Best Water Propagation Methods for Houseplants
You’ve heard of Prop Drops, and you’ve heard of SUPERthrive Vitamin Solution, but which product is really the best at getting your plant water propagations to root? In this post, we’ll be reviewing 4 of the most popular water propagation aids— Market Botany Prop Drops, SUPERthrive Vitamin Solution, General Hydroponics RapidStart, & Pothos propagation water— to get to the bottom of which method is actually the most effective for rooting new stem cuttings.
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First, let’s discuss the 4 water propagation methods we’ll be comparing and a little bit about their method of action.
The Water Propagation Methods
The first product we’ll be reviewing is one you’ve probably seen marketed heavily all over TikTok, which is Market Botany’s Prop Drops Root Growth Accelerator. You simply mix 4-5 drops of this solution in 16 oz of water, and this product is supposed to accelerate the root growth of your plant. The active ingredient in Prop Drops is indole 3 butyric acid (or IBA for short), which is a synthetic plant hormone that is responsible for regulating root growth and development.
We’ll be comparing the IBA rooting hormone found in Prop Drops to the second method, which is your basic Pothos cutting. You may have heard that putting Pothos cuttings in your propagation water will speed up the rooting time for other plants in the same container. It turns out that Pothos (scientific name ‘Epipremnum’) contain an excess amount of naturally-occurring rooting hormones called IAA. In other words, it’s basically the naturally-occurring form of the synthetic rooting hormone found in Prop Drops.
The third method we’ll be reviewing is SUPERthrive Vitamin Solution, which has received a cult-like following amongst some houseplant enthusiasts on the internet. But depending on who you ask, people describe SUPERthrive as either a miracle solution or total snake oil. Apart from a really small amount of nitrogen, the only other active ingredient in SUPERthrive is Vitamin B1. And despite all of the miraculous claims made on the SUPERthrive bottle, the scientific research doesn’t really support Vitamin B1 being very effective for root growth.
The last product we’ll be reviewing is the somewhat lesser-known General Hydroponics RapidStart Rooting Enhancer. Now from the ingredients and documentation on the internet, I could not actually figure out how this product was actually purported to work. But I contacted the company, and while the reply was in broken English, I was able to figure out that this product does not contain any plant hormones like IBA or IAA, and instead contains botanical extracts and minerals that are supposed to support root growth by turning juvenile plant cells into rooting cells.
The Experiment
I added the recommended amount* of each water propagation product to 16 ounces of water. In each glass, I put one fresh Scindapsus Platinum cutting. For a control condition, I also placed a cutting into just a plain glass of water without anything else added. All of these glasses were placed in my tall DIY Greenhouse Cabinet so I could ensure each of them received the same exact growing conditions. I then measured the number and length of roots that emerged each day.
*I couldn’t find much information on how much rooting hormone would be emitted from a single Pothos cutting, so I decided to add one Pothos cutting to one glass and three Pothos cuttings to a second glass just to see if it makes any difference.
The Results
After allowing the Scindapsus cuttings to root for 1 month in my greenhouse cabinet, these were the results!
H20 Effectiveness: The cutting in plain H20 produced 2 roots, each about an inch long. For this experiment, I did not change out the propagation water because I wanted to solely evaluate the effect of my conditions, and also because it more closely mimics what most of us plant parents do in the real world. However, I think its important to note that the plain water condition was the only cutting that developed some amount of root rot. If you disregard the rotted roots, each root is about 0.5 inches long, or 1 inch in length total.
Pothos Cuttings Effectiveness: Regardless of the number of Pothos cuttings that were added to the glass, each Scindapsus cutting produced 1 root about 1 inch long. So, almost identical to plain H20, minus the root rot. However, the Pothos cuttings actually rooted more substantially than either Scindapsus cutting.
Prop Drops Effectiveness: In terms of root length alone, Prop Drops was the clear winner. The Scindapsus cutting produced a root measuring 5 inches in length. It was healthy with no signs of rot, and it looks like it was about to start producing secondary roots.
RapidStart Effectiveness: Despite not containing any rooting hormone, RapidStart was also pretty effective. The cutting produced a single root about 4 inches in length (so just a bit shorter than Prop Drops) and was in good health. Something unexpected was that the RapidStart solution turned green due to algae growth. I theorize that this is because, out of the three products I tested, RapidStart contained the highest levels of nitrogen, potassium, & phosphorus, which are the 3 primary nutrients that plants need to grow. There were likely more nutrients in the solution than one small cutting could uptake, so algae was able to grow and multiply itself pretty easily.
SUPERthrive Effectiveness: This result shocked me. SUPERthrive…. did absolutely nothing. Okay, it produced a little nub about 1/8 inch long, but it did significantly worse than all other conditions, even plain H20. I wasn’t expecting that!
Final Conclusion
Does Pothos water speed up root growth?
Under most circumstances, putting Pothos cuttings in your propagation water probably isn’t going to do much for speeding up the rooting of your cuttings compared to just plain H20. Kind of a bummer, since it’s the only free option, but it is what it is.
Does Prop Drops speed up root growth? Does RapidStart speed up root growth?
We can conclude that both Market Botany Prop Drops & General Hydroponics RapidStart do significantly speed up the rooting process for stem cuttings. So, if you’re spending money on them (or are thinking about it), you can rest easy at night knowing its not just a placebo effect. However, I would reach for them in different scenarios.
Prop Drops did work the best in our experiment overall, probably because it contains the plant hormone responsible for triggering root growth. As a result, I think it is the best option for rooting new stem cuttings.
However, if you have an established plant with an existing root system that needs a little more support, then I would reach for RapidStart. Studies shown that using rooting hormones like the ones found in Prop Drops for long periods of time can negatively affect the health of a plant, and something of note is that the leaf on the RapidStart cutting actually looked a lot healthier compared to the Prop Drops leaf. Again, this doesn’t really matter for a small propagation, but for a larger plant you might care what the leaves look like. I personally use RapidStart when transitioning a plant from soil to LECA or pon, and I find it works great for that.
Is SUPERthrive Vitamin Solution bad for plants?
The cutting placed in the SUPERthrive solution failed to root at all. Does that mean SUPERthrive is it bad for your plants? My personal opinion: I don’t think that’s the takeaway here. Rather, I think that SUPERthrive does not contain the ingredients that create the necessary environment to trigger a propagation to begin rooting. It does contain nutrients that plants need— in fact, my favorite fertilizer, Foliage Pro, contains SUPERthrive— but SUPERthrive’s Vitamin Solution alone does not contain the nutrients that are going to encourage a new stem cutting to begin creating roots. It’s not just the right tool for the job!
Did these results match what you expected? What planty experiment should I conduct next?
