Molasses in nute water

Can anyone share if molasses is worth a look to add into nute water? What are the benefits?

I’ve read about using molasses, but don’t know much about the reasons it is suggested. Thanks!

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I use it in the last few waterings before harvest but I Don’t mix with Nute water. Not sure if others do


I run molasses with or without nutes. Obviously the water gets thicker but stick to 1tbsp or less n it works good. I run in veg and fliwer. Once ive stacked microbes up.

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I add 1Tbs of unsulfured molassas per gallon once a week starting last week of veg and ending week six of flower.
It’s supposed to give food to the microbes in the soil that breakdown the nutrients the plant eats.
Adding it with nutrients or without shouldn’t make any difference.


Besides the microbial benefit in the soil, is there any terpene advantage to molasses that may enhance the taste?

If it’s hydro I would recommend against use of any sugars in the nutes. Breed bacterial blooms.


Just FF OF with xtra Perlite. Soil based medium.

I think @MattyBear uses molasses in his waterings?


Hope @MattyBear will see this and weight in. I’m using Advanced Nutrients base nutes and bud enhancers so I don’t want to add molasses unless I do some research.

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Exactly right. The molasses does nothing directly for the plant but is (in theory!) beneficial to the micro flora present in soil and media. And as @WickedAle said; not in hydro.


Makes perfect sense in that hydro doesn’t need to be broken down like soil. Good info!!

Question: I’m preparing to shift from Ocean Forest to Pro Mix HP on my next indoor grow. In a “soilless” medium like Pro-Mix, would molasses be of benefit since there is probably not much to break down like in Ocean Forest?


I use Promix HP and prefer it over all other mediums. It’s inoculated with mycorrhizai and there are supplemental microbes (Azos and Mykos) that you can introduce. I typically don’t use molasses because I never saw any benefit over just running commercial nutrients.

A couple of caveats with this medium: nominal PH is around 6.0 to 6.1 IMO, borne out by others who agree. You don’t have the salt buildup like in coco. Cal mag is not necessarily called for (unlike coco which sequesters calcium and magnesium). Promix is NOT a renewable resource if that interests you unlike coco which is.

Both will show accelerated growth over soil based on my experience. Cannabis likes dry loose airy soil.


I use Molasses with Epsom salts on non feed days, and then at the end of flower for the last week or so. The buds love the extra sulfur from the Epsom salts and the molasses helps feed microbial activity without being too harsh on the ppms towards the end.


I really appreciate your input @Myfriendis410. I have had great results with OF, but the low ph swings in this medium really concern me to the point of shifting. Seems OF has a mind of it own, and it doesn’t give a darn what you try to make the ph.

I’m using Advanced Nutrients Ph Perfect base nutes, so I’ll stick with those in the Pro Mix when I start. I bought a 3.8 cf foot bale of P-M last week and the shop owner say this is the best choice he made to start using P-M.


What grow medium do you use @MattyBear?

Promix HP or coco are my favorite mediums because of the total control I have over what the plants eat.


Yes, for sure that loss of control is what is moving me out of FF OF and into the loving arms of Pro-Mix…lol. I realize I’ll need to feed the seedling plants after the cotyledons have done their thing, but I’ll be so ready to not fret over crazy low ph in OF any longer.

Thanks for the molasses tip and feed schedule.

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Likely this is the result of a large root ball in soil supporting a canopy a bit too large for the roots. Organic material dies off, salts are exchanged and this drives the PH down; usually in late flower. Dolomite lime added as a top dressing can help and a larger pot for plant size can help greatly. You can run into the same issues with soilless media.


You’re a good resource! I actually did top dress the medium with a couple of tablespoons of DL and it seems to have buffered the acidity.

When I get into Pro Mix, I’ll ask for some pointers if you don’t mind. I’m using Advanced Nutes with Ph Perfect chelation.

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Some great info here everyone, thanks. I too have started to experiment with the molasses in an organic soil that I utilize a 30% PM and 30% Perlite/Vermiculite (60/40 ratio) to help keep soil loose and aerated. Ive seen a marked improvement with the added benefits of feeding the microbes that the organic soil provides allowing the plants a seemingly easier time absorbing nutes. Adjusting to indoor growing is a bit of work, first grow had me working non stop with excesses and deficiencies, and the insane battle of determining which was which and how to fix it. I would have had a better time w a smaller grow, started with 32 seeds germinated, and after culling males and couple seedling deaths, harvested 23 females. Yes, It was bag seed, from a couple “friends”, bought from ILGM from there on.
My question - Im planning on switching from 5 gal buckets to 5 gal fabric pots. Does anyone have experience with them and is there an issue with mold or mildew to be concerned about? The molasses is a question in particular, will it provide the perfect breeding grounds for trouble? The soil is very rich and loamy, im worried it may cause or at the least perpetuate these issues by making the switch and keeping the microbe colonies thriving and well fed with molasses.

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