Miracle Gro Potting Soil vs Garden Soil

Everyone gives rave reviews of Miracle Gro Organic Potting Mix, and everywhere I see it, "STAY AWAY FROM THE GARDEN SOIL!" Here's the thing, I just checked the ingredients and they're identical. Both contain composts and a wetting agent which, who knows what that could do to an aquarium. After reading reviews, however, I used the potting mix in my 3 gallon cube where the old betta, shrimp, snails, and plants thrive and continuously grow for 5 months, so much that I have to trim every 2 weeks, otherwise the plants take over. The ramshorns are breeding (they don't fare well in my water), pH has buffered to 7 (tap is 6.8), all algae died many months ago, and the tank's been going strong! Of course, it's with Miracle Gro Potting Mix, which is the main one aquarists suggest. But the only difference is the garden soil has about 1/3 of the nitrogen, phosphorus, and potash...so the same but with less nutrients, which is better for lightly or moderately-planted tanks than heavily-planted ones.

Some people say using topsoil is the best option (including SerpaDesign, a youtuber I've been subscribed to for 7 years) because of the lack of added ingredients, and although it's MUCH cheaper, it's an unpopular opinion. Most often, folks use potting mix, and every tank is successful.

What's everyone's opinions on this? Do you use expensive organic soil that allegedly has no added ingredients (which is impossible to know for sure), a type of Miracle Gro, topsoil, or something else?

 

Some potting soil has these little white chunks that float forever and and make a mess in the aquarium!

Some potting soil and some topsoil turns the water black and it never clears.

I prefer to use something labeled for aquariums to avoid these time consuming issues.

 

What's everyone's opinions on this?

I'm definitely on team soil. I, like you, have noticed huge improvements in plant growth after using soil.

In regards to collected topsoil vs. storebought, I think it depends. I've used both, and I've had success with both. But, some folks haven't had the same success. I think this is because not all soil is the same. In fact, it can be quite different. Some soils work well, while others cause problems. Therefore, collecting your own soil is a bit of a crapshoot. This is why I think using a brand of potting soil that others have had success with is a safer bet. It's more likely to be similar.

Do you use expensive organic soil that allegedly has no added ingredients (which is impossible to know for sure), a type of Miracle Gro, topsoil, or something else?

It depends on my tank and what I'm going for. I've used Miricle Gro, topsoil, and those expensive baked soils like Aqua Soil and Controsoil. In my experience, they all work well. Going forward though, I'm unlikely to use regular topsoil, because it's not as standardized. That organic Miracle Gro soil seems to work consistently well. Also, those expensive baked soils are nice if you're going to be moving and/or replanting plants often (like in a high-tech Dutch style tank), because they aren't nearly as messy.

 

Some potting soil has these little white chunks that float forever and make a mess in the aquarium!

The little white things are perlite - crushed volcanic rocks. Safe for fish, highly nutritious for plants, and a home to beneficial bacteria! Here's the thing...it's often made from siliceous lava (meaning it has silica) which can cause diatom blooms but honestly, those aren't an issue in terms of tank or inhabitant health, they're easy to clean, help clean your tank, and typically go away in a healthy planted, established, or Walstad tank with time

Some potting soil and some topsoil turns the water black and it never clears.

As for turning water black, I've never seen that before. Did you have a filtered tank or sand-sifting fish because if so, that'd make sense. I use the Walstad Method (capped soil, med-high lighting, no filtration). I've never had that with 2 different brands of plant soil.

I prefer to use something labeled for aquariums to avoid these time consuming issues.

Aquasoil, controsoil, stratum, etc are literally baked, compressed, shaped topsoil that can eventually break down, turn back into mud, and make a mess. It's not special, costs nothing to make, but prices are outrageous! For dried mud balls!

 

I don't care for potting soil in aquariums as I do low nutrient habitats and I'm known for being ignorant about brands, but I have one thing to comment:

pH has buffered to 7 (tap is 6.8)

0.2 is within the error margin of available aquarium pH tests and the neutral range is 6.8 to 7.2.
So that doesn't mean much in my opinion.

 

The question is what you like to achieve with the soil.

If the answer is "lush growth", you can get this pretty much with any substrate, inert substrates included. At the end of the day, you need to add nutrients. Via which channel or vehicle you add them, it doesn't matter. Nutrients reach the leaves and the substrate. Besides, plants adapt. They can take up nutrients via leaves and roots. If CO2 in the water column is lacking, plants take up CO2 produced by microbes via the roots.

Dosing fertilizers in the water column is what I think what most seasoned planted tank hobbyists rely on the most. Just stroll for a few minutes, or hours, on planted tank fora. The benefit of this approach is, you know what you are adding and you can control timing. Oftentimes, availability of nutrients is not the issue. Accessibility is.

Are all the others crazy for working with rich substrates? And capping it with a layer of gravel or sand? No, because at the end of the day, plants need their nutrients. With a rich soil, you have plenty of nutrients in the first months of course.

Working with layered soils seems intuitive, because soils in nature are layered. It might even look professional or advanced. But it can be a pain in terms of replanting and rescaping. And importantly, it doesn't represent nature. The flux of organic and inorganic compounds in the substrate is different in a small tank with a glass bottom. And most of the plants in the hobby are not found in nature the way we keep them. Many hail from areas with dry and wet seasons.

Can substrates have too many specific nutrients? What is the effect of this on the intake of other nutrients? Is it helping or blocking? Because plants are so adaptable, you probably won't even know and people continue to give credits to the soil. Or root tabs.

I like to keep things as simple as possible. A sand only substrate works just fine. In low tech, tap water is pretty much all I need. In high tech, I would need to dose fertilizers, but lush growth is determined by CO2 mostly.

 

I have noticed from watching multiple indoor and outdoor garden U tube videos that the names used in the UK and US are completely different to what we call potting mix, seed raising mix , compost and dynamic lifter . We don’t have a bag of soil sold under any name. Peat moss is considered a non renewable and is hard to find . It’s almost illegal to sell in my state.
I am not taking anything away from what is written above.
Sitting down after a few hours messing around in the garden and having opened a bag of plant and soil booster and potting mix I just feel this is one of those situations were names mean very little and it’s the ingredients that matter. Or each of us can only listen to people in the same country.
Trust me you would not put ether of these bags in an aquarium.

As far as garden soil . I believe our dirt is very different from the top soil in the UK .

 

The little white things are perlite - crushed volcanic rocks. Safe for fish, highly nutritious for plants, and a home to beneficial bacteria! Here's the thing...it's often made from siliceous lava (meaning it has silica) which can cause diatom blooms but honestly, those aren't an issue in terms of tank or inhabitant health, they're easy to clean, help clean your tank, and typically go away in a healthy planted, established, or Walstad tank with time

Perlite is inert. It's mostly silicon and aluminum (about 90%). It's used to increase aeration and drainage in potting soils. Being inert, it will not cause diatom blooms or provide nutrients to plants.

"Perlite is neutral with a pH of 7.0–7.5, but it has no buffering capacity and contains no mineral nutrient." -Sciencedirect.com

 

The question is what you like to achieve with the soil.

If the answer is "lush growth", you can get this pretty much with any substrate, inert substrates included. At the end of the day, you need to add nutrients. Via which channel or vehicle you add them, it doesn't matter. Nutrients reach the leaves and the substrate. Besides, plants adapt. They can take up nutrients via leaves and roots. If CO2 in the water column is lacking, plants take up CO2 produced by microbes via the roots.

Dosing fertilizers in the water column is what I think what most seasoned planted tank hobbyists rely on the most. Just stroll for a few minutes, or hours, on planted tank fora. The benefit of this approach is, you know what you are adding and you can control timing. Oftentimes, availability of nutrients is not the issue. Accessibility is.

Are all the others crazy for working with rich substrates? And capping it with a layer of gravel or sand? No, because at the end of the day, plants need their nutrients. With a rich soil, you have plenty of nutrients in the first months of course.

Working with layered soils seems intuitive, because soils in nature are layered. It might even look professional or advanced. But it can be a pain in terms of replanting and rescaping. And importantly, it doesn't represent nature. The flux of organic and inorganic compounds in the substrate is different in a small tank with a glass bottom. And most of the plants in the hobby are not found in nature the way we keep them. Many hail from areas with dry and wet seasons.

Can substrates have too many specific nutrients? What is the effect of this on the intake of other nutrients? Is it helping or blocking? Because plants are so adaptable, you probably won't even know and people continue to give credits to the soil. Or root tabs.

I like to keep things as simple as possible. A sand only substrate works just fine. In low tech, tap water is pretty much all I need. In high tech, I would need to dose fertilizers, but lush growth is determined by CO2 mostly.

Thank you friend! I actually conduct experiments on heavily-planted fishless containers. Some are windowsill tanks, others have LED lighting. Right now I'm trying 6 substrate fertilizers; miracle gro slow-release, osmocote, API tabs, seachem tabs and 2 miracle gro soil types. 6 liquid ferts; thrive, API, aqueon, easy green, seachem flourish, even miracle gro water soluble fertilizer. Control tanks too (coconut fiber, big gravel, small gravel, sand, and even barebottom.) Unfortunately, due to low funds, most experiments aren't set up yet and a few that are aren't anywhere near completion. I probably need at least a few months to a year

 

I agree that it's entirely possible to grow healthy plants in sand. I've done it myself, even with plants that are supposedly heavy root feeders. That being said, I've also had several failures using sand, but I can't recall having those same failures with soil.

Even with tanks that are growing healthy plants, I still notice a difference with the ones that have soil. In my experience, plants just seem to grow fuller in soil than they do sand. It seems to me, using soil provides a greater margin for error that just using sand. Here is my hypothesis as to why that might be:

Sand has a poor Cation Exchange Capacity (CEC), while soil has an excellent one. This means soil holds onto nutrients much better than sand, making those nutrients available to the plants. Perhaps this is why it seems to work better/more consistently for me. Soil may be acting like a nutrient bank in between fertilizations, making those nutrients more consistently available.

 

I agree that it's entirely possible to grow healthy plants in sand. I've done it myself, even with plants that are supposedly heavy root feeders. That being said, I've also had several failures using sand, but I can't recall having those same failures with soil.

Even with tanks that are growing healthy plants, I still notice a difference with the ones that have soil. In my experience, plants just seem to grow fuller in soil than they do sand. It seems to me, using soil provides a greater margin for error that just using sand. Here is my hypothesis as to why that might be:

Sand has a poor Cation Exchange Capacity (CEC), while soil has an excellent one. This means soil holds onto nutrients much better than sand, making those nutrients available to the plants. Perhaps this is why it seems to work better/more consistently for me. Soil may be acting like a nutrient bank in between fertilizations, making those nutrients more consistently available.

That makes sense! Well, every goldfish tank kept had sand since they prefer sifting through it, and plants. B. caroliniana, H. polysperma, pennywort, H. corymbosa, C. parva, A. congensis, jungle val, A. nana, A. 'petite', vallisneria, dwarf sag, 3 types of java fern, sußwasstertang, egeria, and riparium plants like peace lily, pothos, aluminum plant, and chinese evergreen. Even though it had only sand, I suspect the high stock and lack of uprooting (well-behaved goldfish) was what kept it good. I didn't even fertilize weekly - I kept forgetting! Could've also been my tap water too...it's liquid gold!

 

Sand has a poor Cation Exchange Capacity (CEC)

Poor? None. Sand is usually and ideally absolutely inert and contains no nutrients at all. With sand the nutrients have to come from somewhere else.

Soil doesn't hold on to nutrients, it is partially just made up of them, as it is a mix of silt (containing minerals), humus (organic matter, the main portion containing nutrients), compost (larger particles of dead plants) and often a bit of fine sand and gravel.

I suspect the high stock and lack of uprooting (well-behaved goldfish) was what kept it good. I didn't even fertilize weekly - I kept forgetting! Could've also been my tap water too...

Yes, the right stocking density and sufficient mineral content in tapwater can be all that it needs.

 

Soil may be acting like a nutrient bank in between fertilizations, making those nutrients more consistently available.

If you look at starting points, yes. With different substrates, you have different starting points. Different rates. Different routes. What they have in common is a similar directional flux of nutrients, as the total layer is shallow (less than 12 inches I presume) and blocked by a glass bottom.

Eventually, the traits of different substrates converge, dictated by living (and dying) organisms, water changes and possibly added fertilizers.

Initially sand is clinical, but over time, it becomes alive. Debris (high CEC) (and fertilizers) finds its way in the sand and plant roots form a symbiotic relationship with decomposers and decomposers with detritivores.