Lucas Formula

[anongreen]

So, I'm sure everyone knows about the Lucas formula.

G-M-B (Grow-Micro-Bloom)
0-5-10 - For Vegetative cycle (24/0)
0-8-16 - For Flowering cycle (12/12)

Now, I have purchased Grow, Micro, and Bloom. Is there any use for Grow at all? I'm pretty new to hydro growing, but to me it would make sense to use grow. I've been looking for different nutrient soup opinions, but it looks like the Lucas Formula has a monopoly on it! I'm wondering if anyone has any evidence that using Grow is bad or good. If it's bad, I guess it will have a nice place sitting in my basement doing nothing, heh.

[mordgrow]

if you read the lucas formula, you'll see that there is a zero under grow, that means no use whatso ever

here is a more detailed discription of the lucas formula

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.

http://www.drugs-forum.com/growfaq/1654.htm

enjoy

(and take that GH Grow back for a refund :P)

[anongreen]

Yeah, I know there's a zero, but I was wondering if any other method utilizes grow? I was just curious if Grow has a purpose in any other nutrient recipe, and why it doesn't in the Lucas formula. Thanks for the link, though, I guess I'll go with the Lucas Formula.

[mordgrow]

Lucas formula is by far the "safest" route, start with that, when you've got everything else under conrol, you can start playing with nutes (if you want) for better plants.


the GH system is designed as a 3 part system, the "Grow" has a high N content, but Micro has enough N in it to cover vegitation.

you should be very happy with the lucas formula.

[stilalive2029]

http://www.drugs-forum.com/growfaq/G...c%20Topics.htm

a quarter of the way down it says What are the best ratios for General Hydroponics 3-part?...there are some recipes for you

[ocitown]

Originally Posted by stilalive2029

http://www.drugs-forum.com/growfaq/G...c%20Topics.htm

a quarter of the way down it says What are the best ratios for General Hydroponics 3-part?...there are some recipes for you

Great site man,+rep

[Adult_Toke]

The only problem I've had with the Lucas Formula so far is my plants started to suffer from magnesium deficiencies for some reason. I'd keep some epsom salts on hand just in case they start showing signs.

Also, I was never able to get a definitive answer on what PPM levels are appropriate for the Lucas Formula. What are these " TDS @ 0.5 conversion" and "TDS @ 0.7 conversion" all about? Why need to convert to anything when it shows just what PPM my reservoir is right on my TDS meter? Right now my reservoir is at 1000-1200 ppm according to my meter.

[ocitown]

Originally Posted by Adult_Toke

The only problem I've had with the Lucas Formula so far is my plants started to suffer from magnesium deficiencies for some reason. I'd keep some epsom salts on hand just in case they start showing signs.

Also, I was never able to get a definitive answer on what PPM levels are appropriate for the Lucas Formula. What are these " TDS @ 0.5 conversion" and "TDS @ 0.7 conversion" all about? Why need to convert to anything when it shows just what PPM my reservoir is right on my TDS meter? Right now my reservoir is at 1000-1200 ppm according to my meter.

The GH micro should cover the mag when using R/O and PPM is a conversion from EC which is converted to PPM using either x500 or x700.

You should find out which conversion factor YOUR meter uses so you can use the correct measures,using a real time and another dip type both using dif. factors will confuse the daylights out of you if your not aware of this vairiance.

[VeoDigital]

Whats the reasons for them using two different conversions of .5 or .7? Why cant they just make it a uniform conversion factor? BTW does anyone else really calibrate their ph pens or tds pens weekly like recommended? I have been and this milwaukee sucks.

[up4anything]

Originally Posted by VeoDigital

Whats the reasons for them using two different conversions of .5 or .7? Why cant they just make it a uniform conversion factor? BTW does anyone else really calibrate their ph pens or tds pens weekly like recommended? I have been and this milwaukee sucks.

What milwaukee do you have? I've used Milwukee for a long time with no complaints at all. Is it still under warranty? Do you maintain the probes?

[VeoDigital]

The pH600, its yellow and of the pen variety. I calibrate it weekly, but tests back to back yield a large margin of error, sometimes a full .5+/-

idk if its still under warranty, and I do keep the probe very clean

Thinking about getting a hanna 3 in 1

[ocitown]

Originally Posted by VeoDigital

The pH600, its yellow and of the pen variety. I calibrate it weekly, but tests back to back yield a large margin of error, sometimes a full .5+/-

idk if its still under warranty, and I do keep the probe very clean

Thinking about getting a hanna 3 in 1

I have a hana on-line 2 in 1 w/dosing alarm( the light blue one) and love it,it stays within .1 every 2 weeks but wish i now got the 3 in 1. Soon when i get a cooler it wont matter since the cooler displays digital temps.

[Help_Needed]

One note on the Lucas Formula...which will probably also deal with the poster who is reporting the Mg deficiencies.

Lucas has made a minor revision to his Formula since the version that was posted was written up (you can find it buried deep in his Ask Lucas thread on another forum). He no longer recommends having the different strenght for veg and flowering. Now he recommends that your lighting determine what strength you use. If you're growing under flouro's use the 0-5-10 ratio. If you're growing under HID, use the 0-8-16.

[Adult_Toke]

So basically there is only one formula for veg and flowering if you're someone using CFLs like myself? Guess that makes things simpler.

[ocitown]

Originally Posted by Adult_Toke

So basically there is only one formula for veg and flowering if you're someone using CFLs like myself? Guess that makes things simpler.

Theres only one formula, that formulation only varies if you change from CFLs to HIDs.

My veg. CFLs get 0-5-10 and my flowering HIDs get the 0-8-16.