pens can't really determine ph, or the readings swing wildly. In a soil grow, does this matter? I'm trying to determine if I need to do anything to the RO water for final flush of a soil grow.
check the run off Dude...it will tell you what the root zone ph is or hopefully close to it...being that your in soil the run off should be between 6.5 and 7.2. ..as far as the water your using, after establishing what the run off ph is, that number should give you the info you need to adjust the water before you pour it so that the run off is correct...whatever it needs to be in order to get the run off pH correct and stable is the only way to go good luck and happy grows Sent from my SM-G600FY using Tapatalk
Runoff is usually around 6.5, sometimes a tad lower. That's not really the question though: Assuming soil ph is ideal, does plain RO water needed to be adjusted (for a flush), or does it not matter since it is inert? Sent from my HTC One M9 using Tapatalk
flushing with straight ro water is OK...as it has nothing in it....experienced growers flush with 1/4 strength nutrient solution for about a week then the last week or so straight clean ph adjusted water...in your case ro water..which is actually better than tap for flushing.. good luck and good grows Sent from my SM-G600FY using Tapatalk
Thanks. Gonna go with a longer flush (2.5 weeks) because there is so much phosphorus in the soil as it is, based on a soil test. So much so that it caused mag and calcium issues during flower, which totally sucks, but flowers still look good. Leaves on one are embarrassingly chlorosis-plagued. Gonna let it push through with the flush and see how it goes. Peace. Sent from my HTC One M9 using Tapatalk
If you're flushing right before harvesting, no reason to pH water. You keep pH levels in range to help the plant's roots take up nutrients more easily and if your plant is mature and ready to pull, it's finished working. You're attempting to pull out nutrients or chemicals from the plant with the flush, so no big deal. If you flush for some reason during the cycle of the plant and it has more time to go to mature, I would pH the water then. But I don't flush. I did it a few times and decided that it was much too much work to do to not see any difference in the taste of the plant. I think whether you flush your plant or not depends a lot on how heavily you fertilized your plant during it's life. We don't use much above what comes in the soil. Nutes are just plant food and though important to the growth and health of the plant, are not nearly as important in the growth of the plant as lighting is. You have to have strong enough wattage and good enough quality of light (proper spectrum for particular cycle) to force these plants to grow in the indoor grow situation. Nutes do not determine the rate of growth or the size of the plant. Light does that. If you didn't use a lot of extra nutes on your plants, then I wouldn't go to all the trouble. If you gave nutes constantly throughout the grow, then you maybe should give them a flush. TWW
You're first sentence contradicts its self. Yes always ph your water. Sent from my iPhone using Grasscity Forum
I've decided not to ph. I did an experiment where I added one drop of ph Up to the RO water, and as I expected the ph shot up a crazy amount. It went from 6.2 to 8.0. My conclusion is that the RO water will take on the ph of whatever it comes into contact with very quickly. So, if the soil ph is good, which it is, I don't see a need to adjust ph of the RO water. Sent from my HTC One M9 using Tapatalk
well let's put it liken this....NOT ph'ing the water..to flush (and listening to someone who doesnt flush and says because its too much work) could possibly do something you don't want...and would be considered an experiment..OK...so ..ph'ing the water at the end is by the book, normal and goes along with all you've been doing ...HMMM tough choice huh? (really?) why experiment with the last phase and arguably the most important phase of the plant..as flushing is needed for a number of things to happen and other things to occur...and get better (burn ability) flavor etc. tip of the day...DON'T listen to someone who has decided it's too much work to flush and says fuck it I'm flushing this bitch in the shower with me everyday before I go to work..LOL or however Dude goes about it...it's funny he has advice on not ph'ing the water but then says he doesn't flush anyway... Other growers should weigh in on this one good luck and good grows Sent from my SM-G600FY using Tapatalk
Thanks for all the info and opinions. Like I said, the ph of the RO swings wildly based on what the water comes into contact with since it has nothing in it. Hence why one drop of phUp had such a dramatic effect in my test. I don't think adding Up/Down to get a dialed-in ph will add any value. In fact, it might be too hard to do, given the sensitivity. One drop could affect things too drastically to the point that trying to adjust in small increments becomes virtually impossible. My soil has a good ph. I'll ph the runoff and let you know. Thanks again. Peace. Oh, and remember, this is not about ph'ing for flush, it is specific to ph'ing RO water (during flush). Glad there is a good community here. Sent from my HTC One M9 using Tapatalk
exactly the run off is what's important ..IF it's in the correct range a tv the run off...and you didn't adjust it before....then your situation tells you, you won't need to adjust....it's all about the run off...but if the runoff is out of range...then yes ...do adjust before you pour!!.whatever you have to do to get the runoff in the range!! good luck and keep us posted Sent from my SM-G600FY using Tapatalk
Yep, I will. Today is watering day. Stay tuned. Thanks. Peace. Sent from my HTC One M9 using Tapatalk
If your ph is within range for soil 6.0-7.0 your fine. If not adjust your ph appropriately Sent from my iPhone using Grasscity Forum
PH for soil STARTS AT 6.5 NOT 6.0...6.0 is good hydro ph (I use 5.8) if you lock in soil plants at 6.0 it will still grow but slower and sluggish and not as green ...lime green if you will....you can search all day on Google and you won't find one place that says a good ph for soil is 6.0...it's Not .....now with coco coir...it is...but that's because coco coir doesn't have soil...so it's considered hydro and should be treated as such... good luck good grows and keep us posted Sent from my SM-G600FY using Tapatalk
One update: As a sanity test before watering later, I did another experiment. I took about 8 oz of RO water. Ph was about 6.1. I added 1 drop of phUp which immediately took it to about 9.8. I added a second drop, which took it to about 10.5. (notice the diminishing effect). Then, I mixed a small amount of soil, which has a ph of approximately 6.5, with the solution, about 3 tablespoons. I mixed throughly and strained the solution. I recorded the water ph, and it immediately dropped all the way down to 6.8. My Conclusion: RO water will almost immediately take on the ph of the substrate, regardless of the initial ph of the RO. Perhaps the only reason the solution didn't come all the way to 6.5 (soil ph) is because different tools were used to measure the ph of the soil vs. water, or because the RO had a slight amount of buffer after adding phUp, or a little bit of both. Therefore, I don't feel the need to adjust ph of pure RO water prior to watering for the flush. I hope this little experiment helps others. I'll still keep you posted on ph runoff after watering. Peace. Sent from my HTC One M9 using Tapatalk
Did the same with ph down. 2 drops to the RO took it to 3.6. Mixed in 3 tablespoons of soil, and ph bounces almost immediately up to 5.9. Here there was a larger delta between the ph of the solution and the ph of the soil, but it's still within 0.6 units. The ph of the RO water jumped 2.2 units with a small amount of soil added. I did this with no phUp/Down also, and the solution came right out to a perfect 6.5, exactly matching that of the soil. Sent from my HTC One M9 using Tapatalk
good shit that's where you want it. at run off however you get there! good luck and post pics Sent from my SM-G600FY using Tapatalk
Add a very slight amount of cal/mag or another nutrient in it before measuring. Molasses is also great for aiding in flush. The sugar in the water helps dissolve nutrient salts. It may read and stablilize better with just a little molasses dissolved in the water. It's also a little known fact that some nutrients dissolve better when there's a lite amount already in the solution you're flushing with. Flushing with a super light nutrient solution is more effective then just water. It's almost like some nutrients dissolve themselves. I guess if you only feed water it's hard but typically if you bottle feed you ph after you mix your solution. It will read after that. I use rainwater that is 0ppm and won't register out of the tap also but I always check it after adding everything. It will read then.
Very true experienced growers flush with 1/4 strength nutes..about a week then the rest just water...it forces the plant to use the little bit that in Thier until there is no more...that's when the real taste comes out!! good luck and good grows Sent from my SM-G600FY using Tapatalk