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Lucas Formula Defined/Explained

E

eidanyosoy

I have had this on my computer for a while I hope it helps some of you, this is what I have followed for years.

General Hydroponics Flora Series Feeding Strategy - Lucas Formula

G-M-B (Grow-Micro-Bloom)
0-5-10 - For Vegetative cycle (18/6)
0-8-16 - For Flowering cycle (12/12)

The numbers above indicate the number of milliliters (ml) of Flora Grow, Micro or Bloom formulas that I use in one gallon (US Liquid) of nutrients.

You will notice I dont use any of the Flora “Grow” formula, do not need to, the Flora "Micro" provides plenty of Nitrogen.

There are two ways to work with this formula:

1. Top off the reservoir daily using a pH corrected water solution as required to maintain full reservoir level. After adding back an amount of water equal to the amount of your reservoir capacity you should change the reservoir and put in fresh solution.

2. Top off the reservoir daily using a pH corrected 100% strength nutrient solution as required to maintain full reservoir level. Continue to use this nutrient solution without dumping the tank unless the PPM rises above acceptable levels.

Between vegetative and flowering cycles you should dump your nutrients, then flush (possibly with Clearex) to remove salt buildups, then change to the other feeding program. Always shake your GH nutrient bottles before using them!

For young plants, just transplanted into the hydro setup, give them 50% strength nutrient mix to prevent overfeeding them while their young. Gradually bring up the mix to full strength as they grow over the next few weeks or so.

The lucas formula is normally intended for use with RO or near 0 PPM water.

NOTE: The Lucas formula eliminates the need for Epsom salts to correct (Magnesium) Mg deficiencies in most normal feeding programs recommended by manufacturers. Cannabis needs a lot of Magnesium to thrive.

The Flora Micro is providing the Nitrogen and the Magnesium in the proper balance, thus there is no need for the Grow formula and little or no room under the maximum acceptable ppm limit of 1600 @ 0.7 conversion.

Calculated EC/TDS levels:

EC microsiemen:
0-4-8: 946 µS
0-5-10: 1184 µS
0-8-16: 1894 µS

TDS @ 0.5 conversion:
0-4-8 = 473 ppm
0-5-10 = 592 ppm
0-8-16 = 947 ppm

TDS @ 0.7 conversion:
0-4-8 = 663 ppm
0-5-10 = 829 ppm
0-8-16 = 1326 ppm

Addback Calculator - (For Advanced Users)

Say you were running the 0-8-16 formula, at 0.7 conversion with a 22 gallon res. When you first fill it up, your ppm will be around 1330.

Now you have been growing for a week, and some of the water has been taken up by the plants, some has evaporated, and now your res is at 947 ppm. You need to get your ppm from 947 to 1330. Here is the equation:

((target - current) / target) * 8 ml per gallon * res gallons = Flora Micro (ml) double this figure to get Flora Bloom (ml)

Example:

((1330 - 947) / 1330) * 8 * 22
(383 / 1330) * 8 * 22
0.3 * 8 * 22 = 53 ml Flora Micro

53 ml Flora Micro, double that and you get 106 ml Flora Bloom. So 53 ml Flora Micro and 106 ml Flora Bloom to add back to your 22 gallon res to get you from 947 to 1330.

Using Hard Water GH Micro

I had been experimenting with using the Hard water Micro as a substitute for the normal Flora Micro, this to account for my hard 350 PPM water and the lack of a large enough RO filter at the time. It has worked well for me. I just kept my reservoir below 1150 PPM @ .5 conversion and its all good.

One tip - do not pH down this stuff, the hard water micro will drop pH gradually over the next 24 hours, for example I mix up a batch, it is at like 6.2, the next day, its at 5.6-5.8 after running in the system for a while. If I pH downed that to 5.7 before putting it in the system, it ended up as low as 4.8-5.2 by the next day.

My conclusion, the hard water micro was buffering the alkaline crud in my water, it just doesnot do it ASAP fast like the phosphoric acid.

Now, the floranova bloom is basically the Lucas Formula in one bottle. 5 ML/gallon is equivalent to the 0-5-10 and 8ml/gal is equal to the 0-8-16.
Don't forget the 5ml per gal of floralicious bloom, thats if you want frosty flavor. That is the other part of the Lucas ratio using floranova. I am completely satisfied with the fnb/flb combo, but -on a new gallon, pour out the floranova and stir several times over a period of a couple hours then rebottle and the regular shaking before use will keep ya good. Anybody who does this will see why I recommend this, you ain't gonna get it remixed by shaking the bottle only.
:spank:
 
D

dongle69

eidanyosoy said:
Don't forget the 5ml per gal of floralicious bloom, thats if you want frosty flavor. That is the other part of the Lucas ratio using floranova.

Just to clear things up, Lucas formula has nothing to do with Floralicious Bloom.
It is Floranova Bloom only. No additives whatsoever.
 

Haps

stone fool
Veteran
OK, first there is a sticky above here, from Lucas, from those interested. I do not know what he says these days, but I got 4 years + of experience with his ratio. D69 is completely wrong. The ratio is a base methodology that will deliver a good crop in a simple fashion. Much of the lore around it is incorrect. You do still need cal mag, with over 80% of the strains I have tried, a few like the ratio as it is. You DO need floralicious bloom if quality and flavor is important, and it is. And after starting the crop at full ratio, you add back at one third nutes / two thirds clear water. You will improve your yield if you change the res along the way at least once, and that is not part of his gig.

I still mix my nutes at Lucas's ratio, but I have fine tuned my use of it, through experience in my tuning process. There is no one right way.
H
 

Hydro-Soil

Active member
Veteran
Haps said:
OK, first there is a sticky above here, from Lucas, from those interested. I do not know what he says these days, but I got 4 years + of experience with his ratio. D69 is completely wrong. The ratio is a base methodology that will deliver a good crop in a simple fashion. Much of the lore around it is incorrect. You do still need cal mag, with over 80% of the strains I have tried, a few like the ratio as it is. You DO need floralicious bloom if quality and flavor is important, and it is. And after starting the crop at full ratio, you add back at one third nutes / two thirds clear water. You will improve your yield if you change the res along the way at least once, and that is not part of his gig.

I still mix my nutes at Lucas's ratio, but I have fine tuned my use of it, through experience in my tuning process. There is no one right way.
H

You know it Haps.......

Running LF myself. Love it, preach it.
Cal mag does indeed depend on strain.
My SK#1 doesn't need it.
My Princess Diesel wants a little bit.


0-5-15 is not veg formula!

Lucas recommends the 0-5-15 for low intensity light grows. Like Flouros and low-level intensity CFL grows.

The only time I switch from the 0-8-16 formula is I use 1/3rd str when feeding seedlings. Even then they jump up to eating full str quickly.

Personally I'm planning future hydro grows around The FloraNova Bloom at 8ml per gallon.

Lucas does not recommend any additives of any kind when using the Lucas Formula. He notes that others have mentioned Cal/Mag deficiencies when running RO water but that he's never run across it himself.

The Lucas Formula DOES have a enough nitrogen in it to create some wonderful algae blooms. Please be sure to thoroughly light-proof and insulate your res. :bashhead:

Top off with pH adjusted water? Not if you're using RO water.

Where did you get this eidanyosoy??????????
 
D

dongle69

Haps said:
D69 is completely wrong.

I'll reiterate again, Lucas formula has no additives whatsoever.
Never has.
Not talking a right or wrong way to grow, just Lucas formula.
Lucas is only GH FloraNova Bloom OR GH Micro + Bloom (or anything that matches the nutrient profile).
Nothing else. Ever.
That is Lucas formula.
No additives at all.
Could it be any more clear?
Additives?
No.

Anything else you want to add is fine, it just isn't Lucas formula.
 
Last edited:

FreezerBoy

Was blind but now IC Puckbunny in Training
Veteran
It's a strain thing. Last grow said 0-3-6 was too strong. This grow says 0-5-10 is too weak. I'm sure Lucas is a nice guy, kind to animals but, I'm listening to my plants. It's why we bought those fancy meters in the first place.
 
I

igrohydro

You must spread rep before giving it to freezer boy again. :joint:
 
Haps said:
OK, first there is a sticky above here, from Lucas, from those interested. I do not know what he says these days, but I got 4 years + of experience with his ratio. D69 is completely wrong. The ratio is a base methodology that will deliver a good crop in a simple fashion. Much of the lore around it is incorrect. You do still need cal mag, with over 80% of the strains I have tried, a few like the ratio as it is. You DO need floralicious bloom if quality and flavor is important, and it is. And after starting the crop at full ratio, you add back at one third nutes / two thirds clear water. You will improve your yield if you change the res along the way at least once, and that is not part of his gig.

I still mix my nutes at Lucas's ratio, but I have fine tuned my use of it, through experience in my tuning process. There is no one right way.
H


Pfff...Why spread crap like this Haps? Lucas says no additives ever never ever. I still have a full bottle of cal mag cause I listened to people like you way back in the day. I have never had 1 single problem with Floranova mixed at 8 ml a gallon. I don't even use ph up or down. I add nutes as I need to adjust ph.

People just read the Ask Lucas thread at Cannabis World. It is just pure gold. There is alot of techy shit in there but there is way good info on HIS formula coming from Lucas' mouth.

Floralicious for taste and quality....FAIL. Try strain and environment.
 
E

eidanyosoy

Ok Ok

Ok Ok

I agree with Haps I have ran LF with and without the floralicious, it definitely helped the flavor, a lot actually. I have never had a need to use Cal mag as I don't use RO. I forgot where I got this info from to be honest.

"0-5-15 is not veg formula!" umm yeah it is this is his old formula has always worked just fine for me. 5 ml a gallon of FNB. He has recently changed it to be 8, but why use the extra nutes, which are 90 bucks a gallon if its not needed?

And to whoever said "his" formula referring to lucas is incorrect. Though it may be named "Lucas Formula" it was in fact created by "pH" Lucas' guru. But thanks for chiming in lol.
 

Hydro-Soil

Active member
Veteran
eidanyosoy said:
"0-5-15 is not veg formula!" umm yeah it is this is his old formula has always worked just fine for me. 5 ml a gallon of FNB. He has recently changed it to be 8, but why use the extra nutes, which are 90 bucks a gallon if its not needed?

And to whoever said "his" formula referring to lucas is incorrect. Though it may be named "Lucas Formula" it was in fact created by "pH" Lucas' guru. But thanks for chiming in lol.

The Lucas Formula covers both veg and bloom with one "formula"
0-8-16 3part GH or 8ml/gal Floranova Bloom. No additives.

There is nothing about vegging in the Lucas Formula.
Lucas DOES have recommendations for alternative vegging formulas but they're suggestions and not part of the "Lucas Formula"

Lucas said:
> is it ok to simply raise the tds of an 0-5-10 rezup to the target tds of 0-8-16 when flowering is initiated, rather than dumping the rez of 0-5-10

yes, if you are vegging in 0-5-10, you can certainly just add more nutes and keep going, by raising the TDS.

imvho, there is no need to dump the veg res

Im glad you asked about that, because Ive been meaning to talk a bit about vegetative nutes.
btw, before I blaze ahead, I dont recommend 0-5-10 as a veg formula actually, I only recommend it as a low light formula..

:asskick:

And I'm fully aware of the formula being pH's and have mentioned it several times before. People don't listen though. They tend to repeat what they thought they heard and read.

If you like I'll pull more excerpts from his 36 page thread on the subject.
 

one Q

Quality
Veteran
So based on Lucas quote above, it seems that the formula at full strength is for, maybe 600w and up.

This makes sense that Freezer Man is needing lower ratio b/c he's only using 250 (and killing it, I might add.) Freeze, I bet that if you had 400, or 600 you'd end up with a higher ratio closer to 8/16, but still taking the into account the "strain factor."

I wonder how all this adds up when using the Gr3atfulH3ads version for coco coir.
 

FreezerBoy

Was blind but now IC Puckbunny in Training
Veteran
one Q said:
Freeze, I bet that if you had 400, or 600 you'd end up with a higher ratio closer to 8/16, but still taking the into account the "strain factor."
You may be right. Still, you'd need to test to be sure. I doubt grinding up the chart and mixing it with water would yield meaningful readings. Following the chart may get you vaguely close (or it may fry you to death). EC readings of the res will tell you exactly what the plants want.
 

Hydro-Soil

Active member
Veteran
one Q said:
So based on Lucas quote above, it seems that the formula at full strength is for, maybe 600w and up.

He's actually speaking about flouros. I've used his formula under 150w HPS lamps, without issues, with several different strains.


Are you guys shaking the bottles properly before mixing your nutes? I'm thinking this might have something to do with why different people get different results sometimes. Weird.
 

VenturaHwy

Active member
ICMag Donor
Veteran
Does any one have the ppm of all of the elements in the Lucas nutrient solution, I just wanted to compare it to the formulas that I make. Either ppm in the final solution or percentages of the concentrate.... I went to Ask Lucas, I didn't see anything... curiosity is all...
 

kaljukajakas

Active member
The 8 ml GH Micro + 16 ml GH Bloom composition (micros omitted) should be:

N 130 ppm (122 ppm nitrate + 8 ppm ammonium)
P 106 ppm
K 183 ppm
Ca 130 ppm
Mg 73 ppm
S 49 ppm

What formulas do you make, VenturaHwy?
 

Blunt_69

the keeper of the creeper
Veteran
woah....woah....woah....dang.... talk about a whole lot of advanced jabber on lucus formula.... simple guys simple!!!lol!!!OK lucus formula is A RATIO...nothing more nothing less.. No diffrent then then the formula RATIO, printed on the bottle..

My experiance with the "lucas formula"

I use 5/10 ml in veg. That is unless i see a change in my meters.Then i bump it up to 8/16ml.Alot of people run 8/16 in veg under HPS/MH.Generally.. this RATIO sits very stable in my system at 550PPM~600PPM. I call this my BASE nutrient profile. For those of you wondering i use a one 1k HPS.

I also use HYDROZYME along side the BASE profile as an "additive", throughout veg and flower at about 10ml per gallon.

Flower. Base profile changes to 8/16ml per US gallon, or my case 4-liters of water.

This takes the rez into 1000~1100PPM range. I also use a bloom "additive" along side my BASE profile in mid to late flower and generally downshift 8/16 to 5/10 in flower when using the bloom enhancer. My system recirculates, and I do not flush frequently, so these changes do not reflect in huge flucutations PPM wise in my system.I do limit to 1400PPM in flower as a MAX. I do not use cal mag. I also seem to run a bit higher PH where 5.9~6.2 is normal.

Lucas formula - ie. Base profile seems to work excellent in a recirculating hydroponic system.
 
K

kokua

Blunt_69 said:
woah....woah....woah....dang.... talk about a whole lot of advanced jabber on lucus formula.... simple guys simple!!!lol!!!OK lucus formula is A RATIO...nothing more nothing less.. No diffrent then then the formula RATIO, printed on the bottle..

nah man your crazy...lucas formula is a state of mind bro :bashhead: lol

B69 is right...it's not that difficult. Its a simple 2-1 ratio for base nutes...how difficult do we really have to make this? lol Use whatever addatives you want to with it. I would definately recommend a few.

Lucas doesn't recommend any because he is trying to keep things simple. Why not it works. With a few addatives though...it works a lot better.

The first thing I would add would be hygrozyme. It's amazing stuff. If you don't know about it...do a search, there is a lot of info on this board.

The second would be a humic/fulvic. Any time you use mineral salts you should consider using humics/fulvics for their chelating effects. Chelating agents like humics/fulvics are going to help keep the salts from precipitating and turning into salt residue and they are going to help the plants take in the nutrients your giving them much more efficiently. Effeciency is everything.

The third would be some kind of seaweed or seaweed based bloom booster. Some have mentioned flor+, I like using plain old seaweed, nothing fancy.

Notice that none of those addatives are nutritive. None give the plants any additional nutrition. One is enzymes, the other is organic acids, the other is seaweed with low amounts of nutrient. The 2-1 formula is base nutrient.

I am sure there are other suitable variations and additions that can be made to the simple 2-1 'lucas' gh formula.
 
D

dongle69

Better yet, use FloraNova instead of the standard Flora multi part series.
Only one part, cheaper to use, and already has humic acid.
 
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