# Worm castings (terrestrial) as soil mix



## snowy (Jun 6, 2006)

Failing to find any suitable soil in my tiny, dog contaminated garden, I investigated the compost bin with the intention of mixing a small amount with fine gravel. The compost itself was obviously very high in organic matter and full of sticks, egg shell etc, but when digging it out I noticed that around the sides of the bin the soil was very dark and smooth; it appeared to be primarily composed of worm castings (the compost bin was full of them).

I have mixed a small portion of this soil (about 2 - 3 scoops) with a bucket of fine shale-based gravel and intend to use this as the base layer, covered with smooth gravel the same size as the shale. An overnight bottle test showed little turbidity, although some discolouration was released when the jar was quickly twisted back and forth to release trapped bubbles.

I plan to use this mix in a 50l tropical tank, as well as testing it in 6" pots for pond use. Has anyone else had experience using terrestrial worm castings as a substrate addative in aquariums? A cursory search suggests it has the following properties:



> Worm casting analysis:
> 
> Nitrogen 14.4 % Calcium 1.58 % Phosphorous 0.89 % Potassium 0.34% Magnesium 0.34 %





> ... an analysis of worm castings when compared to the parent soil shows approximately:
> 
> * 7 times the available phosphorous
> * 6 times the available nitrogen
> ...


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## flagg (Nov 29, 2004)

I haven't used worm casting, but looks like they're pretty high in nutrients. I would continue the bottle test for a while longer. What were the water parameters after leaving the casting submerged in your bottle test?

-ricardo


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## snowy (Jun 6, 2006)

I forgot to mention that I did add the following to the gravel mix:
- 1 teaspoon of fine crushed coral.
- 1 teaspoon of mineral salts intended for hardening aquarium water.
These were added to help counter the soft tap water.

I was unable to test it yesterday, but after approx 36hrs the following results were obtained.

Ph - 7.4 (same as the tap water that went in)
Kh - 2.5 (slightly higher than the tap water)
Gh - 6 (higher than the tap water)
NH3 - 0 (just registering)
NO2 - 0.1mg/l (just registering)
NO3 - 10mg/l (0 in tap water)
PO4 - 0.1 (barely registering)

So far it looks encouraging, these results suggest that significant biological activity has been taking place, hence the nitrate level. The turbidity in the jar has also remained clear, with only fine particulate matter being stirred up after twisting the jar.

At this stage I am thinking that I may use all this mix for potting plants that will go in the pond, as I believe the fine shale gravel will help to allow better circulation in the pots, whereas a straight soil mix would probably compact.

If there is some left over then I may combine it with regular topsoil for use in the aquarium.


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## acedia (Dec 23, 2005)

i used worm castings, and fluval grenular peat. i had great results, the week i put my amazon swords in my tank the started runners. i pretty much neglected the tank all winter due to the fact i was working in and out of camps in the oil feilds in northern B.C. it only got top ups(i couldn,t convience my roommates to do maitnence on it ) but it did awsome. ive moved since and it was taken down, but when i am living somewhere where i can actually have all my stuff out of storage i plan to set up another one. 

from what i hear people have mixed results with them but they worked great for me


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## flagg (Nov 29, 2004)

snowy said:


> I was unable to test it yesterday, but after approx 36hrs the following results were obtained.
> 
> Ph - 7.4 (same as the tap water that went in)
> Kh - 2.5 (slightly higher than the tap water)
> ...


Based on these results, it looks fine. I'd give it another week or two, testing the water a couple of days a week. I'd probalby just test ammo. and nitrite and the rest on the last day of your bottle test. My reasoning behind that is that in terms of fish health it's those two parameters that are going to affect their health and you want to make sure that there aren't going to be any sudden spikes and if there are, plan accordingly. Looks very promising so far though! I also thing the crushed coral is a good idea, will help with hardwater nutrients. If you add the crushed coral, I don't think the mineral salts are necessary.

-ricardo


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## sb483 (May 29, 2006)

If you're at all worried about the nutrient levels, you could always play it safe by just buying some potting soil in a bag to use for home aquaria...


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## snowy (Jun 6, 2006)

Well I had an opportunity to get a bunch of cheap plants so I set up a small tank with the worm compost / shale mix as a base. I have started a thread on it  here in the aquascaping forum.

I did add a couple of other ingredients to the mix that I had lying around, namely one tablespoon of fine peat granuals (a semi-fied type) and about the same amount of Terralit, a Zeolite-based substrate. Probably not enough to make a great deal of difference, but perhaps they will have a positive if subtle effect in the long run.


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## dwalstad (Apr 14, 2006)

Dear Snowy,

I took a look at your link to AquaScaping website. What a pretty tank! If the lighting is good, with all those plants, I think they'll handle a rich substrate. If you are adding fish, just check to make sure that the tank is getting enough oxygen.

Bacteria in a rich substrate like this may consume quite a bit of oxygen.

The key will be if the plants take off. If they do, you should be home free!

Let us know how it does.


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## snowy (Jun 6, 2006)

Thanks for the comments, I've updated that aquascaping thread with some new pics etc.

I've been testing the water every day and in the past two days I'd detected a spike in PO4 at 1mg/l. There was none after the initial setup but unfortunately I neglected to test for it on day 2 so I don't know if it built up over a few days or just spiked.

As mentioned in the other thread I suspect it may have been caused by whatever additional fertilizers are contained in the Sera CO2 tabs*, so I have discontinued thier use. I still have the original bottle test going and when I tested the PO4 it was 0, hence blaming the CO2 tabs.

Here's the parameters of the tank setup over the past few days plus comments on what factors I've changed. Any suggestions as to where the PO4 may have come from, if not the CO2 tabs?

I also recorded a jump in the pH, but this dropped dramatically after adding the CO2 saturated water from the Soda Stream. I think I may have over done it with this method so I will leave it for a day and tomorrow add just 100ml.

*Day 1*, Monday 24/7/06
gH - 5°
kH - 2.5°
pH - 7.5°
NH3 - 0 mg/l
NO2 - <0.1 mg/l
NO3 - 0 mg/l
PO4 - 0.1 mg/l
After test added 1/3 sera CO2 tab.

*Day 2*
kH - 2.5°
pH - 7.5°
NH3 - 0 mg/l
NO2 - <0.1 mg/l
NO3 - 0 mg/l
After test added 300ml of CO2 saturated water + 1/3 sera CO2 tab.

*Day 3*
gH - 6°
kH - 3°
pH - 7.8°
NH3 - 0 mg/l (even less of a green tinge that previous readings)
NO2 - <0.1 mg/l
NO3 - 0 mg/l
PO4 - 1 mg/l
After test added 300ml of CO2 saturated water. Pearling noticed almost immediately.
Sera CO2 tabs discontinued on suspicion of raising phosphates.
Cannister filter with activated carbon replaced with powerhead.
10% water change with aged and dechlorinated water.
3 hrs later:
gH - 6°
kH - 3°
pH - 6.5°

*Day 4*
gH - 6°
kH - 3°
pH - 7.5°
NH3 - 0 mg/l
NO2 - <0.1 mg/l
NO3 - 0 mg/l
PO4 - 1 mg/l
No CO2 added today.

* edit: When in doubt, read the instructions! The Sera CO2 tabs list the ingredients as: 'citrate, hydrogen carbonate, KSO4, MnSO4, trace elements'


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