Compost Tea Question

[fleemo17]

I tried my hand at brewing some compost tea, but I think my pump was too weak. The tea smells terrible. It's been "brewing" for about two weeks now. I just added a new pump, but I'm wondering whether I should just start from scratch or whether there's hope for this batch? Might the beneficial microbes have already died by now?

[Billy]

How big was your container and describe your pump.

[Jangchub]

Aerobic compost tea should not brew more than 36 hours and should be used no longer than a day after it is brewed.

[Buderschnookie]

Two weeks is indeed to long. I forgot about a batch for just a week and it like to knocked me down when I remembered to check it. Toss it somewhere you don't have to smell it :)

[Tad]

What you're smelling is the production of anaerobic organisms. They create smells similar to vomit, urine, or alcohol. DO NOT USE IT ON YOUR PLANTS. You could potentially do some major damage to your plants. Good actively aerated compost tea should smell slightly earthy or have no smell at all. The same goes for the compost you use initially.

Here's a good starting place for information:

a great book is for beginners is "Teaming with Microbes" by Jeff Lowenfels.

What were your inputs into your container? What size pump were you using? There are many more variables to making good compost tea that most people realize. Hope we can help!

~Tad

[fleemo17]

Thanks for the replies.

The original pump I used came with a 5-gallon aquarium tank. I used a

5-gallon bucket to brew my tea so I thought I was in good shape.

Here's the process I used: I filled a 5-gallon bucket with water. I took the aquarium pump and attached gang-valves to four separate bubbling stones. I turned on the pump and let it run for a day to eliminate any chlorine in the water. Then I put some nice, sweet- smelling finished compost in a cheese cloth and set it on top of the bubblers. So the beneficial bacteria could have a little chow, I added a few teaspoons of molasses and stirred twice a day. It began to foam, but man did it stink! So, where did I go wrong? My only guess is that the pump was too wimpy to aerate the brew. Or perhaps that I put the compost in cheese cloth instead of just dumping it in the bucket? I hate wasting perfectly good compost, so any advice before I try again would be appreciated.

Oh, and can I dump this awful concoction back on the compost pile?

[Billy]

Basically I'm in agreement with Tad but I'm wondering about the wisdom of putting the compost in cheese cloth. I would remove the cheese cloth, add a little more molasses, and pour the brew into another container and continue aeration. Repeat pouring into another container for three to four days. If the smell does not improve, return it to the compost pile and start from scratch again without the cheese cloth. This is a good time to practice as, at least in the northern hemisphere, where the ground is cooling down and you can't expect too much growth from your plants anyway.

[Tad]

Okay, a couple of things:

1. I would not dump this material back onto your compost pile. Basically, you've established that you've brewed up a bunch of anaerobic organisms that you don't want on your plants. So why inoculate your compost with them? Better to dispose of it and start fresh. Did you know that plants can't tolerate alcohols beyond 1 part per million? There just isn't room for these organisms in a healthy soil food web, and you certainly don't want to introduce them artificially through bad compost tea.
2. I have not seen any data supporting the use of cheese cloth. I do know for a fact that 400 microns is the optimal mesh size to put the compost into when using a mesh bag. This allows the fungi and protozoa to escape, but keeps most of the particulate in the bag. You can brew without any bag at all, as long as you have adequate aeration so the compost doesn't just settle at the bottom of the bucket.
3. Aeration is key! You need to keep the dissolved oxygen levels above 6% throughout the entire brewing cycle. This isn't easy to measure without a meter, but to give you an idea, in our brewer we are raising the water column over 2 inches. This means that when I turn on the aeration, the water level is raised up over 2 inches higher from the bubbles.
4. How much compost did you use? I use 1 heaping cup that is a combination of 3 composts: vermicompost, alaska humus, and a fungal compost. This increases the diversity of organisms and ensures that I have a good starting group of microbes. All the composts have been lab tested, so I know they contain the organisms I want. You may want to consider adding another compost, but all you need is maybe 2 cups total or 1 lbs. worth.
5. Molasses is a complex sugar source that tends to select for bacteria. The fungi are what provide the disease suppression and many of the other beneficial functions. Do you have any humic acid or liquid kelp?
6. Air stones can be problematic. Make sure you clean them thoroughly with hydrogen peroxide and wipe off any remaining biofilm. Otherwise you'll sabotage your next batch before you even start brewing. Data has shown that very little biofilm can significantly reduce the levels of beneficial biology in your tea.

I know this is a lot of info. There's a lot that goes into making the tea. Hope this helps though, and check out that link I posted!

~Tad

[jeff]

Wow, two weeks brewing???? You ran out of food for the organisms a long time ago. Dump it out. Clean up and start over again. Try it first with just a teaspoon of molassas and 24 hours.....

Cheers,

Jeff Lowenfels Teaming with Microbes: A Gardener's Guide to The Soil Food Web....

[fleemo17]

the ground is cooling down and you can't expect too much growth from your plants anyway.You may want to consider adding another compost, but all you need is maybe 2 cups total or 1 lbs. worth.Do you have any humic acid or liquid kelp?

[Billy]

Yeah, optimum temps for yeast are around 95 F. I'm guessing that the same would be true for the other micro-organisms. Tad is right about the alcohol but I have a hard time believing that you could be anaerobic with an air pump, except at the center of your cheesecloth. You could add the material back to your compost as the anaerobic organisms won't survive the aeration. But you avoid all problems, if you just chuck it.

Try same approach again for a week. Pour bucket to bucket (as needed), for additional aeration, if you detect off odors. Filter through a nylon stocking, cheesecloth, or towels (cotton or paper), if you are planning on spraying it as a foliar application.

What the hell you going to use it on at this time of the year? Using a greenhouse?

[Tad]

where the ground is cooling down and you can't expect too much growth from your plants anyway.

over 2 inches higher from the bubbles.

cups total or 1 lbs. worth.

I have say, I am impressed with your tenacity! We'll get you making quality compost tea I'm sure! I'm in agreement with Jeff about starting over and brewing for somewhere between 24-36 hours. And less is more when it comes to adding addition foods for the microbes in your tea. Too much molasses and your tea can go anaerobic in a matter of minutes, even if you're pushing a lot of air into your bucket.

Homemade recipes I've seen from Dr. Ingham called for some humic acid and liquid kelp and maybe a little molasses. I can dig up the recipe if you'd like.

As for optimum temps., you want to brew at the ambient temperature you'll be applying the tea at. It makes sense really, you're selecting for the organisms that are most successful at that particular water temperature in your tea, so you want it to match the temps that you're applying at. Optimum temps are 70-85 degrees F., though you can brew at up to 95 degrees (though you will need to cut back on your foods). From 50-60 degrees F., you may need to increase your brewing time and also add more foods, as the organisms will be slower to reproduce.

As for filtering, I haven't seen any data relating to the use of cheese cloth. Jeff, maybe you can help here. I know Jeff recommends the use of large-size nylons (I can't remember the specific size that fits over the bucket). I assume that would be larger than 400 microns when stretched, so any fungi and protozoa should be able to make it through the filter. You don't want the filter to be catching your larger beneficials though, so make sure you're not straining it too finely.

I know in Florida this time of year, many people are using the tea. Here in Seattle, we're done spraying for the year. We typically try to get one last application down on the leaves that have fallen and been mulched to speed up their decomposition over the winter and increase the organic matter in our soil come spring time.

By the way, I don't mean for my posts to be discouraging in any way. I think it's great that you're giving it a shot in making the tea. I really am talking about optimal conditions with everything I'm listing. You may not be maximizing the extraction and replication of these organisms in your brewer, but that doesn't mean it won't be beneficial. I say go for it and experiement. Try a few different recipes on the similar plants or patches of your yard and see how it responds. If you want to get really scientific, you can send in a sample to Soil Food Web or look at your tea under a microscope. Where are you located? If you're close to Seattle, you can send me a sample and I can take a peek at it for you.

~Tad

[Tad]

where the ground is cooling down and you can't expect too much growth from your plants anyway.

over 2 inches higher from the bubbles.

cups total or 1 lbs. worth.

Here's that recipe I was talking about from Dr. Ingham:

5 gallon brewer 1 lb. of compost (I tend to prefer volume, as weights will vary with moisture) 1/2 cup of humic acid 1 to 3 T. of kelp 1 teaspoon of non-sulfured, blackstrap molasses

Check biology when you are done. If fungi are too low, up the humic acid or lower the molasses

Bacteria and fungi compete for food. High bacteria mean low fungi, unless you get the right balance of foods for them to both do well.

[Billy]

Upon further review, I suggest temps in the 70F - 86F range and a fermentation period of three days. If the tea brews for more than three days, add more molasses.

[fleemo17]

Just wanted to say *thanks* for all the careful input folks have offered here. I truly appreciate it. Armed with this knowledge, I hope to have a killer batch of compost tea!

Have a great holiday season. :)

[Tad]

Good luck, and keep us posted on how it goes!

~Tad