Lucas formula

Has anyone ever tried the Lucas Formula in Coco using General Hydroponics Flora Series?


It’s all I use

I’ve used it so long that I’ve learned to make varying ratios other than just the 1:2 that it is the norm to fit different stages of growth


Thanks that’s the article I had read.

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For me GH is the most reliable company , has been in the market for a very long time , with acceptable prices .
I have never used Lucas formula ,but i have read about it and it looks similar to GH Maxi Schedule , where you have two parts in powder form ,is more economic (5 times cheaper ) and work same as GH Flora which is 3 part schedule and gives you a little bit more freedom to play with the schedule .


How do you dilute it to get it at the right EC and ppm for each stage?

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I used it for several grows from start to finish. When using it I did augment with a couple of supplemental items in coco. I typically hold onto moms in coco/perlite.

The way I go about setting the PPM I want is simple - I mix a 5 gallon bucket at full strength Lucas Formula and then use a siphon pump to pump half of it into another bucket, then add water to the bucket while holding my PPM meter in it until the PPMs get where I want them - basically, just water it down to where you want it. This is an easy way to get exactly the PPMs you want.

But once you use the schedule for awhile, you will know how much of each you really need for specific PPMs, and will be able to must mix, for example, 2ml of Micro and 4ml of Bloom for, say, an early veg feeding level.

For a coco grow using Lucas, you probably need to add in some calmag and silica. This is my standard full strength feeding schedule using Lucas (per gallon of water):

Micro - 8ml
Bloom - 16ml
Calimagic - 2-5ml
Armor Si - 2-5ml depending on plant phase

In flower I typically added Liquid Koolbloom once through transition for 2-3 weeks, then I switch to Dry Koolbloom in mid-flower. The amount I add is based on where I want my PPMs.

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You put the 8ml of micro in per gallon, so if you have 8 gallons you will need 64ml of micro

You do the bloom the same way except with 16ml of bloom per gallon

I use ppms in place of EC. In my experience a full strength Lucas mixture will only come out to about 800ppms. Many people want a higher fertilizer concentration than that inn late flower and so I have done the Lucas long enough that I have been able to develop my own ratios for what I like in different stages of growth

I would suggest doing an entire grow with just the 8ml micro and 16km of bloom per gallon. Contrary to popular belief, a plant will still grow well with only 800ppms of fertilizer, even in late stages.

You might not get massive buds but you would have a healthy and happy plant that will produce well.

After you do one grow then you can make adjustments where you see necessary.

I do almost straight Lucas in the veg stage. Once flower arrives I will still do straight Lucas but begin to add “bloom boosters” to increase my P and K

@Bogleg has a good handle on it too


Same. Since I grow hydro and use Rapid Rooters to start germinated seeds, I also provide nutrients to my plants from day 1. I soak my Rapid Rooters in a mild nutrient solution (200-250ppm) made up of just the base Lucas Formula (Micro and Bloom).

Once I place the germinated seeds in them and they emerge from the rooters, then I just mist them with properly PH’d plain water (no nutrients) until they are established in the Rapid Rooters. Usually, to keep the Rapid Rooters slightly damp, this requires misting them a couple of times per day, for me.

Once they can be transplanted over a bucket or bubble cloner to keep growing and expanding their roots, I raise up my PPMs to around 400, and then once they are solidly established into the vegetative state, I will, like @tdubwilly, increase my PPMs each week, culminating in reaching the full Lucas Formula strength at the time I make the flip to 12/12.