So, you’re here because you’re wondering why do plants grow roots in water, right?
It’s an excellent question, especially since most plants grow in soil, but (as most plant parents will know) can quickly die from overwatering.
Which begs the question – why do plants grow roots in water, but die in wet soil? Well, it’s all to do with how plant propagation works.
Keep reading and I’ll answer all your questions about how plants grow roots in water, including why do plants grow in water and how do plants grow in water without soil.
Why Do Plants Grow in Water?
This is a tricky question to answer, because it depends if we’re talking about aquatic plants that exclusively grow in water, or plants that survive in water when propagated or planted in a hydroponic system.
Before we get started, here are some quick definitions of the above:
- Aquatic plants: Live exclusively in water, like ponds, swamps, rainforests, lakes, etc.
- Propagation: Means taking cuttings from plants and placing them in water until new roots (and eventually new plants) grow
- Hydroponics: Means growing plants, usually vegetables, in water trays fitted with an air pump, typically in a greenhouse, to speed up growth rates and reduce pests
Aquatic plants: How do plants grow in water only?
First, let’s answer the question about aquatic plants and why they grow in water. The answer is simple.
Aquatic plants natively live in wet environments, like ponds, lakes, or swamps. These plants grow in water because they’ve adapted to the environment around them.
Because there’s no soil present, their roots have learned to not root in soil, and instead float around freely in water, getting all the nutrients they need from the water around them.
Propagated plants: How do plants grow in water only?
Some plants can be propagated in water, which means you take a cutting from a plant (like a leaf or stem), place it in water, and watch it grow roots.
Once the roots have formed, you can usually transfer the cutting into soil and grow yourself a new, identical houseplant!
Many houseplants can be propagated in water, but some won’t be able to grow to their full potential in water, nor will they survive a transition to soil in the future.
It’s important to learn how to propagate your houseplant properly before you start to ensure you achieve what you want to achieve.
Or you can just do what I did and experiment with propagation, learning as you go. It takes a LOT longer, but can be quite rewarding when you finally get it right!
Related article: How to propagate snake plants in the BEST way
Hydroponics: How do plants grow in water only?
Hydroponic systems are usually used in greenhouses to grow fruits and vegetables without the need to purchase expensive soil or deal with soil-related pests.
Growing plants hydroponically usually involves placing plant roots in opaque trays filled with water.
These trays are fitted with a water pump to ensure the water is oxygenated. The water is also regularly fertilized to ensure the plants get the nutrients they would’ve gotten from soil.
The only reason these plants can grow hydroponically (in water only) is because the water has been modified to provide the same nutrients as they’d get from soil.
How Do Plants Grow in Water Without Soil?
Plants grow in water without soil either because they’ve adapted to do so, or because the water has been modified to provide plants with everything they need to survive.
Some plants, like aquatic plants, have adapted to survive in just water. More specifically, they’ve learned how to survive in the specific water conditions around them.
It’s why if you decide to grow plants in a new garden pond, you’ll need to create the perfect water conditions for them to survive.
Other plants, like plants grown hydroponically (in water only, usually in greenhouses) do not natively grow in water. However, the water has been modified to enable them to survive in it.
For example, air pumps are usually fitted in the water to ensure it contains enough oxygen for the plants. It’s also routinely fertilized to ensure it contains enough nutrients for the plants to grow.
Why Do Plants Grow Roots in Water?
There’s a highly scientific answer I could give to this question, but, after reading tons of research on the subject, the answer can be simplified quite significantly.
Essentially, some plants grow roots in water because they have the ability to do so. I know that sounds like the vaguest answer ever, but it’s true!
Some plant cuttings (when they’re healthy and taken from a plant that can be propagated in water) will grow roots in water because the cutting contains the enzymes, proteins, and auxins to do so.
Other plant cuttings can’t be propagated in water (and therefore won’t grow roots in water) because they don’t have the properties to do so.
It’s as simple as that. Some plants can do it, while others can’t.
Why Do Plants Grow Roots in Water, But Die in Wet Soil?
This is another excellent question. It would make sense that if a plant can grow roots and thrive in water when propagated, why does it die when its soil is overwatered?
Well, the answer relates to how much oxygen the plant gets.
When you propagate plants in water, you should change it regularly to ensure the cutting has enough fresh, oxygenated water to grow roots.
When you grow plants in soil, overwatering can quickly lead to a lack of oxygen in the soil. It can also lead to harmful bacteria sprouting. This can cause your plant roots to rot or become infested with pests.
So, why do plants grow roots in water, but die in wet soil? Because the soil, when saturated and waterlogged, is no longer full of good nutrients, but harmful bacteria instead.
Have you learned something new about how propagation works? Did you already know these facts about plant roots? Let me know in the comments! 😊
