Using Potting Soil to Boost Aquatic Plant Growth

[Theplatymaster]

This has probably been tested before, im trying myself.

The preface to this project was mostly watching MDfishtanks videos, how most of his tanks use a capped nutrient layer, and i thought id test it. But using dirt wasnt really a good option(Suprising i know right). However i remembered that i have a big bag of potting soil in the garage, and its similar to dirt so hence my experiments.(Also i have some crypts i want to grow big)

Container:Pretzel Container

Water Volume: ?

Lighting: Ambient room light, and light from the window next to the container

Substrate: Potting Soil Capped with Sand

Plants for testing: I have Crypts that i will be using in this test, mostly because i want them to grow bigger, hence the potting soil idea. But i will also be testing Java Fern, and Elodea.

Note: This is not a very scientific approach, i have no control, take this with a grain of aquarium salt. Im just trying to grow crypts bigger, and posting it here.

Hypothesis: If potting soil capped with sand is used for Cryptocorynes Then they will grow faster.

Initial water testing results, (Im looking only for potential nutrients): Ammonia:0ppm Nitrite:0ppm Nitrate:0ppm. Nothing released into the water column (yet). When i was filling it up, a tiny bit of potting soil got uncovered so there is a tiny bit floating around, most of it is under sand though.

Time to add plants:

As i said this is not a super good experiment. The basket with the crypts was burried to the bottom, with the top of the basket not covered so the crypts can utilize the soil. Elodea/anarchis, was simply planted in the sand, and the rock with java fern, was placed on the sand. If i was better at this id have like 7 of these setup for controls, but i dont ill see what happens.

Here is a picture of the jar after planting:

photography was hard, the water was cloudy from the sand.

[Guppysnail]

Anything dealing with organic soil I would ask  @Streetwise  

If I remember correctly he had better luck capping with gravel than with sand. 

[Fish Folk]

Is there any information on the potting soil bag about added Nitrates / nitrogen?

[Theplatymaster]

On 2/3/2023 at 9:51 AM, Guppysnail said:

 

If I remember correctly he had better luck capping with gravel than with sand. 

thats probably true, im using sand, because i have a bunch of it extra lying around. Also @Streetwise and me have had some discussions before, he might have tested stuff before me, but that doesn't mean i wont try it. We had a whole argument on mosses, he said terrestrial mosses cannot be grown submerged, in my experience after a long melt back period, they will grown fine submerged.

also @Fish Folk good question i could check the bag. Besides the videos i watched, i didnt do much research. Ill check the bag though should be interesting.

Edited February 3, 2023 by Theplatymaster

[Theplatymaster]

@Fish Folk i have checked the bag, there is Nitrogen content in the form of Nitrate but it is low.

[JettsPapa]

On 2/3/2023 at 8:46 AM, Theplatymaster said:

This has probably been tested before, im trying myself.

The preface to this project was mostly watching MDfishtanks videos, how most of his tanks use a capped nutrient layer, and i thought id test it. But using dirt wasnt really a good option(Suprising i know right). However i remembered that i have a big bag of potting soil in the garage, and its similar to dirt so hence my experiments.

I've been watching quite a few Father Fish videos lately, and he's made a believer of me.  I have a tank I set up in November 2021 with a 1" layer of mixed dirt and dry cow manure (I have cows, so it wasn't hard to get), then a 1" layer of a good quality potting soil, and capped with a 2" thick layer of pool filter sand.  I initially planted it with pearl weed, because a LFS said he'd buy it from me, but when I went to sell him some he had decided to grow his own and only gave me store credit for it.

I ripped it out and planted crypts.  They're doing very well.

Edit:  Since setting up that 20 gallon tank I've broken down three of my four 10-gallon tanks and re-did them (and the fourth one's turn is coming soon) with deep substrate.  I couldn't bring myself to put 4" of substrate in a tank that small so I skipped the potting soil layer on those.  Of course they're newer tanks, but the plants are doing well in them also.

Edited February 3, 2023 by JettsPapa

[Sharon M]

I would love to try this. 
I use Coast of Maine Ocean Forest for my houseplants, and they thrive.

I just keep thinking it would make a soupy mess.

 

[JettsPapa]

On 2/4/2023 at 7:24 AM, Sharon M said:

I just keep thinking it would make a soupy mess.

That's what the 2" layer of sand is for.  If you're careful to not disturb it when adding water it won't be any more soupy than if it didn't have the soil layer.

I usually spread a towel out on the sand and pour the water onto it carefully.

[Expectorating_Aubergine]

You'll get good growth. Sand will increase the chances of the soil going anaerobic. Gravel is what most people use. The only real issue with using potting soil as a substrate is that the nitrogen source for the soil is ammonia. Not that big a deal if it's a plant only tank, or you're letting the plants grow in first before the fish. However, if you're adding fish in straight away....... be careful. The again, I'm the kind of guy that adds dry ferts to his tank with the fish in there and everything...

[Up North]

I use organic soil and mix in a bunch of worm castings then a layer of oak leaves and top with 2" of sand. 

[JettsPapa]

On 2/4/2023 at 1:54 PM, Up North said:

I use organic soil and mix in a bunch of worm castings then a layer of oak leaves and top with 2" of sand. 

I hadn't thought of adding a layer of leaves.  I may try that with my next tank.

[Birdsnstuff]

I don't have any recent experience with fresh dirt/potting soil aquariums but I do have a 15long that I set up with good ol' arkansas dirt from the backyard back in 2003. I had read the Walstad book in 2002 and decided to try it. I soaked the soil for a very long time and still probably added the fish too soon. My knowledge of cycling, ammonia, etc wasn't very deep. But eventually it settled down (literally and figuratively), I covered it with gravel, and planted it with plants that were available to me at the time. It's had its ups and downs depending on how much I was paying attention to it but I kept 3 of your basic corydoras (with a varying cast of friends)  alive for a dozen years with very little algae. I have crypts that have been in the tank for years along with java moss and Anubias. I decided to cap the gravel with sand recently to be kinder to some Habrosus corys. I think the sand cap has improved the tank - It seems healthier. I did put a few flourish tabs under the current crypts to replenish the soil a bit and planted some new species of plants to mix it up a bit. It's still relatively algae free. 

I have a 40 breeder I'm slowly working towards setting up. I'm slowly moving towards a soil/sand substrate. I have a 20H that has ancient Flora Max soil - plants grow but it's fussier and the tipping point towards hair algae seems to be easier to get to. I'm always curious to see what others do/ try for their soil substrate tanks.

Edited February 6, 2023 by Birdsnstuff
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