molasses and compost tea

annafl(z9b/10a Sarasota)July 2, 2006

Recently I read that you should not put molasses in compost tea if the brewing temperature is over 75 degrees. Can anyone tell me why?

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maybe shoulda posted where YOU read that? just a thought hey

    Bookmark   July 2, 2006 at 11:28PM
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Obviously Darkcloud doesn't know the answer and his/her response is reflective of that...

Anna, I don't know the answer either, but do hope that someone chimes in to answer your question in a most respective and intelligent manner.

    Bookmark   July 3, 2006 at 7:57AM
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username_5(banned for no reason)

I don't know the answer, but I think from what I have read it probably has to do with biological activity and oxygen consumption.

Regardless of temperature the more active the bacteria are the more oxygen they consume. In theory then the bacteria can deplete the oxygen faster than it is being introduced.

As temps go up, the bacteria become more active as well so the sugar high they get from molasses might be counter productive. In a sense they end up reducing oxygen and thus their population drops rather than increases.

That's what I have read anyway. Most stuff dealing with *aerated* teas I take with a dump truck full of salt though. You kind of have to because if one listened to all the things about how to make it properly one would conclude it could only be made with specialized, purchased compost and one would need expensive commercial brewers with oxygen meters and an HVAC system to maintain temps in the 'optimal' range of +- 1 degree.

Don't really want any of those wussy bacteria in my garden. I prefer the tough as nails, self sufficient type ;-)

    Bookmark   July 3, 2006 at 9:59AM
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gumby_ct(CT it says Z5)

It may be to feed the bacteria you are trying to grow.

I think what dc was tryin to say is to ask the person who posted it. Make sense to me - we are only guessing here.

    Bookmark   July 3, 2006 at 11:51AM
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hello good humans! molasses promotes the growth of "bad" bacteria in the compost tea. i foliar with molasses straight to boost sugar. there is a ton of stuff on the web concerning do's and don'ts with compost tea. be well

    Bookmark   July 3, 2006 at 12:53PM
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annafl(z9b/10a Sarasota)

Darkcloud, if I remembered where I read that, I would have gone there! Senility rears its ugly head again. I'm not sure it was even on GW. Just don't remember, so I thought you folks might have an idea.

Username 5, that makes good sense. Probably the reasoning behind it. Do you imagine that one could compensate for the molasses driving the bacteria too fast by decreasing the brewing time so as not to use up the oxygen, or is it the rate of oxygen supplied is not as fast as the rapidly growing molasses-fed bacteria are requiring it, providing a deficit no matter what the brewing time? Now you've got me thinking.

Swampfarmer, by "bad" do you mean anaerobic or just a certain type of bacteria that thrives on a sugar solution?

    Bookmark   July 3, 2006 at 4:27PM
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I've read the exact thing... I'll put the link below. Maybe that is where you heard it? Doesn't really matter anyway... experience is the key - which I don't have yet.

Here is a link that might be useful: compost link

    Bookmark   July 3, 2006 at 6:12PM
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annafl , please accept my apology. it was not meant to hurt anyones feelings. Only to point out the obvious.

Sacrasm is just another FREE service I offer. Of course I failed to read the part where you couldn't remember where you read it, ha.

if it is the link above, I would say dchall is "the man" to ask or even bruce.
thanks for understanding.

    Bookmark   July 4, 2006 at 12:27AM
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gumby_ct(CT it says Z5)

Found this -
"Add 1 once of unsulfured molasses to provide a food source for the beneficial microorganisms."

Found here...

Here is a link that might be useful: or here...

    Bookmark   July 4, 2006 at 1:26AM
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annafl(z9b/10a Sarasota)

Thanks, Tammy. That's where I got it from!

Darkcloud, no apology required. My feelings don't get hurt easily. I think I will take your advice and see if I can ask dchall. Username 5 I'm sure is right, though.

    Bookmark   July 4, 2006 at 8:09AM
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dchall_san_antonio(8 San Antonio)

Here I am!

username was right. I used to hang with people who made 200 gallons of compost tea daily, 365 days a year, for a 500 acre farm. They are VERY into the details and use a microscope to analyze each batch of tea. They also use a "dissolved oxygen" meter to test the tea while they're making it. This is all very chemistry lab stuff. Anyway, water can only hold so much oxygen. Warm water holds less than cold water. Between 70 and 80 degrees F is when you start to lose so much oxygen that the water itself cannot support the beneficial biology. When the dissolved oxygen drops too low, you start to favor the anerobic (smelly and often pathogenic) microbes. When you add molasses, the bacteria breed like crazy, and with tea that is what you are shooting for. But you don't want to get rid of all the oxygen by growing too many microbes. This is why you want to aerate the tea. Tea temps in the 60s are really good for adding molasses and really multiplying the quantity of good microbes. At least this is what the professional tea folks tell me.

This probably clarified the issue for some and confused it for the rest.

    Bookmark   July 6, 2006 at 12:40PM
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annafl(z9b/10a Sarasota)

Dchall, thanks. I just made a batch of tea over the weekend and put a bit of molasses in it. It frothed up nicely and smelled good and fresh when I used it a little over 24 hours later. However, I remembered reading something about the temperature of the brew and not to use molasses if over 75 degrees. I'm sure my brew was in the 80's, so I won't use molasses next time. To resume the molasses in the late fall.

    Bookmark   July 6, 2006 at 3:42PM
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Ive used teas made up to 80 degrees or so. I use only a tablespoon of molasses for every two gallons of h2o. Base mix is 1/4 cup of my compost, 1/4 cup of earthworm castings, and 2 OZ. Alaska fish ferts. The micros that grow are producing verry quickly, feeding on the N from the fish ferts, and the small amount of sugar from the molasses. The key here is to only aerate for a time equal to the temp. If your aerating at 60 degrees, it takes much longer than at 70 degrees and so on. Your teas and oxygen availability can only support a microherd of a given size, over that then a massave die off happens. I always use molasses in teas, and have never lost a batch, but some are ready in 14 hours or a bit longer depending on the temp. Good Luck Root Doc

    Bookmark   July 11, 2006 at 1:55AM
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dchall_san_antonio(8 San Antonio)

You can always spray molasses directly on the soil or plants.

    Bookmark   July 11, 2006 at 2:55AM
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bobcat(z5 OH)

Can someone post a recipe for foliar feeding molasses on plants, namely tomatoes. Any wetting agents?

Does too much molasses in teas create alcohol?

And I have read MANY times that aphids cause mildew probs because they secrete sugars as 'honey dew'. Would not spraying molasses do the same?

What about honey?

    Bookmark   July 11, 2006 at 3:26AM
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dchall_san_antonio(8 San Antonio)

water is the wetting agent. I know of one commercial cotton farmer who applies 1 gallon of molasses per acre, 4 times a year. That translates to 3 ounces per 1,000 square feet. So if you measured out 1,000 square feet on your yard, poured 3 ounces of molasses into your hose end sprayer, filled it up the rest of the way with water, and sprayed inside your 1,000 square foot area until the sprayer was empty, then you would have applied exactly 3 ounces per 1,000 square feet.

I'm not doubting that you read what you read so many times about aphids, but I would like to see what a microbiologist had to say about the cause and effect of mildew. I have not had mildew on my roses in years, ever since I started scattering a heaping handful of corn meal on the soil under the roses a couple times a season.

I believe alcohol is the result of yeast eating carbohydrates. If you don't have any yeast in your tea, then you should not have any alcohol.

I would love to see some experiments using honey as a carbohydrate source. Honey has its own antibacterial components, so that would be interesting.

    Bookmark   July 11, 2006 at 8:30PM
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I just have to comment on what yousaid about corn meal on soil ina season. WOW! YOu are full of good information. It is great for us gardeners to do this. PROPS to you!

For everyone else, I had heard before where b/s molasses is so good for soil, gives minerals and microbes food. WEll, I have some echinacea insomewhat clay soil, not real bad though. ANyway, I noticed the flowers were so dull and lifeless (strange being that clay has good nutrients). I sprayed just a bit of b/s molasses on the soil and leaves, not much, and man after that, THe flowers were as gorgeous and bright as could be!
Just some food for thought (and microbes)! Thanks for the info. ~Karen, Ky

    Bookmark   February 20, 2009 at 10:51AM
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Even among the experts there is a lot of debate on some of these things.

The 'best' molasses - often called blackstrap, is the residue left after the third boiling to extract the refined sugar. It has a lot of trace minerals and many different types of complex sugars in it. Manganese, magnesium, iron, phosphorous, calcium.... all sorts of nice stuff that is left after the simple sugar is removed for processing.

As a disclaimer, I am NOT a recognized expert on the complex biology of aerated compost teas but I have some knowledge when it comes to aquatic systems after many years as a semi-pro fish breeding hobbyist. There are certain types of very sensitive fish from the soft, acidic waters of the amazon region and others from the hard water african rift valleys who need specific chemistries and that stuff I know cold.

Back to compost teas and molasses....

I've read volumes from the acknowledged experts regarding the ratio of fungi to bacteria to microbes over time at different oxygen levels and I get that stuff but I have to reject some of the stuff that is written because it is VASTLY over-generalized. The notion that dissolved O2, sugar level and temperature are the only factors is just silly. PH matters. Trace elements can be a limiting factor and the system is constantly in flux. If you pull a beaker of your brew and run it to your lab and then spend two hours analyzing it then the brew you come back to a couple hours later has changed dramatically.

Let's look at a simple example - the same experts who say that they are doing a detailed analysis say that certain organisms are doubling in number every 20 minutes. So if their sample has 16 representatives of 2 different organisms when they pull the sample then 2 hours later one of them may have doubled in number 6 times. 32 64 128 256 512 1024... so one or both of those 'critters' may be 64 times more concentrated than the analysis says or it may be wiped out because there is a bloom and crash cycle going on all the time. When one critter is multiplying exponentially it is not forever - eventually it hits a wall - all the food is gone, the O2 is used up or some trace mineral it needs is used up or the metabolism/excretion of the food has caused a massive shift in PH that makes another critter more suited to the environment and it is taking off as the first critter population crashes... and then some other critter starts feasting and doubling off the corpses of all the bacteria that just died off.

How does that work in aquaculture? Well, in a closed system you use bacteria to purify the water for the fish and inverts - a 100 gallon tank is tiny and chemistry changes very quickly compared to say an ocean, right? Fish peeing and pooping causes ammonia to spike and ammonia burns a fish's gills when PH is above 7 and everything crashes and your fishies die. They call that new tank syndrome. It takes a few weeks for even an expert to get the bacteria right because there is one type of bacteria that breaks poop down into ammonia, another that converts the ammonia to nitrite (also poisonous) and another that breaks the nitirite into Nitrate which feeds plants in the tank or is removed by water changes or by slow filtering the water through an anaerobic filter populated by the anaerobes that can break down the nitrate and leave you with clean water...

I know this is wayyyyyyyy more info than anyone probably wants but let me finally get to my point: The beauty of a natural system is that it will eventually balance out. If your tea goes anaerobic because some critter is using all the oxygen up and anaerobes start multiplying then what happens when the aerobic organisms crash? Well, oxygen levels start going back up and the anaerobes that cannot tolerate O2 levels above a certain level begin to crash and they are eaten by some other aerobic critter.

If you brew a tea that gets way too acidic or ferments into alcohol I can see it having a negative impact on plants that don't like that but once out of the brewer and into the soil any imbalance is going to self-correct.

I'm just starting to play with aerated teas and the results have been quite interesting and very positive. When I brew it up I am running two batches at once in separate containers. I start with a mix of well aged cow manure compost and a few pounds of nice, fungus rich broken down mulch and soil from under the bushes where there are lots of worms and such. I mix that up with dechlorinated water and stir it up several times then strain it with a mesh just fine enough to prevent my sprayer from clogging into two 5 gallon buckets as a starter then fill it the rest of the way with water. One gets a few ounces of horticultural molasses, the other gets whatever i find interesting that day - banana peels, some leftover oatmeal, the dregs of my wheatgrass, berry, protein, flax, chia smoothie I could not choke down despite the health benefits.... non sugary stuff....

I'll brew for a day, use up half the liquid in each one in the sprayer before or during a rain and then fill the buckets back up to replace the water and let them run for another day or two without adding anything and do it again and sometimes a third time. Replacing the water will dilute anything that has gotten too concentrated and I am sure that the biology of the 24, 48 and 72 hour brews in each bucket are quite different. I aerate them well but I don't bother measuring because I just don't buy into the idea that what's ideal for one area of the property or type of plant is ideal for all and I know for certain that 'ideal' a fallacy within any biological system that is undergoing rapid bloom/bust cycles. Once I spray it, the tea microbes are in a completely different environment and will undergo lots of changes very rapidly but the soil is going to develop a proper balance and figure the rest out on it's own.

Still reading? OK, so the point is that one way or another I managed to get all those nice trace minerals to my plants in a form they can use and if I am a little early or a little late then so what? I think if you ask ANY of the experts they would tell you that the biology of their tea when analyzed is different than it is if you spray it a few hours later. I also think they would tell you that it is hubris to even imagine that we can dial it in exactly but that is the beauty of using compost and the aerated teas - you don't need to get it right and you can't get it perfect but if you are somewhere in the right general zip code then the incredibly complex and only partially understood processes that have evolved over billions of years will take over and fix your mistakes.

...have been in current property for a year. When we moved in the property had been under the management of a service for several years, Weed sprays, insect sprays, fertilizer sprays... compacted, little evidence of worms. Now? Worms in abundance, neighbors hate my guts because they can't figure out how I get the Bermuda so dark green and lush and the beds and baskets are overflowing. Due to back surgery last year I can't spread truckloads of compost or turn a pile easily but I can make an aerated tea and I generate about a gallon of pee every day and you could putt on the lawn because I am one of those weenies who likes the bermuda at 3/8" and gets the dremel out to sharpen the blade every time I cut so that the clippings are tiny and break down into the tea-pee'd soil instantly :-)

Don't overthink it to the point of stressing out. It makes sense that you don't want to brew a tea full of salmonella or e coli by brewing up a batch of poop in the sun without aeration but otherwise it's kinda hard to go too far wrong with compost and/or teas with or without molasses because if you jack it up? Hakuna Matata baby - that whole circle of life kicks in and fixes your mistakes. Whether in tea or just mixed with water and sprayed on the turf, Molasses seems to have a huge impact on a lawn within a couple weeks. When plants are short on nitrogen they can excrete some sugar into the soil around their roots - what's that do? well the bacteria metabolize the sugar and they poop and die and release nitrogen. If you get 'too many' sugar bacteria into the soil and they fix too much nitrogen on Monday they will run out of food and die off on tuesday and become fertilizer for plants and food for other microbes. Nature figures stuff out so long as you hand it stuff that it made in the first place.

    Bookmark   May 12, 2014 at 4:16PM
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Quote fractions from the article below, just for information's sake:

…when done properly, compost tea will be a concentrate of activated microorganisms, more concentrated than compost itself. The process of making the tea allows the microbes to "wake up" and multiply. When you add this to your garden, you are adding a rich brew, teeming with creatures that will enliven your soil, and help it convert your dirt into a living biome. In short, the microbes eat and excrete. The excretion is plant food, and usually just about all a plant will ever need.

…I suggest using … compost, and depending on whether you want a bacterial or fungal brew, two tablespoons of non-sulfured molasses (bacterial) or two tablespoons of kelp powder (fungal)

Tea brewing is best done in the balmy, not too hot, not too cold seasons. Brew tea in the same temperature as the area you will apply the tea to, so outside. ... If temperatures are too warm, the tea will likely get anaerobic fast. If cooler, brew longer (up to about 48 hours). The water will be dark, like coffee. Again, use your nose and intuition.

Here is a link that might be useful: Dr. Weil

    Bookmark   May 12, 2014 at 4:47PM
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planterjeff(7b Grant Park Atlanta)

So I haven't started compost tea yet, but i do brew beer and too much sugar is a big issue when it comes to brewing. The thing is, both compost and brewing beer are a similar science as they both require fungal/bacteria growth to succeed. Sugar is a food for both yeast/fungus and bacteria. More sugar means more growth on all accounts, whether it is beneficial or enemy bacteria/fungus. In beer brewing you keep everything sanitized and air locked, BUT you cannot do that in gardening. So I am sure one risk is developing cultures of bad bacteria at the very least. Secondly, yeast converts sugar into alcohol and co2, which is why we use it in alcoholic beverages. But bacteria will burn oxygen and also release co2 when it eats the sugars as well and any natural yeast in the air will also release alcohol (which can be poisonous to plants). This could possibly be another issue for the plants; this and the fact that they burn a lot of oxygen. Who knows...

    Bookmark   May 14, 2014 at 3:50PM
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