Hello all, I have just bought & installed a reverse osmosis machine & want to use the lucas formula to try and ensure a balanced ph level (live in a hard water area).
But the recommended EC level is 1.9 for this formula which i can't go up to as i'm growing sea of green in a vertical system & as my plants only grow to approx 8 - 10 inches tall & they can only really handle an EC of 1.0.
Normally i start off with an EC of 0.6 & go up tp 1.0 over approx 10 days as there growing (5-6 days of veg).
Question: So can i adjust the formula so i'm getting an EC of 1.0 which is max strength for my plants ?
EG 0-3-6 instead of 0-5-10 - Or would this alter my ph levels too much ?
Full Version: Lucas Formula Question
wasn't familiar with the lucas formula and having just skimmed it on google i find it a tad complicated.
i don't understand why you can't reduce your EC, can't you use less ingredient to water or just add more water to the mix.
i have a similar system to you and try to run with an EC of around 1.6 (corrected). i did an experimental grow where the EC got to 2.5 before the plants started to suffer but find that they will take all sorts of nutrient abuse before they complain.
i don't use RO but when i use rainwater i have to add tap water in a ratio of about 1 to 5 to keep the pH stable.
have you got an EC meter?
i don't understand why you can't reduce your EC, can't you use less ingredient to water or just add more water to the mix.
i have a similar system to you and try to run with an EC of around 1.6 (corrected). i did an experimental grow where the EC got to 2.5 before the plants started to suffer but find that they will take all sorts of nutrient abuse before they complain.
i don't use RO but when i use rainwater i have to add tap water in a ratio of about 1 to 5 to keep the pH stable.
have you got an EC meter?
Yeah i have a bluelab trucheon (EC, CF, PPM) & i have read of other people just adding tap water to try & solve the ph buffer problem, But i was hoping to not have to add any tap water as my vertical system is getting salt & calcium deposits on it form my tap water.
I got the ro system to stop all the salt / calcium deposits & also it should be better for the plants aswell.
I got the ro system to stop all the salt / calcium deposits & also it should be better for the plants aswell.
I just use a ratio of 1 micro to 2 bloom on my res and when I top up.
using formula of
((current EC/target EC) * 1.05 * res size in liters)/2 to give your micro amount and double it for bloom.
or change 1.05 to 4 if you want to work in gallons for res size
For your per gallon just half it ie 4ml instead of 8 and 8ml instead of 16 as you are working at half the ec but I assure you you will want it stronger, mine are at 2.1 EC and it drops every day, I also add 1 tsp of epsoms to my res as I'm finding the lucas formula to be slightly mg light.
using formula of
((current EC/target EC) * 1.05 * res size in liters)/2 to give your micro amount and double it for bloom.
or change 1.05 to 4 if you want to work in gallons for res size
For your per gallon just half it ie 4ml instead of 8 and 8ml instead of 16 as you are working at half the ec but I assure you you will want it stronger, mine are at 2.1 EC and it drops every day, I also add 1 tsp of epsoms to my res as I'm finding the lucas formula to be slightly mg light.
QUOTE(snadge @ Oct 11 2008, 04:26 PM) 
I just use a ratio of 1 micro to 2 bloom on my res and when I top up.
using formula of
((current EC/target EC) * 1.05 * res size in liters)/2 to give your micro amount and double it for bloom.
or change 1.05 to 4 if you want to work in gallons for res size
For your per gallon just half it ie 4ml instead of 8 and 8ml instead of 16 as you are working at half the ec but I assure you you will want it stronger, mine are at 2.1 EC and it drops every day, I also add 1 tsp of epsoms to my res as I'm finding the lucas formula to be slightly mg light.
using formula of
((current EC/target EC) * 1.05 * res size in liters)/2 to give your micro amount and double it for bloom.
or change 1.05 to 4 if you want to work in gallons for res size
For your per gallon just half it ie 4ml instead of 8 and 8ml instead of 16 as you are working at half the ec but I assure you you will want it stronger, mine are at 2.1 EC and it drops every day, I also add 1 tsp of epsoms to my res as I'm finding the lucas formula to be slightly mg light.
What sort of system are you using if yours runs at 2.1 EC (nft, run to waste, soil, etc), Are you growing sea of green style like me ?. As before i switched to vertical growing with sea of green i was using nft tanks with plants i grew to 3-4 feet high & had them on 1200 - 1600 ppm at that time. But that would just be too strong to use on my current setup as the plants are so small that they just don't need as much food
QUOTE
i have a similar system to you and try to run with an EC of around 1.6 (corrected). i did an experimental grow where the EC got to 2.5 before the plants started to suffer but find that they will take all sorts of nutrient abuse before they complain.
mine's vertical with perlite. the plants are 8 to 12 inches and i run to waste. the perlite has been in there for four years now!
QUOTE
the plants are so small that they just don't need as much food
it's not a matter of how much they need, it's a matter of how much they'll take before they burn. any extra will just not be used.
What vertical grow system are you using, please?
cheers
vangraffe
cheers
vangraffe
QUOTE(vangraffe @ Oct 11 2008, 05:58 PM)
What vertical grow system are you using, please?
cheers
vangraffe
cheers
vangraffe
I'm using a kweek ketel
small coliseum
e2a i like the look of the kweek ketel. cheaper than the coli too.
e2a i like the look of the kweek ketel. cheaper than the coli too.
QUOTE(adsldave @ Oct 11 2008, 05:21 PM)
What sort of system are you using if yours runs at 2.1 EC (nft, run to waste, soil, etc), Are you growing sea of green style like me ?. As before i switched to vertical growing with sea of green i was using nft tanks with plants i grew to 3-4 feet high & had them on 1200 - 1600 ppm at that time. But that would just be too strong to use on my current setup as the plants are so small that they just don't need as much food
Flood and drain mate in an IWS, I understand that your plants may take less feed but I don't think they will.
adsldave, I've been using ro water and the lucas formula for years, no other additives or suppliments but recently I've gone to using Liquid Silicon instead of pH up, looking good so far. I'm no guru but here's my experiences with it.
btw, it's 0/5/10 for young clones.
In separate bubblers, 16L litres res, the pH was a twat to control, to the extent I stopped trying set the pH for the new res and top up with ro only, didn't even measure, change res every 2 weeks. They still grew well despite the manky looking leaves and the yields were good. I liked the reduction in height and them only stretching to double at 12/12 so I stuck with it. Wasn't just the lucas, I also got wild pH swings with Canna although I found Ionic to be the most pH stable, best as in least worst. Bubblers are not quite as good as they're cracked out to be but at least the plants in them are almost impossible to kill.
I once tried a tubbler grow, huge res of 700L, ro water with auto top off float valve and the lucas formula. Worked like a dream. Once a week measure the ec and add enough 1/2 micro/bloom to bring it back up to target. pH never once went out of range. Entire grow without a res change, just as well because the res took almost a week to fill.
I tried passive hydro last year, hempy buckets for the first go. Made the mistake of having the ec and pH too low, everyone elses hempy buckets were lush green and mine looked like my bubbler grows. Hiked it up nearer full strength, ec 1.7, pH of 6.1/6.2 and all was well. 2nd grow was my first ever ♫All the leaves are green♫
It's in my nature to keep trying things, hempy buckets and 11L square pots, Fytocell as a medium, let's try an air pot etc. but the passive hydro, ro water and the lucas formula is going to be a forever constant in my growing life. All that faffing about I used to do reading pH then trying to guess how much adjuster to put in, oh shit I've used too much...it's now 2 minutes to mix the nutes, 8 minutes to slop the nutes into the buckets, where's that spliff...I've earned it.
If you are planning on recirculating nutes, the res size is important. Get it big enough to go 2 weeks (auto top up) before the ec and pH goes out of range, then do addback every week, bye bye to res changes.
btw, it's 0/5/10 for young clones.
In separate bubblers, 16L litres res, the pH was a twat to control, to the extent I stopped trying set the pH for the new res and top up with ro only, didn't even measure, change res every 2 weeks. They still grew well despite the manky looking leaves and the yields were good. I liked the reduction in height and them only stretching to double at 12/12 so I stuck with it. Wasn't just the lucas, I also got wild pH swings with Canna although I found Ionic to be the most pH stable, best as in least worst. Bubblers are not quite as good as they're cracked out to be but at least the plants in them are almost impossible to kill.
I once tried a tubbler grow, huge res of 700L, ro water with auto top off float valve and the lucas formula. Worked like a dream. Once a week measure the ec and add enough 1/2 micro/bloom to bring it back up to target. pH never once went out of range. Entire grow without a res change, just as well because the res took almost a week to fill.
I tried passive hydro last year, hempy buckets for the first go. Made the mistake of having the ec and pH too low, everyone elses hempy buckets were lush green and mine looked like my bubbler grows. Hiked it up nearer full strength, ec 1.7, pH of 6.1/6.2 and all was well. 2nd grow was my first ever ♫All the leaves are green♫
It's in my nature to keep trying things, hempy buckets and 11L square pots, Fytocell as a medium, let's try an air pot etc. but the passive hydro, ro water and the lucas formula is going to be a forever constant in my growing life. All that faffing about I used to do reading pH then trying to guess how much adjuster to put in, oh shit I've used too much...it's now 2 minutes to mix the nutes, 8 minutes to slop the nutes into the buckets, where's that spliff...I've earned it.
If you are planning on recirculating nutes, the res size is important. Get it big enough to go 2 weeks (auto top up) before the ec and pH goes out of range, then do addback every week, bye bye to res changes.
QUOTE(lazi @ Oct 11 2008, 07:55 PM)
adsldave, I've been using ro water and the lucas formula for years, no other additives or suppliments but recently I've gone to using Liquid Silicon instead of pH up, looking good so far. I'm no guru but here's my experiences with it.
btw, it's 0/5/10 for young clones.
In separate bubblers, 16L litres res, the pH was a twat to control, to the extent I stopped trying set the pH for the new res and top up with ro only, didn't even measure, change res every 2 weeks. They still grew well despite the manky looking leaves and the yields were good. I liked the reduction in height and them only stretching to double at 12/12 so I stuck with it. Wasn't just the lucas, I also got wild pH swings with Canna although I found Ionic to be the most pH stable, best as in least worst. Bubblers are not quite as good as they're cracked out to be but at least the plants in them are almost impossible to kill.
I once tried a tubbler grow, huge res of 700L, ro water with auto top off float valve and the lucas formula. Worked like a dream. Once a week measure the ec and add enough 1/2 micro/bloom to bring it back up to target. pH never once went out of range. Entire grow without a res change, just as well because the res took almost a week to fill.
I tried passive hydro last year, hempy buckets for the first go. Made the mistake of having the ec and pH too low, everyone elses hempy buckets were lush green and mine looked like my bubbler grows. Hiked it up nearer full strength, ec 1.7, pH of 6.1/6.2 and all was well. 2nd grow was my first ever ♫All the leaves are green♫
It's in my nature to keep trying things, hempy buckets and 11L square pots, Fytocell as a medium, let's try an air pot etc. but the passive hydro, ro water and the lucas formula is going to be a forever constant in my growing life. All that faffing about I used to do reading pH then trying to guess how much adjuster to put in, oh shit I've used too much...it's now 2 minutes to mix the nutes, 8 minutes to slop the nutes into the buckets, where's that spliff...I've earned it.
If you are planning on recirculating nutes, the res size is important. Get it big enough to go 2 weeks (auto top up) before the ec and pH goes out of range, then do addback every week, bye bye to res changes.
btw, it's 0/5/10 for young clones.
In separate bubblers, 16L litres res, the pH was a twat to control, to the extent I stopped trying set the pH for the new res and top up with ro only, didn't even measure, change res every 2 weeks. They still grew well despite the manky looking leaves and the yields were good. I liked the reduction in height and them only stretching to double at 12/12 so I stuck with it. Wasn't just the lucas, I also got wild pH swings with Canna although I found Ionic to be the most pH stable, best as in least worst. Bubblers are not quite as good as they're cracked out to be but at least the plants in them are almost impossible to kill.
I once tried a tubbler grow, huge res of 700L, ro water with auto top off float valve and the lucas formula. Worked like a dream. Once a week measure the ec and add enough 1/2 micro/bloom to bring it back up to target. pH never once went out of range. Entire grow without a res change, just as well because the res took almost a week to fill.
I tried passive hydro last year, hempy buckets for the first go. Made the mistake of having the ec and pH too low, everyone elses hempy buckets were lush green and mine looked like my bubbler grows. Hiked it up nearer full strength, ec 1.7, pH of 6.1/6.2 and all was well. 2nd grow was my first ever ♫All the leaves are green♫
It's in my nature to keep trying things, hempy buckets and 11L square pots, Fytocell as a medium, let's try an air pot etc. but the passive hydro, ro water and the lucas formula is going to be a forever constant in my growing life. All that faffing about I used to do reading pH then trying to guess how much adjuster to put in, oh shit I've used too much...it's now 2 minutes to mix the nutes, 8 minutes to slop the nutes into the buckets, where's that spliff...I've earned it.
If you are planning on recirculating nutes, the res size is important. Get it big enough to go 2 weeks (auto top up) before the ec and pH goes out of range, then do addback every week, bye bye to res changes.
Personally i've grown in soil for a few years (indoors) & then spent 5-6 years growing in nft tanks, Went to vertical growing approx 18 months ago & liked the quick results (7 to 7 & half weeks from the day the clones go in to cropping).
I have about 90 litres in my res when full & the plants use between 10-15 litres a day (when their 10 or more days into flowering that is), I have 2 vertical systems going at the same time so i crop once a month on average.
I can't have a bigger res than i already have for each system. I just add a bucket of fresh nutrients everyday (bucket is aprrox 13-14 litres).
I suppose i will just have to go for a trial & error approach to see what the ph changes are like with my canna aqua in one system & get some general hydro stuff to make some lucas formula for my other system so i can compare results.
Do i need to add anything else to either nutrient mixture ? (eg epsom salts), Or will the nutrient mixture with ro water have a plentiful supply of all the essential nutrients & micro nutrients ?
When i mixed up a bucket of mixture today with ro water it was ph 5.6, So if i filled up my entire res with that nutrient mixture would it stay at 5.6 or at least close to it ?. Or would it change dramiticly ?, If it would change dramaticly could someone with expereince on this kind of situation give a rough idea of the sort of ph changes that would occur.
QUOTE(adsldave @ Oct 11 2008, 08:45 PM)
When i mixed up a bucket of mixture today with ro water it was ph 5.6, So if i filled up my entire res with that nutrient mixture would it stay at 5.6 or at least close to it ?. Or would it change dramiticly ?, If it would change dramaticly could someone with expereince on this kind of situation give a rough idea of the sort of ph changes that would occur.
5.6 is good to start at, I have found the lucas formula starts about EC 1.9 ish and drops while pH goes up, I'm at the stage in growth where I'm adding 20ml micro and 40ml bloom every 2 days to bring it to a stage where it will slow my nute uptake and the pH stabelish.
I have found that a teaspoon of epsoms to every 25 litres of reservoir helps as well.
QUOTE(snadge @ Oct 11 2008, 09:30 PM)
QUOTE(adsldave @ Oct 11 2008, 08:45 PM)
When i mixed up a bucket of mixture today with ro water it was ph 5.6, So if i filled up my entire res with that nutrient mixture would it stay at 5.6 or at least close to it ?. Or would it change dramiticly ?, If it would change dramaticly could someone with expereince on this kind of situation give a rough idea of the sort of ph changes that would occur.
5.6 is good to start at, I have found the lucas formula starts about EC 1.9 ish and drops while pH goes up, I'm at the stage in growth where I'm adding 20ml micro and 40ml bloom every 2 days to bring it to a stage where it will slow my nute uptake and the pH stabelish.
I have found that a teaspoon of epsoms to every 25 litres of reservoir helps as well.
Is lucas formula abit low in magnesium then if your using epsom salts ?. What is the ph like when you first start a crop (i presume you have lower strength nutrient mixture for the first week or so while the cuttings are starting to grow) ?
Just made up a bucket of fresh nutrients & i added 15ml of part a & 15ml of part b (canna aqua). The ph of my ro water before i added the nutrients was 6.2 but after i added the nutrients the ph dropped to 4.4, This is what i'm trying to avoid.
Obviously i can't really fill up my res with nutrients at this ph level as it's way too low, I would prefer to not add any ph up aswell.
10 mins later i added approx 30-35 ml of canna terra vega to a fresh bucket of ro water for my mother plants, again the ph dropped down to approx ph 4.2. So i just added approx 3 litres of tap water & the ph went back up to ph 6.2 which i presume is because it has buffered the ro water.
Now does the lucas formula buffer the ro water so that the ph is in the 5.6 to 6.0 range ?, Probably more important for me is does the lucas formula buffer the ro water if i use a weaker solution so i get an ec of 1.0 to 1.2 ?
Obviously i can't really fill up my res with nutrients at this ph level as it's way too low, I would prefer to not add any ph up aswell.
10 mins later i added approx 30-35 ml of canna terra vega to a fresh bucket of ro water for my mother plants, again the ph dropped down to approx ph 4.2. So i just added approx 3 litres of tap water & the ph went back up to ph 6.2 which i presume is because it has buffered the ro water.
Now does the lucas formula buffer the ro water so that the ph is in the 5.6 to 6.0 range ?, Probably more important for me is does the lucas formula buffer the ro water if i use a weaker solution so i get an ec of 1.0 to 1.2 ?
The lucas formula uses GH flora micro and bloom, not canna.
Also under fluoros he suggests using 2/3rds strength but under HIDs use full strength REGARDLESS of size of plant.
so you should use full strength.
I used full strength on plants 2 days from rooted clone under MH and they were spot on.
Also under fluoros he suggests using 2/3rds strength but under HIDs use full strength REGARDLESS of size of plant.
so you should use full strength.
I used full strength on plants 2 days from rooted clone under MH and they were spot on.
QUOTE(snadge @ Oct 12 2008, 11:47 AM)
The lucas formula uses GH flora micro and bloom, not canna.
Also under fluoros he suggests using 2/3rds strength but under HIDs use full strength REGARDLESS of size of plant.
so you should use full strength.
I used full strength on plants 2 days from rooted clone under MH and they were spot on.
Also under fluoros he suggests using 2/3rds strength but under HIDs use full strength REGARDLESS of size of plant.
so you should use full strength.
I used full strength on plants 2 days from rooted clone under MH and they were spot on.
Yeah i know the lucas formula uses general hydroponics & not canna, But i haven't got any general hydroponics at the moment & i don't want to buy some if it's not going to work for me which is why i'm in here asking questions.
Personally i've always used a lower strength nutrient solution to begin with & increased the strength over approx 10-14 days, I've tried using full strength solution from the beginning before (with canna that is). But i've always found that if i had a solution of say 1.4, Then the next day or maybe the day after that the solution would jump from 1.4 to 1.5 or 1.6 & keep jumping up. Which over the course of the crop would cause various nutrient problems (burn, deficiencies, etc) & also affected my ph levels more.
So this doesn't happen if i use the lucas formula then ?
well I haven't had any problems like that, I started a tad low @ 1.9 Ec and found my Ec dropped and my pH went up, I raised my Ec to 2.1 now and both seem a lot more stable.
Although some plants are happy on the plain lucas formula my snowdogs were looking pale so I added a couple of teaspoons of epsoms (dissolved in hot water) to my res and they look a lot better.
I don't know how you would mix canna nutes to get the NPK,Mg ratios of lucas formula as all are different.
QUOTE(snadge @ Oct 12 2008, 12:28 PM)
well I haven't had any problems like that, I started a tad low @ 1.9 Ec and found my Ec dropped and my pH went up, I raised my Ec to 2.1 now and both seem a lot more stable.
Although some plants are happy on the plain lucas formula my snowdogs were looking pale so I added a couple of teaspoons of epsoms (dissolved in hot water) to my res and they look a lot better.
I don't know how you would mix canna nutes to get the NPK,Mg ratios of lucas formula as all are different.
Although some plants are happy on the plain lucas formula my snowdogs were looking pale so I added a couple of teaspoons of epsoms (dissolved in hot water) to my res and they look a lot better.
I don't know how you would mix canna nutes to get the NPK,Mg ratios of lucas formula as all are different.
so whats your ph at when using the lucas formula with ro water (ph before added to res & ph of res after being added & circulated) ?
my pH of RO is around 6.8
when my nutes are added it is about 5.6/5.7 and EC of about 1.95.
after a day my pH will have risen and my EC dropped so I will add micro/bloom at a ratio of 1:2 until my EC is at 2.1 my pH will be at around 5.7, I add enough Nitric acid pH down to get to 5.55/5.6 then leave it for a week it will be at pH 6.1/6.2 and EC 1.8, I then addback RO and nutes in 1:2 ratio once again to get EC to 2.1 and add pH down to lower to 5.55 ish.
you need to take notes until you can dial the strain in, there is still a little fiddling around to do even with such a low maintenance regime, one size does not fit all.
QUOTE(snadge @ Oct 12 2008, 01:31 PM)
my pH of RO is around 6.8
when my nutes are added it is about 5.6/5.7 and EC of about 1.95.
after a day my pH will have risen and my EC dropped so I will add micro/bloom at a ratio of 1:2 until my EC is at 2.1 my pH will be at around 5.7, I add enough Nitric acid pH down to get to 5.55/5.6 then leave it for a week it will be at pH 6.1/6.2 and EC 1.8, I then addback RO and nutes in 1:2 ratio once again to get EC to 2.1 and add pH down to lower to 5.55 ish.
you need to take notes until you can dial the strain in, there is still a little fiddling around to do even with such a low maintenance regime, one size does not fit all.
when my nutes are added it is about 5.6/5.7 and EC of about 1.95.
after a day my pH will have risen and my EC dropped so I will add micro/bloom at a ratio of 1:2 until my EC is at 2.1 my pH will be at around 5.7, I add enough Nitric acid pH down to get to 5.55/5.6 then leave it for a week it will be at pH 6.1/6.2 and EC 1.8, I then addback RO and nutes in 1:2 ratio once again to get EC to 2.1 and add pH down to lower to 5.55 ish.
you need to take notes until you can dial the strain in, there is still a little fiddling around to do even with such a low maintenance regime, one size does not fit all.
The ph of my ro water is 6.2 so at a guess my nutrient solution (when i get some general hydroponics nutrients) will be at around 5.0 - 5.2 (based on the fact that your nutrient solution drops approx 1.0 in ph levels). I would probably have to add a small amount of ph up or a small amount of tap water to get it up to 5.6.
Going to have to try & find a local shop that sells general hydroponics as i would prefer to not order this stuff from an online retailer as they would have my details.
Here is the link to the site of the guy who started it all,"pH", Lucas would be the first to tell so.
http://www.angelfire.com/cantina/fourtwenty/index.html
http://www.angelfire.com/cantina/fourtwenty/index.html
QUOTE(Wm. Duffy @ Oct 12 2008, 07:51 PM)
Here is the link to the site of the guy who started it all,"pH", Lucas would be the first to tell so.
http://www.angelfire.com/cantina/fourtwenty/index.html
http://www.angelfire.com/cantina/fourtwenty/index.html
Thanks alot for the link that was quite informative & i will be starting a control track of my own in a few weeks when i start my next crop, I think i will do a control track for both canna & general hydroponics to see what sort of results & differences i get.
My only slight problem is that i grow 2 different strain at the same time in my system (50% of one strain & 50% of the other strain), Which will no doubt result in more ph & ec changes than if i had just one strain growing (but worth the effort).
Again thanks for that link that was a great read
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