If you’d like to style your home or office with plants, but are not sure you’ll always remember to hydrate them, how about growing them in water. Provided you have the right amount of light and know which plants thrive in water only, you can have as many plants as you want.
In this post, we’ll look at a few indoor plants that can live in water and we’ll see how to care for them. But first, let’s find out what plants need for growth.
What do plants need to grow?
Plants need three nutrients to make their food. These are carbon, hydrogen, and oxygen. Carbon and oxygen come from carbon dioxide in the air, while water supplies hydrogen and more oxygen.
To make their food, plants must combine carbon, hydrogen, and oxygen to form sugar using energy from sunlight. That is the process we know as photosynthesis. Without carbon dioxide, water and sunlight, plants cannot grow. But that’s not all.
Like all living things, plants also breathe. They take in oxygen in the air through their leaves and roots. Oxygen is used to convert the sugar they make into energy to function and grow.
Plants grow by building new cells and tissues. They need six additional nutrients to do this. These are nitrogen, phosphorous, potassium, sulphur, calcium, and magnesium. Each of these is a component of cells and tissues that form new leaves, roots, stems, flowers and seeds.
Plants absorb these nutrients through their roots, and need energy to power up their absorption system. Without oxygen, there is no energy. So, plants need oxygen in order to absorb nutrients and water for them to grow.
Can plants grow without soil?
So far, we’ve seen that the essentials to keep plants alive are: water, carbon dioxide, sunlight, oxygen, and nutrients. Soil is not essential to keep your plant alive.
Soil supports plants to grow upright and expose their leaves to sunlight for photosynthesis to take place. Soil also holds water, oxygen (in the pore spaces), and nutrients.
If you can keep your plant upright and supply its nutrients, it can grow without soil.
How do plants grow in water?
Plants grow in water by first developing roots that can absorb oxygen from water. These roots are different from roots that absorb oxygen from the pore spaces in the soil. They are often referred to as ‘water roots’.
The surface of these roots is coated with a special tissue called aerenchyma. Aerenchyma is a soft tissue containing air spaces that enable your plant to take up oxygen from the water.
That would explain why plants will die in waterlogged soil. Their roots do not have aerenchyma.
Can you grow houseplants in water only?
Depending on the source, water alone contains varying amounts of all the nutrients your plant needs to survive and grow.
These nutrients are present in water as charged particles (ions and anions). The weathering process of rocks adds them to our groundwater (wells and boreholes). Also, dust and gases in the air dissolve in rain as it falls, adding nutrients to it.
I grow my plants in water only without using fertilisers. The leaves turn out smaller than the leaves of plants I grow in nutrient-rich soil, but the plants are healthy nonetheless.
Tip: Rainwater is a rich source of nutrients for plants, even those grown in soil.
What indoor plants can live in water only?
As you’ve probably already noticed, plants differ immensely in how they put up with less-than-ideal conditions such as low light, drought, or intense sunlight. They also differ in their ability to produce roots with aerenchyma to help them survive in water.
Here are some plant genera I’ve successfully grown indoors in water alone for more than one year now: aglaonemas, syngoniums, epipremnums, dracaenas, philodendrons, monsteras, and pandanus.
How to grow and care for your plant in water
To grow plants in water, I like to start the roots afresh. That means I don’t dig up a plant living in soil and place it in water.
Follow these steps and you will be happily growing plants in water in no time.
- Cut the stem or vine of the plant between two nodes as you would when trying to propagate it.
- Remove redundant lower leaves. Remember, the plant is trying to start life afresh with new roots, so don’t overload it with leaves and flowers.
- Place the portion without the roots in water, ensuring one or two nodes are submerged but that no leaves are submerged. Watch out to see new roots develop in a few weeks.
- Change the water every few weeks to refresh the oxygen and nutrient supply. If you notice algae growing in the water, you should change the water and wash the container more often. Algae compete with your plants’ roots for dissolved oxygen.
- Place the plant in a dark vessel to starve the algae of light if the problem persists. Your plant will absorb light if the leaves are exposed.
If you notice a foul odour or air bubbles in the water, this could be due to bacteria breaking down some of your plant’s tissues. Unlike algae, bacteria are invisible to the naked eye. But like algae, they quickly deplete the oxygen supply in the water. You should change the water and wash the container more often. Also, cut off the affected part of the plant to save it from rot.
Good luck!
