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The Ask Lucas Knowledge Base

The Ask Lucas Knowledge Base is a collection of ideas, opinions and teachings of Lucas, of "Lucas Formula" fame, as gleaned from the Ask Lucas thread found at Cannabis-World. Lucas gave generously of his knowledge regarding indoor hydroponic gardening, only asking that those he helped do the same by sharing what they learn with others. This is my attempt at giving back; I am not Lucas.

Some Details...

There is a lot of misinformation floating around the Internet regarding Lucas and the Lucas Formula. While Lucas is often credited with developing the Lucas Forumla, he quickly points to his own teacher from CannaStats. Says Lucas of CannaStats, "I am a student of the owner of that page (his handle is "pH") and have shared what I learned from there. The Lucas Formula was not my idea, I learned it from pH."

pH's spreadsheet ( is used to calculate the Lucas Formula with any premix nutrient line for which you have a guaranteed analysis. It is referenced throughout the Ask Lucas thread and may also be downloaded from CannaStats/Downloads. Typically, however, when one speaks of The Lucas Formula, it is in reference to the 3 part General Hydroponics Flora Series line, of which only the Micro and Bloom components are used (8ml and 16ml per gallon of Reverse Osmosis water, respectively).

Knowledge Base Usage & Navigation

The majority of Lucas' ideas and opinions have been copied and pasted verbatim from the original thread. Minor syntax corrections have occasionally been made for the sake of easy reading. User questions are denoted with ">", and Lucas' responses follow.

Ask Lucas Comes to a Close:

I want to humbly thank everyone here for asking my opinion on anything.

And I want to highlight that it was my mentor pH who originally did the research on yield that resulted in the 0-8-16 recipe. fwiw, nutes do not affect yield, they affect health. Any nutes that produce health, produce yield. There is no magic ingredient that will change your plants from schwag to dank, its the genetics, and the ability to be healthy and achieve their potential, that makes plants phat.

The only "secret" I think I know, is that the magic is in the "air". That means both oxygen for roots and co2 for canopy. And fwiw, at the moment, there is a strong trend to use hand watered medium with great success. There is nothing about hydro that promises more yield, just more free time. Its basically a way to automate watering. The current favorite hydro system I like is the Multifarm. I prefer 600w HPS to any other option, and I lean heavily towards sealed rooms with CO2 and Air Conditioning.. For veg I like 2x4 ebb flow lit by 400w T5 arrays. I still like to clone with a dome and a heating mat in rockwool cubes in a nursery flat.

... Thanks to the newsgroup alt.cannabis.cultivation, Weedbase, Overgrow, Heavens Stairway, CannabisWorld,, Mr. Soul, ceteris paribus, raydavies, newbie,, Aeric77, General Hydroponics, Hydrofarm, highgrade, emsmess, and many many more from then and now

It is an honor to be trusted among the chain of torchbearers.

I will still look forward to participating with you in sharing the joy, and can be reached by PM.

And I encourage everyone here to act in ways that help the plant Cannabis, to continue to serve humankind, by sharing live cuttings of important clones whenever possible.

I also want to applaud all the new people coming to learn how to be part of this family of farmers that have been with us since the beginning of time. Pass it on.

Peace in our lifetime

"It's ok, some of my best friends are newbies.. and I coach them to pay back the people who coached me when I was a newbie.. in fact, Im still a newbie, and still learn new things from others.

Your mission, is to learn, and then teach others."


The Lucas Formula

The Lucas Formula recommends General Hydroponics Flora Seris Micro (8ml/gal) and Bloom (16ml/gal) in reverse osmosis water, under HID lighting. The TDS levels acheived with this GH recipe has known NPK and Mg levels that approximate the Mel Frank guidelines found at CannaStats.

Lucas Formula: Addback

It is not necessary to dump your reservoir with the correct addback strategy. Using a little simple math and his trusty TDS/EC monitor, the gardener can greatly reduce the waste involved in pouring nutrients down the drain.

Hydroponics: Getting Started

With a little prior planning the prospective gardener will save himself time and money by appropriately sizing all aspects of the indoor garden.

Lucas on...



Special Thanks To

Unique Information for the Advanced Indoor Cannabis Cultivator