How to Boost Root Growth in Aquarium Plants

So you want to try keeping stem plants, carpets, rosettes, bulbs, or other rooted plants in a planted tank, but after buying your first few, they ain’t looking too hot. Keep watching as I reveal the top 5 things I’ve learned so far about growing healthy roots for healthy plants!

When I first started dipping my toe into the aquascaping world, I went with your beginner plants – java fern, anubias, bolbitis, and so on. What do all of these have in common? They’re rhizome plants that that you can pretty much glue to a rock and treat it like a piece of aquarium decor. Very hardy, don’t need much light, hard to kill.

Eventually, I wanted to broaden my horizons and get into the world of rooted plants that actually need soil or substrate to live in. That totally opened up my options to stem plants, carpeting plants, crypts, bulbs, you name it! I mean, we’re talking level 2 stuff here, right? Hah! That also means I had to be prepared to face level 2 problems and outright failures. So, come along with me as I reveal the lessons I’ve learned so far when it comes to growing healthy roots for healthy plants!

Tip 1: Leaves may melt off after you first plant them

First off, I learned that at the plant farms, most aquarium plants are actually grown emersed (above water with only their roots and substrate covered in water) rather than submersed (grown entirely underwater). Crazy, right? The reason why they do that is because aquatic plants grow much bigger and faster when they have unlimited access to carbon dioxide from the air, and their leaves are also free of algae and snail eggs. However, when we take those emersed grown plants and plunge them into the water, those leaves go into shock and often melt off, leaving you to think that you bought a dud. Don't throw the plant away! Leave it in your tank, cut off any dying, emersed grown leaves, and eventually the new submersed grown leaves will pop out, probably looking a little smaller and shorter than before. You’re essentially paying for the healthy roots on a plant, not the leaves.

Emersed vs. submersed grown leaves on a crypt parva (source: spec-tanks.com)

Tip 2: Don't move your rooted plants if at all possible

Once you’ve picked a spot for your new plant, don’t move it. Unlike rhizome plants that allow you to frequently redo your aquascape just by moving the stone or driftwood they're attached to, rooted plants need time to settle in and become, well, rooted. Every time it gets uprooted – whether because you’re rescaping, you accidentally bump it when gravel vacuuming, or you have a jerk of a fish who likes to dig – you’re basically pushing the reset button for that plant and it has to get used to its surroundings all over again. It’s not going to grow well until it feels nice and stable for a while. (P.S. Plant weights can help keep your plants down until they grow more roots.)

Tip 3: Make sure the substrate is deep enough to grow roots

So, what’s the best way to make a rooted plant feel nice and comfortable? Well, I’m not going to get into a big debate about which brand of substrate is superior. Just remember: regardless of what kind you choose, make sure you use enough of it. Some of you might be tempted to buy something really high quality and expensive, which means you may not have the funds to get a lot of it. Most planted tank sources recommend a total substrate depth of 2 to 3 inches (or 5 to 8 cm). That way your plants have enough room to grow deeper roots and not get uprooted at the slightest touch.

Tip 4: Pay attention to the particle size of the substrate

Speaking of substrate selection, I know I just said that I didn’t care what kind you bought. That being said, you have to make sure the substrate particles aren’t too big or too small. If you go too big and have the equivalent of river rocks for your ground cover, the gaps between the stones are too wide and the roots won't anything to hold on to. (Again, I’m talking about rooted plants, not rhizome ones that can hold on to practically anything.)

River rock is too big of a substrate for most planted aquariums (source: Reddit)

If you go with a really fine sand, like Caribsea Super Naturals sand, there’s hardly any space between the particles for the roots to grow in. The sand is going to compact way too much and end up smothering the roots to death. Therefore, if you want to use sand, make sure it’s much coarser and larger in diameter, like Seachem Flourite black sand.

Tip 5: Use fertilizers to enhance root and shoot growth

Okay, so you’ve got your perfect substrate, you’ve planted your rooted plants, and you pinky swear not to move them. But they’re still not thriving and staying rooted for some reason. What else can really encourage good root growth? First off, if you're using an inert substrate that doesn't innately contain any nutrients, don't forget to add fertilizers into the substrate in the form of root tabs. Most aquarium plants consume nutrients from the ground and from the water column, but which one they use more depends on the species.

Another tip I heard was from Aquarium Co-Op, a retail and online store that sells live aquarium plants. Remember in the beginning of the article , where I talked about emersed versus submersed grown plants? Well, when Aquarium Co-Op gets their shipments from the plant farms, they actually try to start the process of converting plants to submersed grown, and their secret sauce for encouraging roots to grow faster is using a combination of their own Easy Green all-in-one fertilizer and Seachem Flourish Advance. Flourish Advance is described as a natural phytohormone supplement that “dramatically stimulates the growth of both roots and shoots in aquatic plants.” The ingredients include potassium, phosphates, calcium, and magnesium, which are some of the basic building blocks for plants.

Aquarium Co-Op starts converting plants to submersed growth before selling to customers

When I was having problems with plants staying rooted in my betta tank, I started adding this magical juice to my regular Easy Green dosing, and boom, no more floating plants! It’s too early to tell whether or not this definitively works for me, but Aquarium Co-Op is buying this stuff by the gallons so you can be sure they wouldn’t be wasting their money if it wasn’t worth it.

Question of the Day

What are some lessons learned about planted aquariums that you wish you'd known as a beginner? Comment below to share, and I may include them in the next plant tutorial article. If you missed Part 1 of this series, check out my 5 Tips for Starting Your First Planted Aquarium. Take time to enjoy your aquariums, and I'll see you next time!

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