Questions re: Compost Teas, etc..

[nao57]

So I'd been looking at videos and information on compost teas.... a lot of them start out that you grow bacteria and then throw in leftover weeds or greens that were cut from other plants. Then grow a reaction where the bacteria eats that and decomposes it. Then usually they say 2 weeks later you take say a few cups and add them to a bucket and then pour it onto your vegetable garden plants as a compost tea...

Since this ... compost soup is basically full of bacteria decomposing everything and most of the tutorials on those say you have it stewing for 2 weeks. Sometimes with or without sugar. But if there is sugar its supposed to be timed so that the bacteria eat up the sugar before it gets onto the plants in the compost tea form, The sugar they say helps calm down harmful bacteria and feeds growing the bacteria reaction faster to break down things quicker.
Like the reaction and theory on it seem very reasonable and logical. Often this is stated from KNF theories by a master gardener named Cho from Korea. But I have questions....
How does someone know that its going to be safe to use a compost tea, and not make the vegetables produced from it, unsafe to it? Its basically putting a bacteria composition reaction into a tea that you feed into the plants, so ... how do you know its not 'hot' for humans to use? And is there a cool off period where you have to let the plants settle what was fed into them before humans can eat or pick those vegetables or fruit? How do you know the bacteria isn't too hot to use?

And is there a certain time it takes for the vegetable plant to process any bacteria in the compost tea applied to their roots also?

 

[Soiled]

I've never been quite convinced about the practice of compost tea. If you want compost bacteria on your growing beds, just put compost on, water it, and it'll make it's own tea. Soil is FULL of bacteria, both good and bad. If the plants we eat took up bacteria regularly through the roots, they’d be full of pathogens and we’d be sick all the time. You eat plants that are stewing in the stuff, so they know how to keep themselves clean. Certain kinds of plant pathogenic bacteria can bore their way into roots and make plants sick, however. But these are not human pathogens. There is also some indication that plants can consume microbes as a source of nutrients, but the digestion of them takes place in the roots.

 

[roadrunner]

I just chop and drop and allow the soil organisms do the work for me. I'm definitely not going to waste my time doing the aeration of making compost tea.

I do know a guy that simply throws organic matter in water and allow it to form a tea and of course it's a very stinky anaerobic concoction, but he gets good results, he says it's a waste of time to do the Elaine Ingham method -- I agree. And using a microscope is silly.

 

[smitty55]

I've never been quite convinced about the practice of compost tea. If you want compost bacteria on your growing beds, just put compost on, water it, and it'll make it's own tea. Soil is FULL of bacteria, both good and bad. If the plants we eat took up bacteria regularly through the roots, they’d be full of pathogens and we’d be sick all the time. You eat plants that are stewing in the stuff, so they know how to keep themselves clean. Certain kinds of plant pathogenic bacteria can bore their way into roots and make plants sick, however. But these are not human pathogens. There is also some indication that plants can consume microbes as a source of nutrients, but the digestion of them takes place in the roots.

The thing is a properly prepared actively aerated compost tea compounds the amount of bacteria by thousands of times so within 3 days of aeration and molasses to feed them you'll have a huge amount of beneficial bacteria ready to use right away. Aeration is essential as most pathogens are anaerobic.

 

[Oliver Buckle]

I have a bucket of manure with holes in the bottom that water filters through and use it on my tomatoes when they start to flower. The plants will be after the nutrients the bacteria liberate, the bacteria are far to big and complicated for them, so they will never enter the plant. I suppose there is a possibility of splash, remote watering tomatoes, but always wash veg anyway before you eat it, look what accumulates on your windows, or car, in the time it takes for plants to grow.

 

[Oliver Buckle]

I thought I would check myself, an e-coli bacterium contains an estimated fifty billion atoms, the things plants absorb dissolved in water are simple, a molecule of urea, for example, contains eight atoms.

 

[Soiled]

The thing is a properly prepared actively aerated compost tea compounds the amount of bacteria by thousands of times so within 3 days of aeration and molasses to feed them you'll have a huge amount of beneficial bacteria ready to use right away. Aeration is essential as most pathogens are anaerobic.

Properly aerated and moistened compost is going to make loads of bacteria in situ. Why take the trouble to make tea? it's a lot of effort. Once you put compost tea in the garden, if the garden isn't full of sugar, the extra bacteria will just die anyway.

 

[Oliver Buckle]

Once you put compost tea in the garden, if the garden isn't full of sugar, the extra bacteria will just die anyway.

To be fair, if they do they will release more nutrients the plants can access, though it is only a one off, bacteria living in the soil will continue breaking complex substances down, and reproduce.

 

[Oliver Buckle]

Like the reaction and theory on it seem very reasonable and logical.

Be careful of the reasonable and logical, most natural systems are chaotic, if something can happen, then sooner or later it will. This means that all the possible order systems are contained in a chaotic state, we are very good at spotting order systems, less so at spotting they are not always the only possibility.

 

[Soiled]

To be fair, if they do they will release more nutrients the plants can access, though it is only a one off, bacteria living in the soil will continue breaking complex substances down, and reproduce.

Not sure that makes sense. Bacteria in themselves are not nutrients, or at least not any more nutritious for the soil than compost, which is only marginally nutritious with most nutrients. (The NPK of compost is not high.) Bacteria in soil are good because they help break down organic matter (the compost). There is a lot more compost than bacteria, and the NPK of bacteria is probably no higher than compost. I have to assume that if you dump bacteria on soil that has already formed a lot of bacteria up to the limit the soil will support, that extra bacteria likely won't survive.

 

[PGB1]

I'm not an expert gardener, so take the below with that in consideration. I'm just presenting this as an easier-than-tea method to consider.

Over the years, I've experimented with compost teas made by various methods and with various ingredients. I've also used hummus and used various organic fertilizers. They each have happier plants than untreated areas, but not by much. This year, I tried something different & the results surprised me.

Last fall, I raked the maple trees' leaves into large piles and ran them over with the battery lawn mower. They got chopped into tiny bits. I piled that all up and left it outside over the winter.

This year, I divided my garden into 3 areas.
On one area, I did nothing. On another, I laid about 2" of the damp, now oatmeal consistency, worm laden leaf bits on the soil. On the third, I worked 2" of the bits into the top few inches of soil.

About one week after I did this, the plants in both areas with the leaf bits had grown by leaps and bounds over the un-treated areas. The one where the bits lay on top (not mixed in) stays wet longer than the mixed in area and much longer than the untouched area. The area with the leaf stuff on top has fewer weeds. Worms, butterflies and bees like those areas also.

The plants (various tomatoes & peppers) in both treated areas are noticeably stronger than the untreated area plants. They are quite a bit taller & stand straighter as well. There are many more fruits, too.

I think I'll abandon compost tea and organic fertilizer in favor of the leaf mess.

Paul

 

[Soiled]

With regard to compost tea, if it really increases productivity, you have to wonder why commercial farmers don't do it. Many DO use compost, but I've never heard of compost tea being an accepted commercial strategy. I might believe if one or two farmers were trying it, but if it were really a productive practice, everyone would be using it. Commercial farmers are extremely sensitive to practices that improve productivity.

Last fall, I raked the maple trees' leaves into large piles and ran them over with the battery lawn mower. They got chopped into tiny bits. I piled that all up and left it outside over the winter.

Yep, I use leaf compost routinely. Wonderful stuff for soil friability and moisture retention, though the N content is near zero. Manure compost at least has some nitrogen.

 

[Meadowlark]

...The NPK of compost is not high....

A generalization which is patently false in my compost.

Test results for my compost:

Nutrient	Your Results	Optimal Range	Rating
pH	6.37	5.8-7.0	Optimal
Total Nitrogen (N)	38.91	32.0-60.0	Optimal
Nitrate (NO3-N)	30.14	-	-
Ammonium (NH4-N)	8.77	-	-
Phosphorus (P)	31.59	8.0-20.0	High
Potassium (K)	114.79	38.0-80.0	High
Sulfur (S)	9.92	7.0-22.0	Optimal
Calcium (Ca)	83.01	80.0-320.0	Optimal
Magnesium (Mg)	33.68	27.0-70.0	Optimal
Sodium (Na)	13.81	0.5-30.0	Optimal
Iron (Fe)	1.27	3.0-10.0	Low
Manganese (Mn)	4.7	4.0-10.0	Optimal
Zinc (Zn)	0.17	0.1-0.25	Optimal
Copper (Cu)	0.03	0.06-0.3	Low
Boron (B)	0.01	0.2-0.6	Low

Test summary: No N P K required

 

[Soiled]

Please quote your NPK. "Optimal" and "High" mean nothing with regard to NPK. If those are ppm numbers, the NPK will depend on the dilution used. Those rating words in such tests usually refer to soil. So if your compost is as good as very good soil in N, P, and K, that's not saying much. You haven't addressed my comment explicitly. You can look here - https://www.gardenmyths.com/compost-fertilizer-numbers/, or look up just about any assessment of compost NPK. Everyone says compost has minimal NPK. That's not to say compost isn't good. It's wonderful. But just not as a powerful nutrient.

 

[Meadowlark]

Everyone says compost has minimal NPK.

Another patently false generalization.