I use your idea on a much reduced scale. I use my fishtank water - which contain small amounts of nitrates, phosphates and calcium - as a supplement to my hydroponic nutrient solutions.
Been doing this for years.

That's an interesting idea.

To grow in hydro really successfully, the plants need all these essential nutrients. They also need macronutrients.

Essential Nutrients
Nitrogen (N),Phosphorus (P), Potassium (K), Sulfur (S), Calcium (Ca) & Magnesium (Mg

Micronutrients
Boron (B), copper (Cu), cobalt (Co), iron (Fe) manganese (Mn), molybdenum (Mo), and zinc (Zn)

I don't think your waste would suffice for hydro, it's not going to have the full range of these chemicals. It would probably be fine if you were a 'dirt' gardener though, as fertilizer.

That said, why not give it a go?

well it should have all that stuff also, but first i need to be able to capture the water i want to use and have a sample of it tested course thats going to be the major problem is coming up with about 20 thousand right now to buy and install the storage tank, which i need to do reguardless weather this venture will pan out, which i need to meet the state regulations

Many of us brew our own nutrients, myself included.

I think you're going to find using straight cow manure will be too high in nitrogen for starters.

It would be better if you anaerobically digested it first. That means it has to "rot" where there is NO oxygen. Once it's digested, it should be fine for hydro nutrient.

The only way you'll know for sure is to try it out first hand. If you have time constraints, just buy some anaerobically-digested manure and use that.

Be sure to measure the EC and pH of your brew before trying to feed it to any plants. Each plant grows within a certain "range" of EC and pH.

I've included a link to my Web page, where EC and pH are explained in more detail.

Here is a link that might be useful: EC Discussion

The anaerobic digestion will convert ammonia into nitrogen, which will be lost as a nutrient. I think an aerobic digestion would be more efficient. That will convert most nitrogen sources into soluble nitrates, and the residue will be plain pulp.

Anaerobic / aerobic -- I've tried both; anerobically-digested manure is what I use full time. I make "tea" from it and you've never seen greener plants in all your life!

I'm pretty sure that's from nitrogen, eh?

Have you ever had that tea tested for nutrients?

well being a dairy farmer i'm no stranger to cow manure and i've gone out in our front lot which has a mix of old and new manure with dirt looks almost like black top soil and watch out it grows flowers and plants i think better then mericial grow. as for the manure itll be in a storage tank for roughly 7 days, and as i said i would have to tested through the same place we have our fields soil tested.as for that "tea" thats what im looking at from this but the solids would be removed with screening and such. I just haven't seen much or heard much about anyone using wastewater/animal sewage for the hydroponics so far what i've read people just buy a solution already made up. which to me looses some cost savings. I really wont know how labor intensive this will be i am hoping to do it year around. but right now i'm In researching mode. and i appreciate all you folks can give me on this. ive also tought of not going with a glass greenhouse case of the weather and where this will be located, i fear it'll get damaged more often being glass then some other form of translucent material.

You could probably just compost it like the others have been saying and package it up for sale at the local nursery. Compost will sell to a larger audience than just hydro growers.

oh the waste water is for my own 134 acres and hydro part but yeah ive talked about also taking our front lot and piling it up about a foot deep thats about a 1/4 of an acre worth and selling it t people who come by as nice topsoil/compost. course then we get into the stupid township laws of moving more then 500 yards of dirt and what not which is stupid, but yeah i could probably do it also i just need more hired hands..

If you're worried about damage to your greenhouse, there are several companies that manufacture polycarbonate sheets for building greenhouses. That stuff is bullet-proof!

Along those lines, Harbor Freight sells a polycarbonate greenhouse for around $700. A local grower friend of mine picked up a used one from Craigslist for around $200!

As far as selling cow poo for compost, you'll attract a greater customer list if you pile it up and let it sit like that for about a year.

The piles will naturally digest and will even smoke from the heat the digestion produces. That's okay; it's supposed to. Just pile it up and leave it alone to "season" for a year. After the time passes, the size of the pile will be greatly reduced, but the contents will be more salable than the fresh stuff.

This will probably work for a hydroponic crop with the addition of some iron (which is the main nutrient that sewage water would lack), proper sterilization is also needed to eliminate any bacteria or fungal spores that might be present within it. I would recommend a process of UV sterilization, followed by pH balancing and iron addition. It should work, there is some research on the matter.

Here is a link that might be useful: Everything about Hydroponics

Greystoke: RE -- "Have you ever had that tea tested for nutrients?"

No. I'm one of those trial-by-fire kind of guys. I just tried it and it seems to grow everything I want to grow just fine.

I do from time to time add a little magnesium sulphate (Epsom Salts) to adjust my EC when things are in fruit and I don't want extra nitrogen. My water has so much calcium in it raw, I don't need to worry about that mineral; you can almost walk on my water without being holy!

By the way, I grow strawberries, tomatoes and potatoes 100% hydroponically. The only dirt in my garden is what gets tracked into my greenhouse on my boots!

freemangreens RE
As far as selling cow poo for compost, you'll attract a greater customer list if you pile it up and let it sit like that for about a year.

The piles will naturally digest and will even smoke from the heat the digestion produces. That's okay; it's supposed to. Just pile it up and leave it alone to "season" for a year. After the time passes, the size of the pile will be greatly reduced, but the contents will be more salable than the fresh stuff.
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umm yes i am a farmer have been 1 all my life i understand the nature of the "poop" as people would call it, I understand that it will compost and what fresh stuff will do(burn plants) and yes this stuff has been sifted around for over 20 years so theres a lot of old mixed with a very slight bit of new and as for the comment on the steam and such yes i know that also they even have gone as far in the dairy management to take your dead cattle and bury them in a manure compost to get rid of it in that form, though i do not do that cause of a few reasons 1 if there is some bio hazard with the animal itself 2 i wouldnt want to have that sold to any person if they happen to come by to get some, so I have someone come take them away for reclimation, which cost me a fair amount for 1 animal, it would be cheaper to do it the other way i just dont. ive used this stuff myself and have had no problems with it being too toxic to grow anything in. but i'am not here for that i was here more for what i was doing with hydroponics.

An update is im looking to build a 32' by about 16' wide and about 16 foot the peak which would give me a 12' over head for a bobcat to come in the door if need be. I would like to use this year around if possible thinking of a radiant heated floor in it and use polycarbonate sheets for it. question is can i make one that size with a clear span or ive thought of wood style structure but with the moister i think id be having issues.