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hank_mili

Compost Tea and Hydroponics

hank_mili
18 years ago

I was wondering if anyone has tried using aerated compost tea as the nutrient solution for his or her hydroponic projects with any degree of success. This forum did have a couple of links related to compost tea but there has not been too much discussion on the subject.

http://forums.gardenweb.com/forums/load/hydro/msg0608222826353.html

http://forums.gardenweb.com/forums/load/hydro/msg0802473426449.html

Comments (19)

  • willardb3
    18 years ago

    I have a worm farm and I feed them all kitchen waste and that makes very nice compost tea.

    I tried using it by adding to my hydro reservoir and got some nasty pathogens and biota plugged up my pumping system.

    I began to treat tea with H2O2 and the pathogens went away.

    No noticeable difference in growth rate, plant taste, fruit mass......stopped using the tea in hydro and now put it on dirt garden where it is hugely successful.

  • hank_mili
    Original Author
    18 years ago

    Thanks for sharing your experience with CT (compost tea) Willard. I was speculating about what happens to the microbes after the CT is made.

    The microbes either dies from lack of nutrients or lack of oxygen whichever comes first. The result as you have pointed out is a slimy mess.

    I was thinking of ways to mitigate this problem.

    1) The microbes can be killed (serialize the CT) and microbes removed or 2) maintain the microbes with food and oxygen to prevent them from dying.

    Either way though the need for a protein skimmer to remove the DOC (dissolved organic compounds, including dead microbes) would be necessary.

    Other questions related to CT, which I'll try to address in another thread.

    1) What is the nutrient content of CT?

    2) Can or should the CT be supplemented with inorganic nutrients and/or organic additives like humic/fulvic acids.

    3) What about EC and pH?

    Questions, Questions.

    Here's a helpful site on how to make CT

    http://www.dep.state.pa.us/dep/deputate/airwaste/wm/recycle/Tea/tea1.htm

  • willardb3
    18 years ago

    snip
    1) What is the nutrient content of CT?
    snip

    In the worm farm,

    {{gwi:996532}}

    Spunky says hello, dry worm castings are 2-2-2 NPK ratio.

    Tea is variable depending upon input, but is 3-1-1 when last measured. I send it to a lab who does the work.

  • hank_mili
    Original Author
    18 years ago

    Wow Willard that is very interesting information. Were they able to measure TDS concentration (PPM) or EC?

  • cavemangardener
    18 years ago

    Hi Hank Mili

    You have already heard that the tea is starved for oxygen, as it requires oxygen for the microbial population as well as the plant roots.

    Passive hydro is still hydro, though.

    Idea 1: Make your own soilless mix from peat and perlite at 1-1 ratio. Maybe add one cup of dolomite lime per cubic foot of mix. Put in well drained containers, and watch near hydro results as you water daily. As plants get larger, depending on container, you may wish to irrigate them automatically 2-3 times per day with the tea.

    Concerned about food for the microbes, or about them eating all the plants' food? Go to you local feed store, buy some liquid molasses, and feed it to your plants with the tea, or alternate. The sugar feeds the microbes and it has lots of micronutrients.

    Idea 2: watering coco coir daily should work as well. It looks like peat, but is more similar to rockwool. Organic feed methods work well in coco.

    With either of these, you could opt for dry molasses and mix it with you medium. One teaspoon per gallon for the liquid. Don't know about the dry. Grocery store bought molasses is just as good, but it's cheaper at the feedstore!

    Good Luck
    cG

  • willardb3
    18 years ago

    Putting sugar of any kind in a mechanical pumping system will trash any bearing, impeller, orifice, emitter and etc.....

    Not to mention crystallizing in the reservoir and on surfaces exposed to the sugar.

    I'll add the nutrients and let the plant make the sugar.

    Compost tea in a recirculating system does nothing once the biota are removed.

  • hank_mili
    Original Author
    18 years ago

    The sugar (molasses) is used to feed the microbes when making the tea. It should be depleted by the time the CT is ready for sterilization in say 2-3 days.

    Once sterilized the dead microbes and other large organic compounds in the CT need to be removed (with a protein skimmer maybe?).

    Hopefully what is left is "microbe excretions" in water or as we call it in hydro land "nutrient solution".

  • willardb3
    18 years ago

    Hank:

    I'll measure TDS of next worm-farm tea and post results.

  • willardb3
    18 years ago

    Worm farm tea is over 2000 ppm and off-scale for my meter.

    I credit this to the fact that it is winter here and the throughput in the compost is much reduced in winter.

    In summer, I add 20-50 lbs garden waste green stuff/week; in winter, it's lucky to be a pound or two. More oxidation, more water, more dilute tea......

  • hank_mili
    Original Author
    18 years ago

    2000+, that is much more than what I expected. That puts the EC around 2800+. I guess diluting the CT would be advisable. Great information thanks Willard.

    Going to try to make some CT in the next few weeks myself to see if I can get similar results. Thanks again.

  • hank_mili
    Original Author
    18 years ago

    Hi Caveman what is the reasoning behind mixing peat with perlite since perlite is inert?

  • cavemangardener
    18 years ago

    Willard:

    I don't know about granulated sugar, but I have used molasses in a reservoir with a mag-drive pump with no problems.

    Hank Mili

    The reason for the peat is that I am describing a passive hydro system that is hand or automatically watered at least once per day with compost tea. The perlite ensures plenty of oxygen. The peat holds moisture, and will allow the medium to act as soil where the microbes can continue to break down the organic stuff, obviating the protein skimmer.

    What I am imagining is a large barrel or trash can where the CT is made. Drop a venturi powerhead in there to move and aerate the tea. You will be stunned at how long an organic mixture will stay fresh this way. (at least one week) When it is time to water, dunk a can in and water the pots of perlite/peat, or use a sump pump, hose, and watering wand. (the latter is my personal choice)

    cG

  • hank_mili
    Original Author
    18 years ago

    Ah...now I understand. Somehow I was thinking you were using the perlite to make the tea. Sorry.

    My goal in starting this tread was to see if it was possible to make a pure nutrient solution from CT. I this context "pure nutrient solution" = sterilized CT with no microbes or large organic compounds in the solution. The idea is to use this processed CT as a substitute/replacement for normal inorganic hydroponic solutions.

    Here are the steps that I think needs to be done to get to this "processed" CT.

    1. Start making CT in the normal manner. Here is a good link for making CT:

    http://www.dep.state.pa.us/dep/deputate/airwaste/wm/recycle/Tea/tea1.htm

    Notes: Aeration is critical and giving some supplemental food sound like a good idea. Need to measure and record the TDS/EC several times during the "cooking" process to see when the TDS/EC reading starts to level off. This indicates the "food" is running out and/or the microbes are starting to die off.

    2. Sterilization. At this point it is time to kill everything. The idea is to prevent anaerobic activity and to stabilize the nutrient concentration. Sterilization can be accomplished by heating or chemical treatment. H2O2 is a good way but I was going to try an ozone generator in an airlift bucket. On a previous experiment using plain tap water and this setup an ORP reading of 650 was possible. At this level sterilization is achieved.

    3. Removing microbes/organic compounds. Short of a centrifuge I think a protein skimmer can be effectively used to remove the dead microbes and larger organic compounds. I think. This is the only piece I have not tried.

    At the end of all this work is hopefully something useable.

  • desade
    17 years ago

    Have any of you tried running a simple aerated system with the compost tea not a flood and drain or submersible pump type system? I have tomatoes going right now with sea kelp, alfalfa, and molasses and so far so good. I'm going to try something a little more potent.
    thanks for the ideas guys...
    Oh, take a look at the doctor dirt site. They have some good info on there. I hope that the link works okay.

    Here is a link that might be useful: doctor dirt fertilizer info

  • edurink
    17 years ago

    Here's something for the lighter side.

    Here is a link that might be useful: {{gwi:996531}}

  • mikey10
    11 years ago

    I can't find any references to using a frequent-flow worm tea as a hydroponic fertilizer. Just set up your worm bins in a row to be automatically watered several times per day and collect the resulting "leachate" or "worm tea" for use as your liquid fertilizer for the hydroponic system. You would need to add more or less worm beds depending on the size of your system. The worms can be fed shredded vegetable and fruit waste collected (probably free) from local grocery stores and restaurants. Or grow your own worm food in the form of Comfrey which worms love and is fast growing and highly nutritious AND Organic.

  • gordonace
    11 years ago

    I did a trial last year with CT alone on a bubbler. I grew some basil with very good result (big and healthy leaves and high grow rate). But the fresh CT must diluted (1:1, do not use tap water. The chorine in the tap water can kill the micros) before being used as liquid nutrient. Sometime, I just mix the old one with the pure fresh one (because the old one has been depleted).
    I did it without dumping the old ones for more than 4 months. They still grow fine. I still suggest to replace it every 2 weeks.

    I am currently experimenting on strawberry. They are still babies. To make the solution as weak as possible and organic, I am using the water from a planted fish tank. Will post update when their root establish.

  • Piet Maritz
    7 years ago

    Hi

    I'm new to the game of "ponics" I've been thinking in the same lines of using compost tea in a circulating system. In nature this works... I think... So I thought of having a sort of a inline system. Starting with a bio de-grader. It then overflows into a series of filters and is lastly oxygenated before going to the plants. The overflow is then returned to the start of the process. The amount of waste to be broken down can somehow be regulated after some study. Any nutrients still needed can be added in to the system. I'm not too worried about killing microbes as they are present in nature anyhow. Please comment.

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