# Recycling of fertilizers



## zem (Nov 25, 2013)

I have been looking around for some information concerning the recycling of fertilizers. I know that growers change the res in small scale ops but i have heard of lettuce farms who keep the fertilizers indefinitely. i can avoid the use of sulfates and chlorides and use RO filters to keep useless salts from building up to toxic levels. I can right now feed plants chemicals which they will use up entirely, but is that enough? Because I have heard that plants themselves release chemicals into the water, is that true? if so, how is it recycled? i can in fact use a tester for every element in the water like nitrate tester, phosphate, potassium, calcium, magnesium, iron, etc... each can be tested alone and then TDS test to know the useless salts' concentration. this of course is not for small ops, and is not for marijuana farming, i am in the process of studying a project to grow hydro veggies, and i have a very busy test greenhouse on my roof. Anyone knows where i can get info on commercial hydro methods?


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## The Hemp Goddess (Nov 25, 2013)

Recycling of fertilizers?  I don't really understand what you are asking.  Are you talking about just topping the res's up instead of completely changing out the res?

If you run the nute solution through an RO, it will take the nutes out of the water--it removes all the dissolved solids. the good with the bad.


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## 4u2sm0ke (Nov 25, 2013)

A bit confused here too

:stoned:....How does one recycle Nutes when in water?


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## Growdude (Nov 25, 2013)

I completed a entire grow without changing the rez.
Results were ok but not my best.

But if you have the capability to test for each element then its would be easy to maintain your nute balance.
I don't know if any thing is put back in the nutes by the plants, if there were I really didn't notice.


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## zem (Nov 26, 2013)

Growdude said:
			
		

> I completed a entire grow without changing the rez.
> Results were ok but not my best.
> 
> But if you have the capability to test for each element then its would be easy to maintain your nute balance.
> I don't know if any thing is put back in the nutes by the plants, if there were I really didn't notice.


yes I can test each element in water. the result of my study shows that plants don't use up sulfates and chlorides as well as some chelating agents, so they can build up to toxic levels as you top the res. I can avoid sulfates and chlorides and keep them under control. I too have finished OK grows with one res, BUT not my best. right now, I have grape tomatoes growing huge in a greenhouse. they have been on the same res for 2 months now. Problem I am encountering is that they need calcium but no more Nitrates, and I only have Calcium nitrate as calcium supplement, so even at ppm 800-900, I think that plants are experiencing some Nitrogen overdose, I notice dark green and somewhat clawing leaves. High N low calcium prevents grape tomato flowers to form a knot and produce a head...
When I say "recycle" I mean they just top and grow a new run in the same fertilizers. Huge lettuce farms that use floating raft systems have massive ponds which they don't dump out ever. I am researching about that intensively now, I have a plan to begin a greenhouse commercial operation by June-August, and I need more sophisticated techniques for reservoir management


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## Sin inc (Nov 26, 2013)

thats very interesting . can you post your finding


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## trillions of atoms (Nov 26, 2013)

I run rez addback and cut my nute usage like crazy. So much that im afraid my jugs will be to old by the time I finish several runs.


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## Growdude (Nov 26, 2013)

zem said:
			
		

> yes I can test each element in water.


 
What type equipment is needed for this?
I would love to be able to do this.


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## zem (Nov 26, 2013)

it requires quite a wide range of testing equipment. testers for nitrate, phosphate potassium, calcium magnesium, iron, chloride, dissolved oxygen and what else... I don't think a small scale farm is going to use this method, but for big scale ops, it is very economical. you can find the equipment in such places like : hXXp://www.eseasongear.com/wateranalyses.html
hXXp://www.hannainst.com/usa/prods2.cfm?id=009001&ProdCode=HI%2096750


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## WeedHopper (Nov 26, 2013)

I used to pour my old solution on my Outside plants,, when I changed out my rez. They seem to like it just fine.


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## The Hemp Goddess (Nov 26, 2013)

I do like Weedhopper--my flowers just love left over nutrient solution.

This seems like an incredible amount of work and complicated.  First you have to measure about a dozen different elements.  Then you need each of these separate elements in a form that can be used in hydro.  And then you have to add it back in the correct proportions.  And then you get to adjust the pH.  It would seem also that nutrient imbalances would need to be addressed...like if the plants were using a larger amount of one  nutrient and little of another.  For if the system stayed "even" there would be no problem with topping up.  But that is usually not the case.  It just seems quite complex.    

You also mentioned running the solution through an RO to remove the salts.  However, wouldn't running the solution through an RO also remove the beneficial nutrients that you are trying to keep?


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## WeedHopper (Nov 26, 2013)

I know my Zero Water Filter removes even the color.You can almost make Water out of Wine.LOL
My City water TDS is about 200,,the Zero filter makes it just that Zero TDS for several runs. I throw it away when my Filtered water reaches 100.Which is stii much better the the Tap at 200.They say replace at 6 tds,,LOL,,yeah,,that aint gonna happen.


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## zem (Nov 26, 2013)

The Hemp Goddess said:
			
		

> I do like Weedhopper--my flowers just love left over nutrient solution.
> 
> This seems like an incredible amount of work and complicated.  First you have to measure about a dozen different elements.  Then you need each of these separate elements in a form that can be used in hydro.  And then you have to add it back in the correct proportions.  And then you get to adjust the pH.  It would seem also that nutrient imbalances would need to be addressed...like if the plants were using a larger amount of one  nutrient and little of another.  For if the system stayed "even" there would be no problem with topping up.  But that is usually not the case.  It just seems quite complex.
> 
> You also mentioned running the solution through an RO to remove the salts.  However, wouldn't running the solution through an RO also remove the beneficial nutrients that you are trying to keep?


yes it is complex but for large scale grows, dumping huge reservoirs is costly and preserving your nutes is worthwhile. I mentioned RO filters that is for the original water source not for the fert mix


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## The Hemp Goddess (Nov 27, 2013)

Zem, this is from your initial post:  " i can avoid the use of sulfates and chlorides and *use RO filters to keep useless salts from building up to toxic levels*."   Since you apparently weren't talking about running the solution through an RO like it sounded, how do you plan on dealing with salt build-up? 

Can you go through the process that this entails.  How have you determined the correct level of all those separate and different elements? What is your source for replacement nutes?  How do you compensate if you are deficient in some elements and have high levels with others.


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## zem (Nov 27, 2013)

The Hemp Goddess said:
			
		

> Zem, this is from your initial post:  " i can avoid the use of sulfates and chlorides and *use RO filters to keep useless salts from building up to toxic levels*."   Since you apparently weren't talking about running the solution through an RO like it sounded, how do you plan on dealing with salt build-up?
> 
> Can you go through the process that this entails.  How have you determined the correct level of all those separate and different elements? What is your source for replacement nutes?  How do you compensate if you are deficient in some elements and have high levels with others.


I can determine the correct ppm of every element for every plant first by looking it up through research then by doing a test run. it is normally a range in which plants thrive. In different fertilizer formulas that were based on studies, I could find lots of good info. 
The fertilizers are raw chemicals in parts. For example, I use Calcium nitrate, potassium nitrate, monopotassium phosphate, magnesium sulfate and trace element mix. If I want to add more nitrogen only, I could use amonium nitrate, calcium phosphate or triple superphosphate for Ca and phosphate, Magnesium Nitrate for Mg without sulfates, and so on. There is a wide range of chemicals which one might use for different crops, and for big farms, even trace elements like Boron Iron and zinc are bought in parts like Boric acid. it saves a lot in fertilizer bills and gives the farmers perfect control. Up till now i am still working with the 5 parts I mentioned, add to it phosphoric acid and H2O2 35% food grade. results are great, if I am to do professional greenhousing, I need to have a good working system for fertilizing/recycling. I am leaning towards a floating raft lettuce and herb farm, then maybe adding a wider variety as a second step in artificial medium, crops like tomatoes and cucumbers...


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## The Hemp Goddess (Nov 27, 2013)

Thanks for the explanation zem.  It sounds like a really interesting research.


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## zem (Dec 3, 2013)

2 days ago I checked the ppm and it read 580 which pleased me since the plants are feeding well, so I raised the ppm back up to the 1100 level. Yesterday, the res was about 1/4 empty, so I topped it with 240ppm tap water, to my surprise, I checked today and ppm jumped UP to 1400 instead of going down, which brings up the question related to this thread: wher is the extra ppm coming from? if plants are releasing something into the water, what would it be? thanks


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## pcduck (Dec 3, 2013)

ppm's are just getting concentrated from the plants just drinking water


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## zem (Dec 3, 2013)

pcduck said:
			
		

> ppm's are just getting concentrated from the plants just drinking water


but, I topped 1/3 of my res with 240ppm, when my res was 1100ppm, how'd it go to 1400?


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## pcduck (Dec 3, 2013)

they up-taked just the water with no nutes, they did not feed they just drank the water.

This would remove the h2o while concentrating the nutes


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## WeedHopper (Dec 3, 2013)

1100ppm+240ppm= 1340ppm


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