Can someone explain this LUCAS so called FORMULA to me...

[10k]

Wait...What wrote...

Does anyone know who originally did the research on that graph? I've seen both Cornell and Stanford cited. Everybody rips it off but nobody gives credit where its due (including the company that used it commercially on the bottle of pH UP)

Afaict, I believe it originally comes from the book "Hydroponic Nutrients" by M. Edward Muckle.
Its a book about chemical salts type hydroponic nutrients, this book has been respected and used as "the bible" in the hydroponics growing world for decades.
The charts appear on page 100 in that book according to this GrowFaq .

http://www.drugs-forum.com/growfaq/73.htm

 

[10k]

I'm not sure what I learned yet.. but I may a little more confused...

I may NOT go with the LUCAS formula.. Since the MaxiBloom and MaxiGro is similar...

Let me tell you what I have been doing.... lol

from blazeoneup
Indica's
Seedlings and clones 300-400ppm 5.3-5.5 ph
early vegg 500-600ppm 5.3-5.6 ph
middle vegg 600-800ppm 5.4-5.6 ph
late vegg 800-1000ppm 5.5-5.7 ph
early flower 1000-1300ppm 5.5-5.7 ph
middle flower 1400-1600ppm 5.5-5.8 ph
late flower 1000-1100ppm 5.5-5.7 ph
ripening 300-500ppm 5.4-5.6 ph

sativa's
seedlings and clones 250-350ppm 5.3-5.5 ph
early vegg 300-500ppm 5.3-5.6 ph
middle vegg 500-700ppm 5.4-5.6 ph
late vegg 700-900ppm 5.5-5.7 ph
early flower 1000-1100ppm 5.5-5.7 ph
middle flower 1100-1300ppm 5.5-5.8 ph
late flower 800-1000ppm 5.5-5.7 ph
ripening 300-500ppm 5.4-5.6 ph

at this thread....
http://icmag.com/ic/showthread.php?t=26343

I always NEED phUP..... I don't think I can do without it.... I use RO water and MaxiGro and set the pH settle ... usually it starts off well and no ph adjustment is needed (maybe 5.5?) Within a few days the ph DROPS (down) so I add phUP or else it will go down to 4.something...... Sometimes I bring it to 5.8 so it will drop down to 5.2 in case I am not home for a few days...and slowly add more nutes as the plant develops... and change RES. when I go into bloom with new RO water.. and New Nutes... Now sometimes I get deficiencies... maybe it is sometimes I let my system pH drop too much because I am not around... (a GREAT system auto top off and all but no auto PH adjustment)... so i wasn't sure what the def. was from... maybe the few days I slacked on pH.... but that's why i was looking into Lucas formula.. but I would think it would be impossible to NOT add phUp..... My plants usually LOOk great through VEG... it's that 2 months in bloom that I have a little problem.. I get over 1lb on a 1000 watt lamp... are leaves supposed to die? alot? I add phUP and nutes straight to the Res. (that maybe a problem now from reading?)

It's best to let your plants tell you if they're hungry or if they're getting a little too much by observing how they're reacting to the current feeding levels. Your continuous need to be upping the pH could be just that the plants are drinking in more water than nutes. This will have an effect on the operating reservoir strength which in turn can make the pH drop. In other words, the auto topping off drum (the refill solution reservoir) needs to have a weaker nute solution for the current stage of plant growth or consumption rate.

The topping strategy of always adding nute solution, always needs to take into account that there will always be some need to replenish the water losses, thus any refill solution needs to be at a considerably lower strength than the working reservoirs starting strength.

Said another way, if your auto topping drum is topping the dwc stations and control bucket (reservoir) with the same strength chem nute solution, then no wonder it's pH is dropping all the time.

The one good thing about your auto topping system, is that your system is topping the working reservoir with a pre-mixed chem nute solution instead of the very flawed practice of adding nute chem nute concentrates to an already mixed chem nute solution...thus avoiding the element 'damage' many folks end up doing to their working reservoir solution.


I love those nute strength guidelines from that blazeoneup thread btw.
In the lucas ratio, imnsho, there is no one set strength to stick with, but rather just follow the lucas flora series 'mix ratio' of one part micro to every two parts bloom, and let the plants tell you what they're needing. Folks with a lot of light intensity will find that their plants can consume a lot more strength than those same plants could ever consume at lower light intensity. Another reason that there is no single "best" mixing strength for these custom gh flora mixes, or any other chem hydro nute mix for that matter.

I like to see the plants not having any burning at all, but many growers try to push their plants growth rates, by upping the strengths gradually to the point where they are seeing some slight tip burn on the foliage, then backing it off slightly to find that ultimate super-feeding level.

Ime, running to the point of "greenhouse tip burn" like described above, is just asking for problems from pushing the plants to build up too much in their systems, like mr Bugbee's fat sick dog metaphors. I'd rather have the plants take from their built in food stores a few times along the way to tell me when to up the strengths....and change out the working reservoir on a regular basis to keep them on a healthy path.

I'm also an advocate of running some silicone additive in the water which helps with the overall pH stability (not to mention the plant benefits of silicone) of the mixed solution. But it needs to go into the water before anything else, then be pH'd down to about 6 before using this water for a basis to mix your gh flora cocktail (lucas in this case). potassium silicate alone is a very strong pH up and should be prediluted with water if you're going to use it as a pH up adjuster to avoid solution damage from running the pH up above 6.5 (where things really go haywire in chem solution mixes)
Same goes for anything you add to your already mixed nute solutions, pH down for example always pre-dilute it considerably with water first, before adding it to the mix.

This redundant note from the department of redundancy department...to avoid causing slight to severe element precipitation damage to your chem nute cocktails, always premix your chem nute topping off solutions before adding them to an existing mixed chem nute solution. Never add gh flora chem nute concentrates to existing mixes. Pre-dilute your pH adjusters and other additives before adding them to the cocktail and change out the entire reservoir on a regular basis. I prefer every two weeks at least, but other risk takers may try going longer...that's their perogitive not mine.

Turbolaser4528 wrote...

I think giving the plants less food sometimes would make it grow better, kind of like not always keeping it full but hungry for more!!! if you know what I mean, although I believe 680 is starving them, my hanna meter tells me otherwise so I dont know man.

I like your thinking turbolaser, feed them well, but don't over do it.

hth,
10k

 

[sexybudandnugs]

Well I auto top with RO water/AC water.... The portable AC has water with 1ppm so I let it drip in the res. Most of the water comes from the RO container... Are you saying I should put the nutes in the RO container? I do nutes and pH into the res.

 

[One Love 731]

10k, I have been flowering now for about 20 days lucas, drip, hydoten my water is @ 200 ppm 0.5 conversion and my rez has been at 1050-1100 ppm with 5.9-6.1 pH. I have already had the cal deficiency @ 3 weeks I fixed it with cal mag and a top off. I am about to do a rez clean and change out when adding nutes after diluting them, should I set my PH @ 5.2-5.3 or would that stress the plants, going from 6 to 5.3? Also is it a good idea to run plain PH'd water through the system for say a half hour before dumping and adding a clean nute and water solution?

To all of you:How come when I put 2ml micro, 4ml bloom pr liter (same as 8/16 pr gal) into the gh calculator it only gives me a ppm of 681? I thought Lucas was 947 ppm @ 0.5 conversion?

Karma, One Love

 

[10k]

10k, I have been flowering now for about 20 days lucas, drip, hydoton my water is @ 200 ppm 0.5 conversion and my rez has been at 1050-1100 ppm with 5.9-6.1 pH. I have already had the cal deficiency @ 3 weeks I fixed it with cal mag and a top off. I am about to do a rez clean and change out when adding nutes after diluting them, should I set my PH @ 5.2-5.3 or would that stress the plants, going from 6 to 5.3? Also is it a good idea to run plain PH'd water through the system for say a half hour before dumping and adding a clean nute and water solution?

Its never a good idea to make big jumps in pH all at once so you avoid a pH shock. Better to lower it gradually by a couple "tenths" every few days until you arrive at the input pH you'd like to run them at. For example : I'd go from that 6.0 average down to @ 5.8 for a few days, then bump down to 5.6 a few days then lower to @ 5.4 etc...

You said "drip" so I have to guess its something like a gh waterfarm, recirculating from a bucket to a drip ring onto the rocks. In this case its always good to flush off the rocks every time you change the bucket or res, because the rocks will get a salts build up over time being top fed with mineral salts nutes. Also if you are doing your regular top-offs or add backs with pre-mixed nute solution then it would also be "a good thing" to pour them into your water farm through the rocks to also help flush away the excess salts between res bucket changes.

For a small ebb&flow system for example. Pour some water over each rock filled net cup or planter to help get that salt rinsed off the rocks and follow it up (after dumping that water out of the res) with a fresh res change and flooding (feeding) to restore the fresh nute solution to the rocks n' roots at the running input pH the operator is currently running. A large e&f system is impractical to try to flush off each planter by hand and much easier to just flood the entire tray with pH'd water and run a flood at a slightly higher than usual flood height to help carry away the salts buildup before dumping it and following it up with a re-done fresh res mix and fresh feeding with normal flood height set as usual.

Well I auto top with RO water/AC water.... The portable AC has water with 1ppm so I let it drip in the res. Most of the water comes from the RO container... Are you saying I should put the nutes in the RO container? I do nutes and pH into the res

Oh, I was under the impression you were running a system just like the blazeoneup system which has a "topping res" on a float valve to top off the working reservoir. But either way, it's much better to mix your nute "refill solution" in a separate vessel and use it for your res maintenance topping solution.

 

[delta9nxs]

hi, one love 731

hi, one love 731

1 gallon is 3.785 liters. by using liters and not quarts you are creating a more dilute solution. later

 

[fatigues]

1 gallon is 3.785 liters. by using liters and not quarts you are creating a more dilute solution. later

Slightly, yes. In metric, the math is:

G-M-B (Grow-Micro-Bloom)
0-5-10 - For Vegetative cycle (18/6) 0-13.2 – 26.4 for 10 litres
0-8-16 - For Flowering cycle (12/12) 0-21.1 - 42.2 for 10 litres
For 1 litre, simply divide by 10, or 2.1ml and 4.2 ml, during 12/12.



You did sound a little unappreciative of the reason the poster uses his Lucas ratio expressed in per litres.

Quarts, pints, gallons... I don't think most Americans understand that there is no common-sense or intuitive understanding of just how much that is to those who were raised in the metric system. Might as well call a gallon a slartybart - it means as much to me (which is to say, it doesn't mean anything at all).



A litre? I know exactly what that looks like and how much volume of water that is. I can eyeball a litre pretty well.

A gallon? A quart? Not a chance.

 

[lysol]

Its never a good idea to make big jumps in pH all at once so you avoid a pH shock. Better to lower it gradually by a couple "tenths" every few days until you arrive at the input pH you'd like to run them at. For example : I'd go from that 6.0 average down to @ 5.8 for a few days, then bump down to 5.6 a few days then lower to @ 5.4 etc...

Hey 10k, I have been lurking and reading your posts. I tend to read threads over and over in an effort to try and get stuff to sink in, as to not let it go over my head. I am starting to understand a little bit what you are saying, I too was using that bad PH chart, and was dumping chemicals straight into my buckets without pre-diluting. That will all change.

When you say to PH down slowly, I admit I am a little confused how that inter operates with a 5.2 starting rez. So my current understanding is

1) start at 5.2PH
2) when PH reaches 6.0, do a full change out to reset to 5.2 / PH back down to 5.2 with top-off water

so you do a jump from 6.0 to 5.2

or do you PH down the old solution for a few days before your change outs to 'signal' to the plant PH is going to drop?? Do you just want an upwards swing and a sharp reset between the upwards swings? Or do you want to rock the PH back and forth like a wu tang concert?

If I had my nutes right I guess I would get a back and forth gentle rocking naturally, but lets say you aren't that tuned in yet or your PH rises due to high oxygenation or root problems, or some other problem not related to feeding strength, would you try to artificially create a gentle rocking or just deal with sharp resets?

 

[ultima]

Maybe im doing this all wrong but here's what works for me (at the moment).
Using Lucas and GH nutes.

0-8-16 into 21 gallons of tap water Ph 8 - 64 ppm.

This brings the EC to 2.2 or 1408 ppm - minus the 0.1 Ec/64ppm from tap = 1344ppm

Nutes seem to bring the Ph down to about 5.6 or just below 6 - (using PHdrops).

Then I top off with tap water for a few days or until i have replaced 20 liters/5.2 Gallons.
After replacing the 20l the EC is at 1.7 and the Ph has risen somewhat.
Then i use the addback calc to add 33ml Micro - 66 Bloom and Im back to the 2.2 Ec and the right PH.

I dont use any Ph down, I let the nutes bring it down.This is probably highly dependant on your water supply. Im a noob btw.

Now , I dont know for sure if its a safe way to do this but seems to be working for me.

 

[furley]

Ultima, do you replace the res after 5.2 gallons or 20 gallons? I thought it was when the size of your res gets added back?

 

[Hydro-Soil]

Ultima, do you replace the res after 5.2 gallons or 20 gallons? I thought it was when the size of your res gets added back?

He's topping off the res for a few days before adding nutes to adjust it back to his target EC. Not replacing the res.

 

[REZDOG]

It's funny.
People take a simple recipe,and over-complicate it,then wonder why it doesn't work,"as advertised"....


Duh.

 

[2fast4u2]

here here