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Message added by Zoot

It has come to my attention that Fox Farm makes a product called Gringo Rasta.

It has the same numbers and is made up with the same stuff as General Hydroponics.
















Side by side comparison





So, it would appear to be a safe swap from GH to Fox Farm using the same measurements.

Lucas Formula - A Hydro/Soil/Coco Feeding Strategy



Lucas Formula - A Hydro/Soil/Coco Feeding Strategy



Lucas Formula, sometimes known as the Lucas Ratio, is less complicated than it initially seems. It is nothing more than a basic recipe of nutrients to give your plants during both the vegetative, and the flowering state.


The original recipe uses 2 parts of the General Hydroponics 3-part FLORA series (Gro, Micro, Bloom) nutrient system, but Lucas Formula may also be used with Advanced Nutrients, GH's dry nutes (Maxibloom), etc.


Lucas Formula using General Hydroponics 3-Part System


General Hydroponics makes a 3-part system named the FLORA series. It consists of FLORA GROW, FLORA MICRO, and FLORA BLOOM. These are 3 bottles you buy, that you would normally use together throughout the entire grow. You may use it as per the instructions on the bottle, with excellent results, but...


Lucas figured out that FLORA MICRO contains enough nitrogen, and everything else that MICRO GRO contains, that you use it with FLORA BLOOM alone, saving you from having to buy FLORA GRO.


How do you use it? Simple. Add 8ml of Flora Micro (dark red stuff) to 1 gallon of water*, mix, and then add 16ml of Flora Bloom (pink stuff) into the water, and mix. Done - unless you're growing in coco. If so, see below.'



Lucas Formula using General Hydroponics Dry Nutrients (MaxiBloom)


MaxiBloom and MaxiGro are dry nutrient also from General Hydroponics. It turns out, Maxibloom, used in a ratio of 7 grams per gallon of water*, is very close to the original Lucas Formula (above.) You do not need MaxiGro, and so this is the cheapest and easiest recipe to use.


Add 7 grams of Maxibloom into 1 gallon of water*, and then adjust the pH, and stir vigorously to dissolve the Maxibloom in the water. I advise putting the 7g of Maxibloom into a cup of warm water, dissolving it, and then adding it to the remaining gallon of water, before pH adjusting and mixing again.



Lucas Formula using General Hydroponics FloraNova series


This is probably the easiest (but not cheapest - see MaxiBloom above) feeding plan available. If you're using General Hydroponics' FloraNova Bloom 1-part system, simply add 8ml of FloraNova per gallon of water* and feed.



Lucas Formula when growing in Coco Coir - Head's Formula


If you're growing in coco, you may need to adjust the Lucas formula slightly to compensate for a property of coco which may result in a calcium or magnesium deficiency. How? You may be able to get by simply by adding 1-2ml of calmag (or MagiCal+), or 1 gram of Epsom salt (any pharmacy carries this), per gallon of water, before feeding the plants.


There is a modified formula specifically for Coco that consists of using a different ratio: 6ml of Flora Micro, and 9ml of Flora Bloom, per gallon of water, along with 1 gram of Epsom salt per water.


Either works, but be sure to try Head's Formula if you're having deficiencies or other nute/pH problems.


Low light ratio, and flowering vs veg


Lucas Formula should be used in the same ratio throughout the grow. There is a misconception that one should use 5ml of Micro and 10ml of Bloom, when in veg, and switch to 8ml of Micro, and 16ml of Bloom, when flowering.


This was never stated by Lucas himself. He originally stated that the 0-5-10 ratio was for LOW LIGHT situations (fluorescent lighting like PL/L and CFLs, or HID lamps less than 400W), whereas 0-8-16 is for medium to high light (400W+)


* What type of water should I use? What about pH/ppm?


The original formula uses reverse osmosis, or RO, water, and is intended to be used without having to measure pH and ppm. Reverse Osmosis water makes this possible because it should, in theory, be the same for everyone. It is filtered water, which you can get either by buying a reverse osmosis filter system, or just buying bottled water (among other brands, Dasani, the bottled tap water is reverse osmosis, for example). One may also use dH2O (distilled water) with good results. You can get distilled water from most convenience stores (Walgreens, CSV, Rite-Aide, etc..)



Lucas Formula for seedlings/cuttings


For young plants (< 4 weeks old) or cuttings, which may not be able to handle a full strength feeding formula, may require that you dilute the nutrient solution before feeding. This is OK, just make sure you keep the correct ratio when mixing. For example, 50% strength would be 4ml Micro and 8ml Bloom, or 3.5g of dry Maxibloom per gallon.


Lucas Formula with tap water


You may use Lucas Formula with tap water successfully, but this may require pH adjusting on your part. Keep the pH close to 5.8.



Can I use additives with Lucas Formula?


You may. It is recommended that you do not introduce additives until your setup is dialed in. After you've ironed out any deficiencies and fully understand how your plant and strain likes to be fed, feel free to begin using additives (such as Floralicious) - not that the additives will help. For increased quality and yield, focus on good genetics, and ample light and temperature control, rather than trying to compensate for those with additives.



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Recommended Comments

Guest imiubu


1 hour ago, BillJackson said:

Has anyone sampled the various broker mentioned here, and can they tell which one is the best?


I cannot attest to any of the filters as I don't use one.  Perhaps there is someone who is better versed that will help you out.


Please take a moment to introduce yourself and let us know a bit about you.  Thanks


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I run a modified Lucas formula a lot... I will say you are way better adding gypsum and cal/mg than just Epsom... to much mg will bog out your medium and cause root issues... gypsum is key imo especially in coco as it pushes the salts out... 


great easy system though with a way better final final ratio than the complete 3 parts.., to much potassium!


check out the green planet micro and bloom too.. has added Ca and Epsom.. 

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Guest Morcheeba*


ive ran lucas using 2part, maxi bloom and floranova bloom with success and the floranova bloom produces the best meds.

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Guest Vender


7 hours ago, BillJackson said:

Has anyone sampled the various broker mentioned here, and can they tell which one is the best?


Do a RO under the sink system. GE they cost about $180 at HD. The filters last an extremely long time, over a year or two!  I have well water and change mine every 2-3 years, just because. They are slow at about 2 gallons in 24 hours. I am very happy with mine. Reverse Osmosis is the only way to go. And it makes great drinking water. Those “filter” systems eat cartridges. Jmo

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Guest Vender


I have tried Lucas and was very happy with the results, then I got serious and only use SUCCESS nutrients. It makes a difference. Remember the saying you get what you pay for. 

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I don’t actually agree with that ... most nutrient use the exact same base salts... there are some pretty stupid feed programs out there , but I haven’t seen a night and day difference between most lines, and find if you actually work out the ratios of what you are mixing up you do a lot better regardless of feed... too many bottles of the same thing = shittier results..


chelates in your micronutrients are  the only real difference, but most of the feeds listed have those and if you use things like fulvic acid and enzymes etc they are more effective anyways.


yes there are quality levels in raw salts, and I hate supporting Monsanto/bayer,  but the only real way to achieve this imo is to buy the raw salts yourself from a reputable source, and make your own feed for pennies on the dollar! Otherwise your still buying water / dye / filler /advertising /bottling etc etc..


Customhydronutes is a great source and they have an ig acct with lots of cool stuff.. 

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Tynehead Tom


modified lucas formula for the win

Not everyone can make it work and most folks running true lucas are using the wrong PH and thus getting sub par results and weed that tastes like hay.

Use lucas properly, at the right ratio and PH for your media and the right modifications for the variety being grown and results should be outstanding.

Certainly not a be all end all feeding regime but I think it is one of the better ones for simplicity, cost and results.

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