is this compost tea?

Pulaski, GA

I left a 5 gal. bucket that was half full of homemade compost outside in the rain last spring. It filled up with water and I forgot about it until today. Would the liquid be considered compost tea? Thinking about using it to fertilize my fall vegies.

Orlando, FL(Zone 9b)

hmm, it sounds like it would be. but, it might be best if you still diluted the doses with regular water.

Anna, IL(Zone 6b)

Sounds like it has probably diluted itself by now and even if it hasn't it is sure worth a try on your fall veggies. If it was manure tea, it might need more diluting. That reminds me I have manure to I need to use.

Everett, WA(Zone 8a)

The main virtue of compost tea is the microbes that grow in it while fresh and aerated. Wet compost in an unstirred bucket would quickly go anaerobic and ferment, which produces slightly toxic acids and alcohols. Not great for root hairs, but not really toxic.

The thing is, it is almost "anti-compost tea". Keeping tea aerated while it ages encourages aerobic microbes that are thought to be (on average) good for plants and soil, and even able to compete with some plant diseases, for example on leaf surfaces.

By collecting anaerobic compost, you're encouraging microbes thought to be unwanted in soil and on leaf surfaces!

Miles, what you had was not "compost tea", just old wet compost that sat anaerobic for too long. If someone is in the same situation, I would suggest dumping it somewhere it won't discourage any young roots. Let it drain out and get some air for a week or two. Scratch it around to break it up, every few days. rain will leach out organic acids and alcohols quickly. Then it is OK to use as compost.

Or just put it in your compost heap and mix it around so it can re-aerate and inherit a better class of aerobic microbes.

If you want it to go into your garden ASAP, i would spread it thin on top of the ground and just break it up with a rake. If you must mix it into the ground right away, go no deeper that one inch, so it can get some air!

Plantersville, TX(Zone 9a)

A person has to be careful with standing compost teas, that is not aeriated. I once poured some on my plants, & they died.

Everett, WA(Zone 8a)

I was surprised that all it takes is some stirring or pouring back-and-forth to keep it aerated.

But I guess some oxygen is absorbed right through the water surface.

Edmonton, AB(Zone 3a)

I am going to try aerating some compost to make "Compost Tea". In the meantime, I have mixed my compost in a 5 gallon pail with rainwater and let it sit for a few days without any negative impact on my flowers. That being said, I didn't notice any benefit to them either. This is why I am going to try and set up a true compost tea brew kit - with aeration and food for the bacteria. I'll let you know how it works out.

Everett, WA(Zone 8a)

Brewing it in a shady or cool area might help with the oxygenation. More oxygen dissolves in cold water than warm water.

Maybe it will also be absorbed faster when the water is cold or cool.

Just scooping up a gallon or two and pouring it back in from a height each time you walk past will help some.

Maybe a second bucket, propped up above the first bucket, with a small hole drilled in the side of the upper bucket. Scoop and pour most of the water in the lower bucket into the upper bucket each time you walk by. Aim the stream of water from the small hole into the center of the lower bucket.

The water will be aerated when you fill the upper bucket, and as it streams through the air, and it will carry air bubbles into the lower bucket as it streams in.

Just speculations.

P.S. Birds and animals seem fascinated by the sound of dripping water, and may try to drink from the stream.

Orlando, FL(Zone 9b)

This seems like the perfect thread to ask this - what do I do about rainwater that has algae growing in it?
The rainwater has been collecting, from every rainstorm since maybe November, in a 5 gallon bucket. I did not purposely collect the water but I don't want to let it waste. I figured it isn't a good idea to directly water the plants with standing green water because maybe the oxygen levels are low now that the algae has been growing or something.

Anne Arundel,, MD(Zone 7b)

When I find algae water, I assume it has nitrogen when used, due to the green stuff in it. I would stir it up (get air into it) and use it.

Everett, WA(Zone 8a)

I think you can use it just fine unless your soil is REALLY heavy clay and has very poor structure and almost no drainage or aeration.

The oxygen in soil with any "structure" comes mostly from gas diffusion through open pores and channels in the soil. Gas diffusion in a gas is a very fast process. If soil is well drained it is probably also well aerated.

Maybe some of the oxygen in very poorly draining soil with almost no "structure" comes from gas dissolved in the water that trickles through the soil.

However, that seems like such a slow process that soil life and roots would extract the dissolved oxygen rapidly and then suffocate. When there are no open pores or channels, or they are filled with water, the way for O2 to get from the atmosphere to the root zone is to dissolve into surface water, and diffuse through water (capillary water mostly) until it reaches the roots. That is really slow.

Unless water drains continuously THROUGH the bed, constantly bringing new dissolved O2 with it.

I should admit: that is just my belief and unproven speculation.

Orlando, FL(Zone 9b)

Thanks, I stirred the bucket for a minute or so a couple times a day since. The algae isn't gone of course, but looks less sickening.

Good idea with the soil structure. It's reassuring because I have Florida sand, and drains well and/or dries quickly in the sun. Once I use the water nature should take care of the rest.

Everett, WA(Zone 8a)

>> Florida sand

You're fine. Super-well aerated "soil".

I think that is part of the problem with FL soil. It is SO well aerated and year-round warm that anything organic that you add gets digested by the microbes almost faster than the bugs can eat it.

P.S. Algae totally needs light. If you can give that bucket deep shade, you should have less algae (after it dies back and something digests the dead algae). Also, shade - cooler and cooler = more dissolved oxygen and slower bacterial metabolism = more dissolved oxygen left over.


Someone said that a little copper (very little) will keep algae from growing in a bird bath, and MIGHT not poison the birds. They discussed how much copper is too much for birds.

A really old penny (pre-1984??) or a short length of copper tubing is plenty to discourage algae. However, if you have acidic water, the copper will dissolve faster than usual, and you might have to wonder about how much copper is "too much".

Anne Arundel,, MD(Zone 7b)

"I think that is part of the problem with FL soil. It is SO well aerated and year-round warm that anything organic that you add gets digested by the microbes almost faster than the bugs can eat it."
I've kind of concluded that also, after hours of mulling over my sister's garden in FL.
They say that a leaf that falls to the rainforest floor only lasts one month.

Orlando, FL(Zone 9b)

Thanks for all the great information Rick and Sally!!

I'm glad for this reassurance about my FL soil, I mean sand haha

It still takes a lot of bagged soil, compost, etc to balance out the amount of pure sand though.

Now I can use my rainwater which I didn't even plan on collecting! It is now in full shade, and I don't see the same thick green anymore, plus we are in for rain so that should "refresh" the bucket.

Another member also advised me to add the pennies to the birdbath, although I don't have a birdbath yet - It definitely makes some difference in public fountains!

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