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Compost tea as a hydroponic nutrient

Posted by greystoke Mediterranean (My Page) on
Sat, Aug 4, 07 at 5:42

I don't know if "traditional" compost tea can be used in hydroponics. The tea boosts a variety of micro organisms which are beneficial to soil-based cultures, but there are numerous warnings that it can also introduce disease this way.

I'm not interested in micro organisms and I also doubt whether they are of direct benefit to the plant. I think the tea contains organic substances which stimulate growth and immune responses in the plant.

However, I can't find an authoritive article on the subject. Every one sings the tea's praises, but . . . what exactly for?

Does anyone have an opinion on this ?


Follow-Up Postings:

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RE: Compost tea as a hydroponic nutrient

I have a worm farm and, as a result, plenty of compost tea.

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Tea used untreated in hydro will get you lots of biota that will plug up your liquid passages (pumps, pipes, etc.)

There will also be pathogens in the tea that you don't want.

I have sterilized tea with hydrogen peroxide and my notes indicate no change in the chile plants or fruit over time.

I put the tea on the dirt garden with great effect and the worm juice last tested at 3-1-1 NPK ratio.


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RE: Compost tea as a hydroponic nutrient

That's very useful information. Wont the peroxide affect the beneficial organics in solution? What is the concentration?

A surprising high N-content!


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RE: Compost tea as a hydroponic nutrient

The nutrients in worm tea as in compost tea are going to vary depending on the feed/bedding for the worms or the input into the compost.

The peroxide probably would kill the beneficials as well as pathogens.

The reasons for singing the wonders of compost, worm castins and teas brewed with those substances is that the beneficials in them improve the soil and healthy soil naturally grows better plants. Just because these substances are wonderful for organic gardening, does not mean they are much help in hydroponics which so far has not figured out quite how to be organic.

There are a few interesting ideas floating around out there for organic materials being made into hydroponic nutrients but so far I'm guessing it might be easier to use those materials for regular organic gardening.


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RE: Compost tea as a hydroponic nutrient

I am repeating this post here, as I accidentally posted it in the wrong thread.

Im beginning to realize that some of the benefits of compost/worm tea may well be lost on hydroponics, in which case it may be better to stick to soil-based cultures.
On the other hand, there are plenty of reports showing the response to foliar sprays. This means that the tea contains organic compounds that are readily absorbable by the plants. Compounds that are absent in base-chemical nutrient solutions.
This makes me believe that there is still merit in pursuing this.
In any case, I realized that it would have to be a two-step system.
1. A bin producing compost.
2. A system to leach-out the beneficial compounds, and sterilizer (A UV-steriliser?)
 African Sunset


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RE: Compost tea as a hydroponic nutrient

Hello all, I am trying to set up a hydroponics system for some high school students and I was thinking of using compost tea. I'd appreciate any ideas, suggestions.

For the hydroponics system, I was thinking of a raft type: plants in styrofoam blocks floating on the growing liquid (with aeration).

For the growing liquid I am thinking of using:

1. Real hydroponics solution as a control for the experiment.

2. Diluted compost tea made from general purpose compost.

3. Diluted compost tea made from partially compost garden waste with and without kelp meal. Basically, allow the garden waste (grass & weeds with/without kelp meal) to compost for 1-2 weeks then make the compost tea.

I am thinking of making the compost tea by simply mixing the compost with dechlorinated water. I am might particular worried or care about the micro-organisms in the compost tea, I just want to extract the water soluble plant nutrients.

Anyone think this will work? After since compost has all the nutrients for plants, wouldn't an extract of it work as hydroponics liquid?

Gerry


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RE: Compost tea as a hydroponic nutrient

Hi Gerry,

That raft system is a good idea. Do you have an EC-meter? Because you would need to dilute your "tea" to the same strength as the control nutrient, and preferably also the same pH.
I am going to undertake something very similar, but until now Ive been given to consider so many potential problems, that Im pretty confused.
For instance:
The organic matter needs to be properly digested to make the soluble nutrients available. But how much will there be? Also, you can expect it to be somewhat deficient in phosphate and magnesium, so you need to "spike" the compost heap with bone meal and dolomite. But how much? And then, if the compost has been kept too wet (heavy rains) it will have lost all of its potassium. Potassium is very volatile.
Finally, theres the problem of pathogens from garden waste (dog pooh, etc)

Originally, I was going to intermittently spray the compost heap with water from the collecting drip tray in a re-circulating system. Then I thought of making a two-step system which makes properly digested compost first, and then leach it to make the tea.

Now, Im back on my original plan, because I saw a system in operation whereby kitchen and garden waste is thrown into a pond which connects to a fish rearing pond (tilapia) A small pump keeps the water circulating from waste pond to fish pond and back.
The waste nutrients feed micro-organisms, which feeds small organisms such as daphnia, which feed the fish.
Very clever!

Regards
Greystoke


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RE: Compost tea as a hydroponic nutrient

Hi Greystoke,

Thanks for EC-meter idea. We want to compare compost teas to real hydroponics solution, so we have to make sure they are at the same strength. Also, we will be growing the same plants in soil as an extra control.

The aim of this project is to determine whether we can make a "simple" hydroponics system using garden waste (that is, only grass and weeds, no kitchen or animal wastes). Can we make a system that people use their garden waste to grow plants hydroponically? If we assume that most people do not have EC/pH meters and precise measuring/weighing equipment, we are a bit limited by what we can do. (I am part of a university in Ireland and have all the equipment we need, the point is to make a system where we do not need to use them).

This all comes out from an experiment I did years ago in Greece. I collected seagrass (Posidonia oceanica, similar to seaweed) from the beach - it was a mixture of fresh and dried. Washed it to get rid of the salt and sand and freeze/thawed it once to break open the cell walls. I then dumped it into an aquarium (about 1/5 seagrass to 4/5 freshwater). I used that water to grow tomatoes, basil and peppers. Compared to similar plants in soil, it worked fantastic - and that was with no equipment to test EC or pH.

Now in Ireland, I want to make a similar system using garden waste.

In this high school project we are going to take fresh garden waste or waste mowed within, say, 2 weeks. Mince it in a meat mincer and then put it in a raft type hydroponics system. With the general purpose compost we will simply dilute it in the water. The EC meter should help with guessing how much to add in.

By the way, the tilapia system you mentioned is the prime example of "polyculture" aquaculture, practiced in China: tilapia/carp grown in a rice paddy, their wastes are eaten by ducks, those wastes help the rice grow.

Gerry


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RE: Compost tea as a hydroponic nutrient

Is the EC meter going to have much to read in compost tea?

I like the idea of using compost and worm compost waste to feed plants. I am interested to hear about the results of your experiments.

It isn't really like hydroponics but some of the permaculture methods where plants are planted in mulch might be similar to Hydro if you were watering with worm/compost teas. Mulch is more likely to support those microbes rather than killing them off.


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RE: Compost tea as a hydroponic nutrient

Wow Gerry, you've given me a lot to think about!

I've collected a lot of info on leaf analyses of various plants, and I've done a little exercise:

Young grass cuttings contains () 2% N, 0.25% P, 1.5% K, 0.25% Ca, 0.2%Mg and 0.15% S.
If you were to put 75g in 10L of water, you would get a nutrient solution consisting of:
150ppm N, 19ppm P, 113ppm K, 19ppm Ca, 15ppm Mg and 11ppm S. All assuming a 100% extraction rate.
That's not bad for such a simple operation, but as a hydro nutrient it is somewhat deficient in P, Ca, Mg and S, which leads me to believe that - if you use grass cuttings - you need to supplement the "broth" with say: bone meal, dolomite and a pinch of epsom salt.
What you think?

Hi tclynx,
I think that if the broth contains nutrients that are available to the plant, then there must be an EC reading, and that reading is indicative of the nutrient concentration thus obtained.


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RE: Compost tea as a hydroponic nutrient

Hey greystroke, let me just add my 2 cents. The measurement from the ec readings will be off. Ec measures salts, or more so the electrical charge of the solution. The problem is that not all organic nutes are in a salt form, therefore wont add to the reading. Doesnt mean that they arent there, you just cant see them with an ec meter. Second, if you use the tea in hydroponics, you will need microbes to break the stuff down. That can be acheived in hydro, as long as it is an active system, which means pumps, air stones, ect. The new improvements in the mycorrhiza scene made way for them to be used in active systems where aeration of the nutes is constant. They will colonize the roots quickly, and when the organic solution is run through the system, they will grab the particles, and digest them into plant usable compounds.On the other hand, a lot of the compounds in worm castings are readily available already, so at least some of the good stuff will be used right away, without the microbes. I have tried tea as a foliar spraY, BUT YOU MUST WASH THE PLANT SOON AFTER IT DRIES. Every time I used it, I got this brownish film, that was more than a little stinky the next day. Either way, I probably could have ended this sooner by saying its a great additive, but as you said is low in other goodies, so should not be used alone.


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RE: Compost tea as a hydroponic nutrient

darthhelmut,
but then the tea was not fully digested, and you're relying on a post-composting process to digest the last bits and pieces.

By-the-way: thanks for the link on "oxygen near the roots"

Regards
Greystoke


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RE: Compost tea as a hydroponic nutrient

Thanks for the analysis greystroke. I will have the students look into the calculations and how much we will need. I don't think they have decided which type of plants they will grow.

Also, not sure about using bone meal - it has a real bad name here in Ireland/UK due to the "mad cow" BSE crisis. The dolomite might be worth trying.

By the way, I was reading the hydroponics entry in Wikipedia and I had one of those light-bulb above the head moments. OF COURSE compost tea can be used as a hydroponics solution. Extracting soil or compost with water and using to grow plants is the ORIGINAL proof/basis of hydroponics done by Sir Francis Bacon in the 1600s. It shows that you do not need the actual soil/compost, just the water soluble bits for plant growth.

If you boil the extract you can then demonstrate that the micro-organisms are not needed for plant grow either.

Hoping to start our experiment in the next few weeks. I will post any results as they come in for anyone interested.

Gerry


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RE: Compost tea as a hydroponic nutrient

Concerning Teas - have you tried adding humic acid to your brews?

Would anyone suggest, which Im leaning towards, was using organic compost teas in conjunction with any quality products and regiment? ie :advanced organic hydro program joined with supplemental teas for its benefits concerning diseases, root clean up, and its foliar benefits(disease reduction and absorption)

Im forced to go hydro I feel because the state Im living in is constantly changing its laws - hydro is the only way to achieve high yield? Is the conclusion I've been coming to - what do ya'll think? id much rather stay with dirt but am trying to also achieve high yields?!?!
Thanks


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RE: Compost tea as a hydroponic nutrient

Hello, I have had great results with Vermi-T. I add it to every batch of nutriets I mix up. Both soil and hydro (coco) and have great results. Even use less nutrients because it increases the uptake of nutrients.
I like it.


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RE: Compost tea as a hydroponic nutrient

My concern with compost tea in hydro solutions, especially if one adds molasses, is the possibility of e. coli. It's not common but it is not unheard of either. I did not feel it was worth the risk.

Mike


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RE: Compost tea as a hydroponic nutrient

Mike,

Could you expand on that? I don't think I have heard of anyone getting e. coli from compost tea. I have heard of a high risk when using manure tea. Particularly from corn fed cattle. That is what is so often used in organic farming, but somehow the word organics is confused with the word safe. I'm not saying you're wrong. Just wondering if you could point us to a resource that supports it as being a risk. Unfortunately, the term "compost tea" is used to describe a very wide range of concoctions. It could be composted manure, worm castings (whether vermi-T or your own worm bins), backyard compost from yard clippings, etc. and all of them fall under "compost tea" if you let it steep in water for a bit. Some is aerated. Some isn't and is allowed to go anaerobic. So I guess my point is that it seems to me that people definitely shouldn't base their course of action off a general term, but should first work out the little things like what is in the compost in the first place and how composted/aged it is.

I'm normally big on compost teas for the ground garden. Particularly worm cast teas. However, this year the only plants I have that have diseases are the ones I sprayed with teas I made from my outdoor compost mixed with some castings from my worm bins. I don't know if a disease was laying in wait in the compost or if it is complete coincidence. I am definitely a well seasoned composter and know what I am doing. I make sure the heat climbs significantly (160F+) for a period of at least 2 weeks and I let it "cure". Especially if I am going to use it for tea. It was good compost. All I know is, it didn't do squat for keeping disease at bay this year.


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RE: Compost tea as a hydroponic nutrient

Here is one article. It talks about hygiene being extremely important.

This is an extract from another article:
In contrast, use of commercially formulated mixtures or combinations of individual nutrient supplements consistently resulted in growth of pathogens and indicators in aerated CT. At 24-36 h, E. coli O157:H7 in CT increased 10- to 1000-fold and S. enteriditis increased 10- to 10,000-fold.

In fairness, I need to point out that if no e.coli are present in the compost, the chances of it being in the tea are not likely. However, that means the compost has to reach temps between 135-170 degrees for 15 days which will destroy pathogens.

HTH,

Mike


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RE: Compost tea as a hydroponic nutrient

I agree with the problem of using general terms like "compost" or compost tea and the fact that there is often confusion of what is actually meant.

The older the compost the better, simply because beneficial (and in fact harmless) bacteria remain in the compost and get dominant over time. This is just a natural phenomena. So don't ever confuse "quick-fire" compost with any compost that has matured for one or two years+. The more decomposed it is, the more nutrients and trace elements are readily available as well, obviously. If they aren't leached out due to exposure or porous underground, of course.

If using molasses, you have to understand that this is some kind of fast food for bacteria and yeast to multiply rapidly and thus accelerate fermentation. But if you feed in such way, you may multiply unwanted bacteria or yeast as well. That is why the inoculation with EM (effective micro-organism) comes handy here. They tend to become dominant quickly and keep your aero- or anaerobic fermentation clean, - in the same way as a clean yeast in vine fermentation. As soon as the selected fermenting yeast has multiplied and got started, your brew is almost safe from intrusion of unwanted organisms. Also, it's always better to allow to molasses to be completely fermented and transformed, before using any such compost especially in hydroponics.

Compost making and using teas in hydroponics is some kind of new science and there are specific techniques, rules and specs you have to learn and consider here. Here also you have got various and special techniques and it is recommend to go by the book of these, if you have no experience or don't know at all what you are doing.
In basics of aquaponics, you use more like fresh or less fermented manure, composts etc. instead but there you have to use appropriate growing beds that allow good recirculation, aeration and an ideal underground and environment for CONTINUOUS bacterial decomposition.

Seems to me that in any field, there are always people who want to imagine and do things their own ways, no matter how or what they are told by experienced people and experts. But as a consequence, so many people don't actually know what they're doing but obstinately follow their own bloody-mindedness instead. And sub consequently will be disappointed of the results or even screw it up in some way or the other. ;-)


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RE: Compost tea as a hydroponic nutrient

Can beneficials (bacteria, nematoads, fungi) be kept alive in a separate tank if supplied with aeration, water, molasses, kelp, compost, worm castings, etc. once TDS/EC levels max out? Can they be kept alive forever this way?

Can the aforementioned solution circulate through a hydroponic system without causing damage to the system if the compost tea is held in a small pore micron-screen bag?

Will the aforementioned solution be too varying in its nutrient/bacteria content and pH? Any way to stabilize it?

Hope someone out there knows the answers (and responds :D).


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RE: Compost tea as a hydroponic nutrient

Beneficial bacteria as EM can not only be kept alive, they actually multiply and bread if you feed them with what they need (molasses actually is the food and fuel for this). In fact it's not about keeping them alive, as they have a limited live span - but to keep them breading.

If using compost tea as main nutrient, or as supplement, it is recommended to simply using an adequate system where nothing can clog or get damaged. An Ebb-Flow system with robust in- and outlets is probably the easiest and most appropriate solution. Other systems may need filtering. Any Aeroponic system with fine spray or mist does not qualify. Unless you solve the problem with adequate filtering which still filters organic micro particles (perhaps beneficial bacteria) out - and your tea will not decompose any further any soon. Look how Aquaponists deal with it and how it is solved in this filed. You can learn a lot from them.

The most simple solution to have consistency with the nutrient content or concentration is probably to firstly work out your own "recipe" with a series of empirical tests to determine an optimal brew that delivers what your plants need. Example: you use X Kilo or Pound with a composition of 20% compost A plus 30% of compost B, add 10% of seaweed extract, 5% of bat guano, 5% molasses, plus percentage of other ingredients, etc. You inoculate the MIX with x milliliter EM or bacteria and brew the whole enchilada with 50 Liter /gallons) water for X days. Once your recipe is modified until working, you simply repeat the process with equal parts and the same variables and you will end up with almost consistent results every time. If you have access to such recipes, you can use or try those of course - or use them as a guideline.

You can also use EC measuring, knowing that there will be quite more Nitrogen and other elements that aren't water soluble, dissolved or decomposed yet. Here you simply use the EC as an INDICATOR with your tests and experiments.

With pH regulation, consider that depending on setups like Ebb/flow (plus a massive growing area filled with media) you deal more with a "soil-like" environment, where plants are able to regulate root zone pH to a (hopefully) sufficient level by themselves.

Hope this helps and is useful.
Cheers,
Lucas


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RE: Compost tea as a hydroponic nutrient

Lucas and others willing to share experience,
I have been doing some research attempting to get some answers concerning the following and have been getting mixed answers and would like to get your opinion.
I would I be able to keep beneficial bacteria and mycorrhizae alive in my system but have read some places that the synthetic fertilizers won't keep bacteria/mycorrhizae alive (no food for them, need organics), while others say it will as long as they are established first since they will ultimately be feeding on dead roots/etc.
I was wondering if I used synthetic fertilizers for nutrition, but added a small amount of compost tea as a supplement to my nutrient reservoir would it help keep beneficials alive and replicating?
My tea contains bat guano, seabird guano, seaweed extract, worm castings and molasses. I am going to be growing in perlite and would inoculate with a powdered mycorrhizae.
Basically I am not trying to use the tea as a nutrient (yet), just trying to help keep the benificials alive while using synthetic fertilizers.
Thanks for your help!


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RE: Compost tea as a hydroponic nutrient

@sdgrower
Interesting and also a bit difficult topic. Little research about various hydroponic applications available as well. But basically mycorrhizae, various beneficial fungi and other microorganisms will have a direct interaction (a so called mutualistic or symbiotic relationship) DIRECTLY with plants and will have access to carbohydrates directly from them. The term "synthetic fertilizers" isn't exactly appropriate either from my understanding and especially in this context it may lead to misconception. There is no difference between bacterially decomposed N-molecules and the ones that are provided by salts used in hydroponic nutrients. On a molecular level it's not exactly the same, as some processes are bypassed. But what plants actually do absorb happens on an elemental level and they can't tell the difference between N and N, or K and K as there is any between elements provided by microorganisms and the ones provided by salts. Besides, plants simply can't absorb any organic substances or components but only in water dissolved ions and related.

If we use chelated micro nutrients for example, those can be called "synthetic" in fact, because we deal with a combination of organic and inorganic components that result in a substance with "new" properties (a synthesis). However, any nutrient solution based on salts and commonly used chemical components isn't a microorganism unfriendly environment at all. On the contrary, it's more like a perfect imitation of dissolved soil in water with very similar chemical properties and pH.

But then again mixing both, organic components and directly available and pure nutrients (based on chemical components), isn't exactly a good idea, because you mix a known and given with a unknown and 'convertible'. Generally it's dis-recommend to mix up both, because of unpredictable pH fluctuations and danger of contamination. But that's more of a standard reply. PH can be controlled and corrected - nutrients could even be adopted to fit specific organic components as part of the solution. And Inoculation isn't a contamination, but in fact an antidote. Thus, mixing both (only) adds one more degree of difficulty with control and reliability.

There is a simple solution to most complicated problems, and in this case it would be threefold:
1. keep your nutrient solution clean and almost free from organic components, inoculate only and/or use foliar spray with beneficial fungi, EM, other bacteria, amino acids, chitin, etc...

2. Go for organic (why do I hate that term?), use an appropriate setup, sufficient media (semi- or fully organic). Experiment based on what you have researched and thus seems safe enough - and let nature play it while you observe and learn.

3. If for some reason you still want to mix or combine both, consider it experimental with a capital "E" and do not confuse it with a sure to grow, safe and/or hassle free production method.

Cheers,
Lucas


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RE: Compost tea as a hydroponic nutrient

Thanks Lucas, very helpful!

I am going to stick with number 1 for now since that has worked well for me in the past, but I am going to do some research on inoculation practices and foliar applications and move forward with those techniques.

Your point about the compost tea having both beneficial and contaminates while the inoculations contain only the beneficial makes sense to me and I will take your advice.

It is interesting that the potential contamination problems using the tea as a nutrient are not an concern when used as a foliar spray. I am going to look through the archives and find some more info, thanks for the lead.
-Lots to learn!


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RE: Compost tea as a hydroponic nutrient

You're welcome sdgrower,

In the same way as the term "synthetic" may be misunderstood, contamination or "contaminants" can be as well. A contaminant is simply and per definition an impurity, a foreign matter. In some context ( with food- or soil contaminant) it mostly is something negative and certainly unwanted. But in some other context it's not necessarily or exclusively negative. Some commonly used salts for nutrient making contain some Fe and Mo (some Co or Ni, even Al or a few ppm of Pb) as contaminants, but except Pb, they are in fact welcome in a nutrient solution. Btw: In soil we have them as well and unfortunately for some, (often) in higher amounts as in chemical components.

The role any "contaminants" of organic matter may play in a nutrient solution, is in fact related to the predictable and given part I was talking about earlier. They are not necessarily or exclusively a bad thing either - but simply change the rules. As soon as we introduce a certain amount of organic matter in a nutrient solution, we waive the privilege of control we formerly had with salts only ... ;-)

Concerning the bacterial part, the purpose of inoculation is in fact to introduce a dominant bacteria or fungus, that controls others - a bit like the role of yeast in Wine making. In this context we do not care about a "contamination" with other bacteria or fungi, but actually relay on the inoculation with beneficial and dominant species which are supposed to dominate the environment.

You also have to differentiate like follows: some additives and beneficial elements can be introduced or used directly in a nutrient solution (without affecting the rules), while others are better used as a foliar spray only. Folic acid (potassium humate), chitosan and amino acids (more recently used amino acid chelates) can be used and introduced directly to the nutrient solution or sprayed. While any more voluminous organic matter or liquids, compost tea, Effective Microorganisms (any EM derivates) and Trichoderma harzianum, are more effective and safe as foliar sprays. Most of them can also be used as a root treatment (dropping in a solution when transplanting) or even as a seed treatment. Also, some treatments are onetime only, (Trichoderma harzianum inoculation for example) while others shall be repeated frequently (like EM).


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RE: Compost tea as a hydroponic nutrient

One more addition (actually a correction):
When I said earlier that plant's can't absorb any organic matter it is only partially true and mainly concerns non-decomposed nutrients as NPK-Ca-Mg-S, etc in organic matter. Nevertheless, roots are still able to absorb several biotic and other organic substances, as amino acids, vitamins and even antibiotics. Also the presence of bacteria versus a "sterile" nutrient solution is determinant (interactive) for the uptake of some of these organic substances.

Thus "sterility", versus inoculation and the presence of bacteria in a nutrient solution remains a disputed and rather uncharted territory.


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RE: Compost tea as a hydroponic nutrient

Lucas,
All this info is great! I am unfamiliar with Folic, chitosan and amino acids as foliar sprays and will do some research on those next.
As far as root inoculation goes… Do you recommend using powdered inoculants vs. liquid?
From my understanding the powdered/dry forms are more likely to have biologically active organisms, while the liquids may have reduced life due to cold/heat/ long time on shelf… seems to make sense?
Many of the commercial available “Rooters Mycorrhizae” products and other “Root Growth” products state the product should be used as a an inoculation during transplanting, but can also be mixed into the nutrient solution every week or two. If I understand you correctly, you feel the inoculation during transplanting is ok, but to be cautious of adding into the nutrient on a regular interval? (Howard Resh also recommends just inoculation with Trichoderma harzianum, strain T-22, but only at transplanting)
I understand the manufacturers are trying to sell more product, hence their advice on using regularly; can you elaborate a little more why you feel they should only be used once (not questioning your methodology, just trying to understand a little more)?
Am I confusing “inoculation” with “adding to the reservoir”? Is it practice to re-inoculate each plant by pouring a little water + Rooters Mycorrhize directly onto the plant site periodically instead of adding to the reservoir?
Thanks again for all this I apologize for the lack of knowledge on the subject, I have done lots of looking on the net and reading books, but this topic is a tough one as you mentioned multiple times. Definitely going to play it safe with the additives, but also want to start experimenting.
Hopefully someday I will have some little nugget of worthy information to share back with you and the rest of the forum!


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RE: Compost tea as a hydroponic nutrient

sdgrower,
Well, again it depends on the properties of different substances and organisms. As for Trichoderma harzianum, only a single inoculation is needed to have it assimilated and "installed and resident" in plants. Thus no need to repeat the process and no need to "contaminate" the Nutrient solution either. The recommendation of Dr. Resh is hence correct and to be understood purely pragmatical. The same is basically true for mycorrhizal, once inoculated, they are supposed to be installed.

Humates (postassium humate) or Amino Acids, are more like actual and permanent additives, as they are being assimilated continuously as part of a plant's diet.

Chitosan again is some sort of "active substance" and besides its main effect as a "natural growth enhancer" it's supposed to have antifungal properties and eliminate toxins. It can be sprayed or added on a regular basis.

Effective Microorganisms, sometimes contested to not actually being "that effective" need to be grown and multiplied in a starch/molasses mix which isn't the best thing to add to a nutrient solution. But as a frequent use is recommended, frequent spraying is the best option here.

Trichoderma harzianum is best directly as a fungal culture (on corn) and for all others I use the powdered form and dissolve them in water. Chitosan powder (concentrate) needs to be dissolved in highly concentrated acetic acid first, though. Effective Microorganisms generally come in liquid form (concentrate) and seem stable that way.

PS: don't worry about the (temporary) lack of knowledge, some of it is rather new to me as well. Also, the actual knowledge is somehow linked to availability of products. Example: I was using Chitosan in liquid form until recently - and the recipe and instructions of making your own liquid concentrate only came with the powder... until then I didn't even know of it. ;-)


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RE: Compost tea as a hydroponic nutrient

To begin with, the whole process of watering and fertilizing your garden (hydroponic or other) is made to appear overcomplicated to the extreme. There is a very simple solution which I have been using successfully for the past year in all my gardening systems, hydroponic, container & ground with excellent results. It is called Worm Tea and is very simple and cheap and abundant to make and requires no added ingredients other than your household and garden waste processed through your worm bin daily. In the following paragraphs you will find instructions.

I really don􀳦t see the need to harvest worm castings or "brew"
worm tea from castings at all. To me it seems like unnecessary waiting, unnecessary
energy spent and actually less efficient use of the worm "offal". In the following, I detail
a much simpler method which I think is more efficient in every aspect, and I would like
to know what you and your audience think. Using this method, my garden has grown
quickly without the use of any other fertilizer and severe infestations with aphids and
white flies have disappeared. I also would like to know what you recommend as a
mineral, etc. supplement to worm tea, or is it a complete fertilizer in itself.
I built a worm bin in a 25 gal Rubbermaid Tote, Drill 1/4" holes in the sides of the container 6" up from the base and also in the lid but not in the bottom of the bin. Then I installed a PVC drain valve in one end near
the base of the unit. Next I put a bag of gravel over the drain valve intake, filled with
bedding, kitchen waste and worms and wait 2 or 3 days for the worms to do their thing.
I pour a 2 gallon watering can of water over the worm bin contents 2 or 3 times daily
and put the can under the spigot and turn on to allow it to drain into the can.
PRESTO, worm tea and it works very well. This Worm Tea (or Leachate, call it what
you will) is simply the dilute and FRESH version of Worm Castings and can be poured
directly over the leaves of your plants and/or onto the soil of your garden.
This method avoids the 3 to 6 month waiting period during which time your worm bin
matures after which the castings can be harvested. This way your worm tea can be
harvested almost immediately and several times per day providing up to 6 gallons per
day of effective, perfectly diluted worm tea for your garden. Using this large volume of
water and not allowing it to sit in the worm bin avoids the problems I have seen others
have of making the worms uncomfortable, etc. My worms have yet to "run" and are
never to be found crawling on the sides or lid of the worm bin, and just appear to be
very content to take their daily "worm shower".
It appears that what is happening is that the water is partially dissolving the worm
castings and cleaning out what other worm wastes are present (pee, poo, sweat,
slime, etc.) and keeping your worm bin clean and attractive to the worms. In other
words, they don􀳦t have to crawl around in their own waste products for several weeks
or months. Since their home stays nice and clean with plent of aeration and food, they
have no reason to leave. It just works, plain and simple, with the absolute simplest and
cheapest design, least amount of labor and attentiveness and greatest productivity of
any system I have heard of. Try it, you􀳦ll see.
Michael
RE:


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RE: Compost tea as a hydroponic nutrient

A member, tengreenthumbs, used to insist on using compost tea to grow hydroponic tomatoes but eventually gave up because there wasn't enough nutrient in the tea to support a full grown blooming tomato plant. for house plants, herbs, and the like, it'll probably be fine. but for anything that requires substantial nutrients you'll find, as he did, that compost teas just aren't strong enough.


 o
RE: Compost tea as a hydroponic nutrient

I have done some of my own experiments using aerated vermicompost tea and here was my setup:

7 gallon square pots with mesh bottom
Storage tote
Flat disk air stone
250 watt CFL lamp with reflector

Vermicompost
Kelp
Alfalfa
Sterilized chicken manure

Using this equipment, I created an organic bubbleponics system to grow Korean pepper plants. My understanding is that vermicompost is great for plants not for the nutrients contained within it, but rather the beneficial microbes from the earthworm gut that are inoculated on the digested material. These microbes work in a way similar to the ammonia-nitrite-nitrate bacteria in an aquarium system that allow unusable forms of nutrients to be converted into plant usable forms. This is why I included the various organic fertilizers for the microbes to convert. I didn't have any problems with bacteria or microbes clogging the system since it was essentially a bubbling DWC system, but even as such, there was no films or strange brown slime to speak of.

Anyways, on to the results! I had never grown this pepper before, but even though I paid very little attention to these plants, they managed to bloom and produce peppers (about 8-12 hellishly hot offspring) although the plants were admitedly small (1 foot). Furthermore, I experienced quite a bit of a whitefly problem, although the plant managed to tough it out and complete fruiting, unlike its jalapeno bretheren which were eaten alive by the same pest.

This experiment proved to me that organic hydroponics can definitely work, but the comparative efficiency of it to traditional hydroponic methods is still up in the air. I might start a new experimental testbed to compare this organic hydroponic setup to a commercially available hydroponic nutrient solution.

P.S. I have also grown tomatoes (albeit small) using a seaweed extract and fish poo system, so it does work, but just not very well.


 o
RE: Compost tea as a hydroponic nutrient

Seeing as a filter is common sense anyways, why not supplement with compost tea filtered though a sand bio filter to filter out potential pathogens?

I'm thinking this: Take the some fairly good digested compost and place it in a nylon stockings drain some water through it, and catch that which runs out and add it to your nutrient solution at the top a sand bio filter. Sand bio filtering is done though pumping water to the top of say a 50 gallon drum with large rocks at the bottom followed by progressively smaller rocks with 2 feet of sand and topped with some cloth or other suitable material to prevent disturbing the top layer of sand. Oxygen may be introduced by letting water from the inlet splash on top. The nutrient solution will trickles down through the sand filtering out both pathogens and "undigested" particles. The top layers of sand serve as a bio filter where beneficial bacteria grow and further digest undigested particles.

Another thing, If one were off in nutrient solution concentration would it be safer to be a little rich or a little lean.


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