Help! Ppm's dropping a lot between res change

[jackson1988]

2 five gallon buckets with 2 monstrous ladies
1 five gallon bucket is res that is cooled by sitting inside a refrigerator and working very well.
My issue if it is one, is that in my 5th week of flower I have 1200ppm starting at res change which I do every 9 to 10 days. By mid res schedule my ppms are dropping to around 800. I add about 2 gallons per day of RO that is ph'd to 5.6 to 5.9.
Question is am I losing out on growth by not adding nutes between res changes? Ph rises slightly to 6.2 by end of res schedule. I have always just added non nute RO previously but have never had girls drinking so much and draining nutes so quickly. This strain is probably going 10 full weeks maybe more because she is definitely 80% or more sativa

Thanks

 

[Scientific]

Monstrous ladies that are drinking and eating heavily--nice problem to have!

> am I losing out on growth by not adding nutes between res changes?

800 PPM is still a lot of nutes in the res, so my guess would be that if you're losing out on growth, you're not losing a lot.

That said, it seems to me that you have two options to further optimize:

• One would be to just keep doing what you're doing but switch to weekly reservoir changes. That's a lot more work and it sounds like your girls are fine with your current interval, so it's probably not the best choice, but it would result in slightly higher overall nute concentration over time.
• The second option would be to start adding nutes on an ongoing basis, trying to maintain a certain nutrient level. That's more work, too, but a lot easier than a full res change. That's what I did after reading another guy's grow log in which he did the same thing, and we both got great results (though again, it's hard to say that maintaining a constant 1200 PPM, for example, versus letting it drop to 800 would actually give better results without doing an A/B experiment).

My one other thought would be that if you do decide to dose nutes more frequently, be sure of course to watch closely for signs of nutrient excess.

In any case, it sounds like your grow is going great and that we're just talking about a little fine-tuning that may or may not make a difference! (Me, I'd go for it! ) Good luck and have fun!

 

[jackson1988]

Thanks Scientific! I'm going to take your advice and do 7 day res changes and add nutes between trying to keep numbers up. Going to run flora kleen before res change for a few hours to get rid of excessive salts also

 

[Scientific]

Thanks Scientific! I'm going to take your advice and do 7 day res changes and add nutes between trying to keep numbers up. Going to run flora kleen before res change for a few hours to get rid of excessive salts also

Great! I think you can probably skip the FloraKleen, though.

 

[TorturedSoul]

800 PPM is still a lot of nutes in the res

Yes... Five-gallon buckets seem kind of small for "monstrous ladies" - I used to use 23-gallon plastic totes. Although, towards the end of flowering, the free liquid capacity was closer to five than 23 gallons (IIRC, around seven gal.). How much space is left in your five-gallon buckets at this point, after deducting for the root mass? IOW, if you poured the solution out, how much would you be able to pour back in?

Your PPMs are dropping AND your pH is falling gradually - that seems like normal feeding to me. You can observe that your EC/PPM of TDS is falling, but you cannot directly observe what has been consumed. Do you use a multi-part nutrient? If so, try adding a wee bit of the "bloom" component... This should drop your pH while raising your EC/PPM.

Instead of adjusting the water's pH and then adding it to your reservoir, you might add the water, wait an hour or so for the reservoir to stabilize, then check and adjust the pH of the reservoir (again, a little of the bloom component will probably drop it sufficiently - while adding back nutrients.

Gradual drop in pH is normal and denotes feeding. It's when you check it and see that it tanked overnight that you have issues, lol.

Look on a chart of the availability of nutrients vs. pH and you will see that each element has a range - and that the range is not the same for each. We say, "pH of 6.5 for soil and 5.8 for hydroponics," but the world will not end if we allow some variance (and it may actually be helpful).

The second option would be to start adding nutes on an ongoing basis, trying to maintain a certain nutrient level.

That, probably. I used to think that changing the reservoirs once per week, every week was the correct way to go, and that to do otherwise was lazy. Then I started thinking... Now, I have the feeling that this is a sign of laziness . After all, dumping/refilling does not exercise the brain.

People dump/refill their reservoirs to "reset" their plants' (nutrient solution's) nutrients, or to remove buildups of nutrients and waste products. Can't do anything about the latter, but if you understand - in a general way, at least - what is going on, that your plants are consuming more of certain elements... than adding back those particular nutrients becomes feasible. Unfortunately, our EC meters only give an overall picture instead of showing that, for example, your phosphorous content has dropped by 52 PPM. But using both meters and observation of the plants (along with the experience that comes from multiple rodeos) helps. You will probably gradually begin to get a feeling for what was consumed. Again, it helps that one's target is somewhat broad instead of a minute point.

Plants are remarkably resilient. I used to do reservoir maintenance and/or changes in the morning while I was waiting on the (then) OL to get ready for work. Used to drop her off on the way to my job. Then she got a job in the next town over... in the opposite direction. Then she admitted that the reason she wasn't driving herself wasn't for convenience (when her stop was on the way to mine) but, instead, because her license had been semi-permanently revoked before we got together :rolleyes3 . So my drive to work began with me driving 30 minutes in the wrong direction, then driving back past the house on the way to MY job. Reservoir maintenance took a beating, lol. Some nights I'd get home (after the additional one-hour drive), open the door, and I could hear the various oxygen supplementation devices (air pumps and aquarium power heads (highly recommend those!) ) just rattling away, lol, because they were no longer in solution - because the poor roots were barely damp. ... ... ... IDK how people using five-gallon buckets manage. One of my plants (at the time) would have transpired more than that in a day. Maybe our definition of monstrous is somewhat different? How many square feet does each plant's canopy cover? Five? Eight? Environmental conditions affect this, and my plants were in a hot, dry environment with LOTS of airflow, along with enough DO in the nutrient solution to keep a mouse from suffocating . Canopies were very nearly eight square feet per plant in "scrog" style growing, with reasonably long vegetative times (10 to 12 weeks, for the most part). Think I had approximately 62.5 watts per square foot of HPS light at the time. LOTS of white roots. I remember wondering if I could mix them 50:50 with spaghetti and eat them, but I never tried it.

I'm just jabbering. I had a point, but I seem to have lost it. Your plant's feeding actions appear to be normal to me. I think, on average across the entire spectrum of cannabis growers, that we probably pour more nutrients down the drain than our plants ever use. That bugs me on a fundamental level. Once upon a time, we depended on the natural yearly flood/drain cycles to replenish our farmland. Then we started adding fertilizer. Things seemed to be more efficient. After all, we grew more food, lol, and stopped worrying about whether the flooding would occur this year or not. <SCRATCHES HEAD> But look at the entire picture. Excess fertilizer (/pesticides/etc.) makes its way into the creeks/streams/rivers. Or down the drain and into the municipal wastewater treatment plant (a tour of which could be very educational, especially when one realizes that they don't exactly output pure water). Lots of money poured out in excess nutrients. LOTS of money spent treating the resulting contaminated water. Seems like a waste at every step. And then I turn on a faucet, fill a glass with water... and I cannot drink it. THEY should be paying me to accept this crap. But that's okay, it appears to be perfectly acceptable in quality to those in charge. They sure seem to drink a lot of bottled water, though....

 

[Scrogdawg]

An excellent read TS. Thanks.

 

[jackson1988]

TS my ppm is dropping while ph rises. This is normal and supposedly means they are using more nutes and need more. I let it ride up to 6.2ph before I add 5.5ph ro water.
As for monsterous ladies... Yes one girl is over 5' tall and about 4' around and the other is 3.5' tall and round. I agree totally that this is way too large for 5 gal buckets. Root mass is entire bucket. Next run I want to uses something much larger but I'm kinda lost as what to get. Any ideas?
Thanks

 

[gr0w]

Going to throw this in here. Chart helped me out, hopefully it can help your situation too.

 

[TorturedSoul]

Yes one girl is over 5' tall and about 4' around and the other is 3.5' tall and round.

NICE!

Root mass is entire bucket.

Not so nice, lol.

Next run I want to uses something much larger but I'm kinda lost as what to get. Any ideas?

You can get Rubbermaid totes in large capacities. They also come in a variety of colors, so you can get something dark to help prevent algae. I think mine were 23-gallon size (expressed in quarts, IIRC), but I might be off a gallon or so. Nice tight-fitting lid. I just cut a hole in the middle of the lid that was just big enough to partially insert a 24-ounce Solo cup. I put about 100 ¼" holes in the lower sides and bottom of the cup, and added a small plant and those expanded clay balls to the cup. Stuck it into the hole in the tote's lid... I had to hand-water for a few days because I was too lazy to bother trying to run the roots through the holes. Didn't take long for the first root to hit the nutrient solution - and then the race was on.

Get twice as many totes as you have plants and you can lift the lid off of one and transfer it to another when the plant is still small. Makes reservoir changes much easier. But then I got one of those little hand siphon pumps for transferring kerosene to space heaters and just started doing "pump-outs and rinse" because the plants were getting large.

I used a good quality air pump for each reservoir, with lots of airstone type devices. Things looked healthy. Then I made one of the only purchases I've made at ChinaMart, and put one of these into each reservoir:

Best $19.95 I ever spent. Comes with a tube you can add to the bottom if you like. Pumps water up from there and jets it out under that black deflector on the right (deflector can be aimed, I directed it across the reservoir and down). The act of doing so causes a great deal of air to get sucked through that little clear tube and mixed with the water (venturi effect, I think) . And then the race advanced to another level .

I also added a little H₂O₂ (hydrogen peroxide) most days for that little extra boost of O₂ . A highly-oxygenated root system is a happy root system.

You can get generic totes, too, but be careful. There's nothing like bumping a full reservoir in the middle of flowering and see the side crack. Thankfully, effective liquid capacity at that point was probably down to about 12-15 gallons, but that's still quite a lot of solution to pour all over your grow room floor. And fair warning - 23 gallons of solution (or even close to it) is HEAVY; it's not something to pick up, more like something to drag across the floor.

BtW, yes, the Solo cups were completely destroyed well before harvest. I did the "scrog thing," though, so the chicken wire screen that the plant had grown into completely supported the plant. They say those clay balls are infinitely reusable, but it would have taken all day to pick through the huge root mass in the reservoir, like an Easter Egg hunt. Besides, they come in those handy 50-liter bags....

 

[gr0w]

NICE!



Not so nice, lol.



You can get Rubbermaid totes in large capacities. They also come in a variety of colors, so you can get something dark to help prevent algae. I think mine were 23-gallon size (expressed in quarts, IIRC), but I might be off a gallon or so. Nice tight-fitting lid. I just cut a hole in the middle of the lid that was just big enough to partially insert a 24-ounce Solo cup. I put about 100 ¼" holes in the lower sides and bottom of the cup, and added a small plant and those expanded clay balls to the cup. Stuck it into the hole in the tote's lid... I had to hand-water for a few days because I was too lazy to bother trying to run the roots through the holes. Didn't take long for the first root to hit the nutrient solution - and then the race was on.

Get twice as many totes as you have plants and you can lift the lid off of one and transfer it to another when the plant is still small. Makes reservoir changes much easier. But then I got one of those little hand siphon pumps for transferring kerosene to space heaters and just started doing "pump-outs and rinse" because the plants were getting large....

Got some pictures of your setup?

 

[Skunkworkz]

Thanks Scientific! I'm going to take your advice and do 7 day res changes and add nutes between trying to keep numbers up. Going to run flora kleen before res change for a few hours to get rid of excessive salts also

The reason you change out nutrients is *because* the plants use them. That's how hydroponics works. If you add nutrients instead of water between changes you're going to fuck up the mineral balance in your reservoir & lock up your plants. Ph does flux, it's normal. What you described, is completely par for the course.
You'd be well served reading a book or three about how hydroponics works, asking here will frequently get you wrong answers like "continue topping off with full strength nutrients not water" was. No offense, Sci. . (Switch out nutes every seven days, was correct though.)
Also: You don't need to wipe your reservoir out or clean it between changes unless you're over feeding your plants. A good cleaning after harvest & you're all set. And flora-kleen is unnecessary when flushing plants-if you didn't fuck anything up by overfeeding then you don't have an excess of salts to flush & plain water is just fine. Just because someone makes a product that allegedly(!!) does a Thing, doesn't mean that it's not a waste of money.
Overthinking & over-doing, will cause as many problems as fucking off & being lazy. Or maybe even more.

️

 

[Scientific]

You'd be well served reading a book or three about how hydroponics works, asking here will frequently get you wrong answers like "continue topping off with full strength nutrients not water" was. No offense, Sci. . (Switch out nutes every seven days, was correct though.)

No offense taken, Skunk. If you will go back and look, you'll see that I was just making some suggestions for safe, reasonable ways to counteract falling PPMs, which is what the OP was concerned about.

There is no one, single way to do hydroponics, of course. To suggest that there is one "correct" method, specified by and agreed up on by one or three books, is to my way of thinking (forgive me) a rather narrow and simplistic view. If a particular method is working for you, that's great! Others may prefer to learn the principles and then experiment and improvise to develop variations that work best for them.

 

[Skunkworkz]

No offense taken, Skunk. If you will go back and look, you'll see that I was just making some suggestions for safe, reasonable ways to counteract falling PPMs, which is what the OP was concerned about.

.A way to "counteract unstable EC/ppm" (which his, are technically not) is to use coco, & run passive hydro by hand or drip feeding daily. Never any drift when nutes are fresh every feeding. But growing the way he does, recirc/buckets/tubs, ph drift & EC/ppm falling off as the plants feed, is completely normal and not cause to modify feeding..


There is no one, single way to do hydroponics, of course. To suggest that there is one "correct" method, specified by and agreed up on by one or three books, is to my way of thinking (forgive me) a rather narrow and simplistic view.

.Growing the way he does, one does not simply add fresh nutes to old ones without causing uptake problems. Period..

If a particular method is working for you, that's great! Others may prefer to learn the principles and then experiment and improvise to develop variations that work best for them.

.Hence my suggestion that he reads some books on how hydroponics & plant nutrition works, rather than trying to get concrete answers from a site that's populated primarily by newer growers. Who, while meaning well, probably shouldn't be speaking with much authority on growing weed..

 

[TorturedSoul]

There is no one, single way to do hydroponics, of course. To suggest that there is one "correct" method, specified by and agreed up on by one or three books, is to my way of thinking (forgive me) a rather narrow and simplistic view. If a particular method is working for you, that's great! Others may prefer to learn the principles and then experiment and improvise to develop variations that work best for them.

Yeah... I think that there is a lot of... People try a thing because their brother's girlfriend's father's favorite hooker tried it and, yippee, look at all the buds, lol - so it must be THE way to go. And then, well... Internet :rolleyes3 .

I won't say that it's impossible to kill a cannabis plant, because I have personally discovered several ways to do exactly that . But, like most plant species, cannabis is remarkably resilient. The stuff grows all by itself in environments that I wouldn't do well in. It doesn't take much to get "a" harvest. Anything over and above that, it's just fine-tuning (so to speak), along with things like the grower's personal preference, what fits his/her schedule, et cetera.

Unless you're chasing the one gram(+) per watt threshold, or the like. And even then, I've seen totally different growing styles (et cetera) all do very well.

Are some decisions more productive than others? Well, sure - in theory. But if doing certain things to increase yield (improve flavor, etc.) also has the effect of causing the grower to get lazy - or think, "I just don't have time right now," it can actually hurt performance. I mean... You can cook for two days straight to make the perfect meal (like my ex-wife's former boss' specially hired cook once did for a party) and come up with a simply fabulous meal. But that just doesn't fit some people's schedule (or personality, I suppose). If that was the only way to eat, some folks would surely starve to death.

I've done weekly reservoir changes, all the way through grows. I guess that at some point I realized my cannabis plants did not have access to my calendar, lol, so why would I expect them to require something be done every Tuesday evening between 4:30 and 5:00 pm? DWC hydroponics lacks the "buffering" that soil can provide, and I consider that to be a good thing. It means that when there's an issue, the grower is able to observe the effects almost immediately - and corrections can happen just as fast. As far as I'm concerned, DWC hydroponics is the perfect way to begin growing cannabis. The new grower doesn't end up doing 23 different things, seeing an issue, and wondering which of those things caused it. Ya screw something up in hydro and you see an issue before you have a chance to do much else. The example I like is adding too much silicon. Do that to your soil, you might have a week go by before you start seeing significant leaf shedding. Dump too much silicon into your DWC reservoir and you'll be sweeping up EVERY leaf the next morning. Instant understanding of what caused the issue .

I did a grow where I think I changed the reservoir three times during the entire thing. Would I advise a NEW grower to do this? Of course not, because he/she does not have the experience to know when an issue is just beginning. And I'm not exactly going to be looking over his/her shoulder the entire time. So we say, "Do this, it's safer." Don't drive 90mph on the Interstate, going 70mph is safer. That bump on your arm? Don't squeeze it, go show it to a doctor. Et cetera. It's just... Well, you cannot say "idiot-proof," because the universe has a habit of producing even better idiots, lol. But like that. If you do not understand... If you do not have the experience... Than do this thing, in this way - because it'll be safer.

But at the same time, if the new grower grows his/her cannabis like that - forever - then he/she will pretty much always have the skill set... of a new grower. You don't learn that way, you're just following a set of easy-bake oven directions. And that's cool, in the beginning. It probably keeps little kids from burning themselves on those little lightbulb-powered oven toys. However... It does NOT produce a master chef....

EDIT: (New post since I started typing...)

A way to "counteract unstable EC/ppm" (which his, are technically not) is to use coco, & run passive hydro by hand or drip feeding daily. Never any drift when nutes are fresh every feeding.

OF COURSE the EC isn't going to remain static, lol - regardless of the method of growing. Do you think your plants only feed when you're actively pouring the nutrient solution into those containers full of coco? No, they're sucking nutrients the entire time they're receiving and processing light-energy. The only time your EC won't be constantly falling is when you forget to put a plant in there (or if it has died, I suppose). Plants aren't like snakes, they don't gorf down a baby lamb and then go off to digest it for the next three weeks - feeding is much more a continual thing with them.

Some people like using a drip-feed setup. They aren't placing their plants on a starvation diet; they recognize the fact that their plants are constantly feeding. I just happen to recommend DWC, instead, primarily due to the much simpler setup and the ability to provide mad amounts of DO (dissolved O₂) to the roots.

Again, growing by rote is fine - if the grower is either a proverbial babe in the woods or has completed a few rodeos but has ZERO wish to learn.

I guess it's like that old saying, "Build a man a fire and he'll be warm for a day - but set him on fire and he'll be warm for the rest of his life." Err... Or maybe it was something about giving a man a fish vs. teaching him to fish .

 

[jackson1988]

"Well it looks like we got ourselves a reader" to quote Bill Hicks if you know who he is
I read... ummm let's see. .. almost constantly. But truth be told I haven't had the pleasure of reading a book on hydro. My fault. I am not new to this culture of ours but have had dirty fingers mostly with only one other hydro grow. I am nowhere near an expert but I try to learn everyday. I will take all advice here, shuffle it around in my brain, take a swag, and do only what I know works.

SWAG Scientific Wild Ass Guess... another quote from a great American. Carlos Hathcock

 

[jackson1988]

And now I feel kinda ignorant because I haven't read up on hydro so off to amazon I go. Plus I just inhaled a few "cough" puffs of a really fine sativa
Thanks bros. Stay safe and happy 4th !!!

 

[Skunkworkz]

And now I feel kinda ignorant because I haven't read up on hydro so off to amazon I go. Plus I just inhaled a few "cough" puffs of a really fine sativa
Thanks bros. Stay safe and happy 4th !!!

Just for fun...

GenHydro 3-part for Dummies

1/ Delete the Grow (green) bottle.
(See also: "Lucas Formula").

2/ 6ml micro, 9ml bloom per gallon @ 6.0-6.2ph
You feed this in veg, and flower, too. DWC, coco, ebb/flow tables, whatever. Easy. As. Fuck.

A 10 week cycle:
(Assuming your water is spring water @ .1EC or EC 0 if RO.)
****If RO water is used, add 3ml/gallon CalMag throughout entire grow UNTIL end of week 8. If using spring water in coco, use CalMag in the first month of veg, then delete.

Week 1-4:
6ml micro/9ml bloom, EC will be 1.2-1.3
(Fuck "ppm" as a measurement, it's for rookies) .

Week 5:
6ml micro/9ml bloom + kool bloom POWDER @ 1/4 tsp/gal. EC will be 1.3-1.4, ph should always(!) be 6.0-6.2

Week 6:
6ml micro/9ml bloom

Week 7 & Week 8:
6ml micro/9ml bloom + LIQUID kool bloom @ 10ml/gal in coco. ---> 5ml/gallon in DWC/buckets/tables.
EC @ 1.7-1.8 in coco, about 1.6 in DWC etc.

Week 9:
9ml bloom ONLY/gallon
(This tapers nutes off & starts the plant flushing)

Week 10:
Pure water at 6.2ph

Day 70:
CUT.


That's pmuch bulletproof.

 

[TorturedSoul]

I read... ummm let's see. .. almost constantly.

Me, too, lol. I'm a firm believer in "if you aren't learning, you might as well go ahead and punch out."

But truth be told I haven't had the pleasure of reading a book on hydro.

And now I feel kinda ignorant because I haven't read up on hydro so off to amazon I go.

You might try your local library. I was wandering through mine way back in the early- or mid-'80s and found a book on hydroponics. It wasn't huge, and the "pictures" were mostly just line drawings. But it even went into ordering the separate elements/minerals and mixing up your own hydroponic nutrients. There aren't many recent books that seem to cover such things. And that's a shame, because the related information - such as how adding some things in certain forms can cause other things to precipitate out of solution - can be very useful, even if one never intends to mix up his/her own nutrients from the individual components. And this book was published... in 1972 :rolleyes3 .

I guess it makes sense that (some small number of) books have been getting published on the subject of hydroponics for decades. After all, the practice of using hydroponic growing methods has been around since... How long ago did the Hanging Gardens of Babylon exist, lol?

Plus I just inhaled a few "cough" puffs of a really fine sativa

Congratulations. Wish I was there .

happy 4th !!!

You know... For what is almost certainly the single most important holiday in our entire country's history, it's surprising how many people don't know that it's called Independence Day. (I guess they think it's a movie title or something, lol?) Funny, but I don't believe I've ever heard someone say, "Hey, you have yourself a happy December 25th, now. And I'll see you a few days after that for the big January 1st Eve blowout!" :rolleyes3

Yeah, I'm a bit of a smart@ss. But, still...

Lots of tutorials and information on hydroponics

I make it a practice not to give my support to anyone who refers to cannabis as "weed" or any other of the more unsavory nicknames. Cannabis prohibitionists do that - and I don't feel that they need my help. But that's just me, I guess....

 

[TorturedSoul]

GenHydro 3-part for Dummies

1/ Delete the Grow (green) bottle.

That's pmuch bulletproof.

Unless you happen to go in for long vegetative periods, in which case you end up giving them way too much phosphorous, since there's approximately five times as much phosphorous in the Bloom component than in the Grow (the Micro, AfaIK, doesn't have any).

Just another example of why one method doesn't work best for everyone.

I have used the Lucas formula and other versions, since I once used General Hydroponics nutrients almost exclusively. But there are situations where it can be contraindicated.

 

[Scientific]

You feed this in veg, and flower, too. DWC, coco, ebb/flow tables, whatever. Easy. As. Fuck.

Thanks for sharing that Skunk. I have saved it in my formulary for further consideration.

Easy is a good thing, but it's not the only thing. Those who are willing to fuss with concentrations a little more should be able to get higher yields. It would be interesting to do a side-by-side grow test.

(Fuck "ppm" as a measurement, it's for rookies) .

I agree that EC makes better sense, but so does the metric system. Just as if you happen to be living in one of the backward countries that still uses imperial units, you'll communicate better in pounds and inches, when you're on a forum that uses mostly PPM, it makes sense to use that. And unlike converting between imperial and metric, you can convert between EC and PPM with one simple mathematical operation. Easy. As. Fuck.