# Urea as fertilizers for aquatic plants?



## Formzero

hi guys, my grandmother uses urea on her plants as fertilizers. is there somehow can be used in planted tanks? ive read the wiki and it says Urea is widely used in fertilizers as a convenient source of nitrogen and it is highly soluble in water and non-toxic. dissolved in water it is neither acidic nor alkaline. has anyone tried this? if its non-toxic so it wont harm fishes right?


----------



## HeyPK

Urea can be used as a nitrogen fertilizer, but, same as an ammonia containing fertilizer, it can not be given in large doses without danger of harming fish and invertebrates. I have never tried it with fish, but I had an experience where too much urea killed Daphnia.


----------



## Formzero

thanks for the quick reply pk, is there a way we could eliminate ammonia? or let's say should i try this on a fishless planted tank and clear out ammonia before inhabiting the fishes?


----------



## HeyPK

If the tank has a moderate to heavy amount of plants, they will take up the urea or ammonia quite quickly. Otherwise, one has to experiment. Add small doses. Do the fish and inverts seem healthy? then carefully increase the dose. Don't double it; increase by 1.5X and watch carefully. I have not experimented to see how much urea I can get away with. It may turn out that fish and inverts are more tolerant of urea than of ammonia as in, for example, ammonium nitrate. All I know is that there can be too much urea. Urea has the following formula:


NH2
|
C=O
|
NH2


I have read that plants can take up the entire molecule, meaning that it does not have to be broken down outside of the plant before the nitrogen can be absorbed. 


Nitrate is much safer, and is a good source of nitrogen for plants. Fish are much more tolerant of it. Research has shown that ammonia is taken up by plants much faster than nitrate. However, nitrate is taken up rapidly enough by plants so that they don't become nitrogen limited even if the nitrate levels are low, in the order of one or two parts per million.


----------



## ray-the-pilot

Urea will decompose by itself and the rate of decomposition is increased by some microorganism. The result is ammonia and CO2.

H2NCONH2 + H2O --> 2H3N + CO2
My feeling is that there is some risk in using urea as a nitrogen source. But it would be interesting to see what your experiments show. 
Try to keep careful records of how much urea you add to your tank and report back with you tank statistics and how you are doing. Especially report if you have a fish kill as this is an important results.
If you can keep your tank going for a few months, you will be paving new ground! Good luck!


----------



## Formzero

hi, thanks for the reply. i guess ill try out fishless tank first than risking all of my fishes, i have moved them to another tank and try to do some experiment on my 12gal tank about the urea. ill update this thread from time to time on how this fertilizer affects the inhabitants as well. ill be putting only one cheap fish as a lab rat to see if it can survive. thanks.


----------



## Formzero

Day 1

I just added 1tsp of Urea to a 30gal fishless planted tank. lights at 2x20w CFL @ 6500 with natural light coming from the window (but not direct hit to the tank. Co2 3bps (DIY). Substrate is a mineralized soil but with the absence of dolomite since i could find any. Ill update the results..hoping i could find a ratlab fish.


----------



## wet

Just bits from someone who dosed Calcium-Ammonium-Nitrate (CAN, 5Ca(NO3)2.NH4NO3.10H2O unless I've my hydrations misunderstood) into a plant-only aquarium but likely never will again:

1) Even if we take for granted that plants consume Ammonia/um more readily than Nitrate, how practical is this in the ornamental (plus-quality plants) aquarium when we can't keep fish?

If you're of the type who feels the plant uptake is so fast fish won't be affected, what if you're wrong? What of all the aquarists on APC who grow plus plants with KNO3, keep some fish, and never ever think about Urea and stuff?

2) plantbrain-reference: that guy thought about the advantages of Urea and figured he'd just bump his schools of tetras up for, say, 20 to 40, then feed regularly so he keeps fat, happy fishes. If we agree/assume that Urea does make a difference to plant growth, I've yet to hear a more elegant and fish-friendly solution to this problem.

(Assuming the tank is big enough for the school, etc. If it's not and near some margin for stocking/space/biowaste, adding Urea is a bad idea anyway.)

3) Be wary of terrestrial and agricultural fertilizers and their potential additives/whatevers for this type of thing. For example, here's pics of my Calcium-Ammonium-Nitrate. That's an oily film with bubbles floating on top. This would have been a marginal dose into ~20 gallons of water.



















Hoping this helps; far from discouraging you from trying for yourself. Just information.


----------



## Formzero

hi, thanks for the informative reply. would just like to explain some situations as follows.

1. yes, i was just observing by experience on how aquatic plants reacts to urea which is nitrogen based fertilizer and organic too. as for ammonia/oum, was aware it is toxic to faunas at large amounts. i know its not practical, but maybe at lesser dosage, it wont harm the fishes. and if im wrong, i learn by my mistakes.

2.i have read some articles in this forum and some they are using urea at a very low dosage. in my case, of curiosity i would like to try on my own knowing the risk.

3.how much have you induced the CAN, if you dont mind some details.

yes, i am very pleased on about your comments. this would serve as a challenge not for them but on my own experience. i wouldnt take it as a discouragement. thank you very much.


----------



## Formzero

Day 3

i dosed up 3 tsp of urea and increased the amount of Co2 rate to 5 Bps. i notice micro worms inside sticking the glass, around 0.2mm at length and a very tiny almost invisible to notice at a distance. i guess these worms came from the mineralized soil. lights wer on i added up 20watts fluorescent t12 in addition to 2x20CFL, all at 6500K. Plants starting to pearl and algae starting to minimize. more updates.

as i rechecked the tank, BBA started to appear while green hair algae starting to wear off those sticking to the plants.


----------



## ray-the-pilot

Formzero said:


> Day 3
> 
> i dosed up 3 tsp of urea and increased the amount of Co2 rate to 5 Bps. i notice micro worms inside sticking the glass, around 0.2mm at length and a very tiny almost invisible to notice at a distance. i guess these worms came from the mineralized soil. lights wer on i added up 20watts fluorescent t12 in addition to 2x20CFL, all at 6500K. Plants starting to pearl and algae starting to minimize. more updates.
> 
> as i rechecked the tank, BBA started to appear while green hair algae starting to wear off those sticking to the plants.


Do you have any fish in your tank? How are they doing?


----------



## Formzero

forgot to mention, got 1 guppy. as i dosed 1 tsp of urea seems to be doing fine. at increased rate seems stressed out and surface for oxygen. today i havent dosed any urea, seems back to normal. the worms i mentioned seems to grow around 1cm at length.


----------



## HeyPK

Now that you have dosed 4 tsp of urea in a 30 gallon tank, that should be enough nitrogen to support a considerable amount of growth. How are the plants responding?


----------



## Formzero

Day 4

the plants seems to do well on urea, i had to lower the dosage to maybe 2 tsp noticing stress to the guppy. green hair algae started to wear off.. worms are still present. i wonder where these came from, my greatest hunch is from the mineralized soil. BBA are still present too but tolerable.


----------



## ray-the-pilot

Formzero said:


> Day 4
> 
> the plants seems to do well on urea, i had to lower the dosage to maybe 2 tsp noticing stress to the guppy. green hair algae started to wear off.. worms are still present. i wonder where these came from, my greatest hunch is from the mineralized soil. BBA are still present too but tolerable.


I know that a beautiful tank is what you want to see but we need long term results. Can you keep up your plan for a few months and report back every week? A four day test is not very long?


----------



## redchigh

Also, the worms are probably planaria. You could use them as your lab rat animals... And save the poor little guppy.


----------



## Formzero

day 15

for the past 7 days, i limited my light time to 4 hour a day. no worms were visible, but the plants started to get soft due to lack of light. no more algae on the tank, 20% water change was done. still dosing urea for a teaspoon a day.


----------



## Formzero

redchigh said:


> Also, the worms are probably planaria. You could use them as your lab rat animals... And save the poor little guppy.


the guppy is still doing fine, 1 tspn of urea wouldnt hurt for a 30 gallon tank with plants. ^_^


----------



## wet

Formzero - I was dosing about 0.5 ppm N from NH3/4 by my recollection, with the rest of my target coming from the N as NO3 fr CAN and KNO3. (The trick here of course is to isolate the different forms of N. My calc does this for these things, and if you've measurements for your stuff I'm happy to add it.). My goal was to directly replace a reasonable -- by my arbitrary definition, what my plants could uptake in a day -- amount of N as NO3 with N as NH4. And perhaps this is wrong.

This tank had issues with green water, and I believe this experiment contributed. Fast growers, softwater RO/DI plant-only controlled tank, CO2 mist. Pictures:


----------



## Formzero

have you done water changes?


----------



## Zapins

I'm a little late entering this thread, but when I tried using Urea I had algae problems and I was using very low amounts in a 55g. I was also dosing smaller amounts of KNO3 at the time.

Freemann used to dose Urea regularly. He found that using Urea helped make the plant leaves broad and bushy compared to using only KNO3.


----------



## Formzero

Zapins said:


> I'm a little late entering this thread, but when I tried using Urea I had algae problems and I was using very low amounts in a 55g. I was also dosing smaller amounts of KNO3 at the time.
> 
> Freemann used to dose Urea regularly. He found that using Urea helped make the plant leaves broad and bushy compared to using only KNO3.


yes, i had observed that too..but overdosing, could be harmful i guess, to some faunas..


----------



## ray-the-pilot

OK we are at 1 month. How does your tank look?


----------



## Formzero

ill try to post some pictures.. got some green thread algae but i cleaned it up manually. i guess due to excessive nitrates the GTA started to bloom a little..


----------



## Formzero

seems fine.. ^_^

P.S.

i transferred to a 1.5gal tank..


----------



## Formzero

Zapins said:


> I'm a little late entering this thread, but when I tried using Urea I had algae problems and I was using very low amounts in a 55g. I was also dosing smaller amounts of KNO3 at the time.
> 
> Freemann used to dose Urea regularly. He found that using Urea helped make the plant leaves *broad and bushy* compared to using only KNO3.


by the way, thats why in some area the leaves are bigger than the others..since i drop the urea directly without dissolving must be the reason that certain area where i drop it, has a higher concentration made the leaves grow bigger than the others.. just a wild guess..or could be the light..


----------



## ray-the-pilot

Transferring to a new tank means that you have to restart your clock! You lost a whole month!

I want to follow what you are doing exactly so that I get the same results.


----------



## wet

This is a cool little tank. But only a suggestion: build plant mass (cut the stems, dense bushes) first before experimenting with things like Urea. This is because a) it ensures your plants have established and b) such are the tanks that do neat things with funny dosing. These tanks also tend to adapt and recover from mistakes a little easier. (Established stems are hungry and tend to eat our overdosing mistakes.)

I do not think that H. polysperma and R. rotundifolia (?) are established enough yet to judge leaf size. But dose that tank with boring methods while getting trimming practice, and I think the minutia of NH3/4 vs NO3 will be more interesting for your experiments, and that you'll also jude change from knowing the tank and plants's personality a little more. Only my opinion of course! 

Keep updating!


----------



## countcoco

There's a great thread the UKAPS forum about using a solution of urea, kno3, magnesium nitrate, and calcium nitrate. It was developed by a german aquascaper and has received rave reviews on both the UKAPS and flowgrow.de forums.

Solution:

1 liter H2O
25.9g KNO3
29.5g CANO3
17.5g MGNO3
5g UREA

The germans have apparently been dosing urea as a nitrogen source for several years. IMO, I generally think that fert issues are the least important aspect of a planted tank, but this mixture has piqued my interest since so many experienced people have reported massively increased growth after switching from the standard EI KNO3 dosing.


----------



## HeyPK

I did some more experiments with urea, and, again, it killed Daphnia in a tank where there was very little plant mass. Interestingly, the Daphnia didn't die until a week after the urea (one teaspoon of small urea pellets in a 29 gallon) was added. During that week there was growth in a crud-like algae that grows in the mulm that the snails wouldn't eat. The mulm turns green and bubbly, and some of it floats up to the surface. The small plant also died around the time the Daphnia did. The snails didn't die. Makes me think that the Daphnia and possibly also the plant were not killed by the urea directly, but by a byproduct of bacterial action on the urea, possibly ammonia. Another possibility is that the algae produced toxins or allelopathic chemicals that killed the Daphnia and the plant.

In another tank---a 55 gallon---I had a thicker growth of plants, mostly Amazon swords _E. bleherae_, but also an _Aponogeton rigidifolia x crispus _hybrid and some _Eleocharis montevidensis_, the last, mostly floating. In this tank I added half a teaspoon and another half a week later. Here, the Daphnia didn't die and the plants responded with a big increase in growth. Now the tank is packed solid with plants. In this case I think that the plants were able to pick up the urea relatively quickly, and that is why the Daphnia were not harmed.

Conclusions: Urea is a good Nitrogen source, but only if it is given in amounts that the plants can take up relatively quickly. Bad things happen if it stays in solution for many days. You can add more urea if there is a large plant mass in the tank. Be very careful if you have relatively few plants.

29 gallon after urea killed all the Daphnia. The water started to turn green after the Daphnia all died out, and so I cut off the lights. That is why the water looks clear. 









55 gallon before urea.









55 gallon after urea. After I added the urea, the plants started growing, but began to indicate other deficiencies. To correct them I added at various times magnesium sulfate, calcium (in lime), and iron. 









Does anybody want any cheap Amazon swords? I have a lot of trimming to do!


----------



## rikeshpatel85

Hay man as I am new to this field, I have tried so many types of liquid fertilizers, plants and many mote thing and now I got to known that if you are making plants with fishes you need to be very careful.

Now I have some queries

As I am making aquascape with foreground plants and moss I want to know howmuch lights I need to give them my plants are HC cuba, monte carlo, Christmas moss. I have planted my tank with only 3-4 types of plants. THERE IS NO FISH IN MY AQUARIUM, I HAVE 80W OF LIGHT, COMPRESSED CO2 SYSTEM, CANNISTER FILTER WITH BIO FILTER, 63 GALLON OF WATER

Now the questions are
1. How much light I need to give?
2. For howmuch time I need to turn on light?
3. Howmuch co2 I need to add?
4. Which fertilizer I need to use?
5. Can I use urea fertilizer? If yes then howmuch for a week?
6. After howmuch time I need to change the water and howmuch?
7. As I have planted my tank on 22/08/2014 what I need to do for batter development of roots and leaves of plats?
8. Which element is working for root development? 


Please reply as soon as possible.

Thank you,
Rikesh Patel


----------

