The nutrients for plants are usually provided through the use of a good soil, but what about growing plants in water? Growing plants in water, whether houseplants, outdoor plants or an indoor herb garden, is an interesting activity for the novice gardener (great for kids!), people with limited space, and those who are plant watering-challenged. This method for growing plants is not only low-maintenance, but also disease and pest resistant.
Growing plants in water without soil is most commonly done as a way to propagate a plant using cuttings. But there are plants that can grow in water alone, some of which are listed at the end of this article. Growing houseplants in water is also known as hydroponic farming, although when commercially grown in this manner, farmers use a more specific cocktail of water to liquid nutrition instead of soil.
Growing Plants in Water Without Soil
Soil provides plants with drainage, aeration, moisture retention, support and nutrition, so how can a plant grow in only water? Generally, plants need more than what water alone can give, but water is great for propagating many types of plants.
A lot of plant varieties can be rooted in water, but with some the roots eventually become fibrous and the emerging green foliage gets pale and spindly. These are signs that the plant needs more. In other words it’s time to plant the start in soil.
Houseplants grown in water may be a slower method than soil-based planting, but your indoor water garden will remain lush for a lengthy period of time.
How to Propagate Plants in Water
Growing plants in water is often a method of propagation using clippings that can develop roots while submerged. To start new plants from existing plants, cut a 3-4 inch (8-10 cm) stem from the parent plant. When you make your cut, be sure to leave at least one node at the point where the leaf emerges from the stem, and some leaves at the end. Put the cutting in a clean container filled with fresh tap water. Make sure no leaves are submerged.
Place the cuttings in an area of bright but not direct sunlight and away from any drafts at a room temperature of around 70 F (21 C).
Change the water at least twice a week to keep it clean and oxygenated. Roots will generally appear within 3-4 weeks. When the roots are an inch or two (2.5 or 5 cm) long, remove the cutting from the water and plant it in a well-draining planting medium.
Plants Grown in Water vs Soil
There are many plants that can be grown in water as long as their requirements are met. Plants need light as well as nutrients, support, consistent temperatures, water and oxygen, all of which can be provided when growing them in water.
The water container provides the support, nutrients can be given via liquid fertilizer, and the water not only irrigates the growing plant but also provides essential minerals and oxygen. Another plus for plants grown indoors is that they enjoy a more consistent temperature.
You can grow plants in water either by using cuttings as described above, or by using a plant that’s already rooted in soil. If you use a soil-rooted plant, be sure to wash all the dirt off the roots before submerging it.
Caring for Plants Growing in Water
You can use pretty much any type of container, from vase to glass jar to old yogurt container. But clear or colored glass looks the prettiest and allows you to keep tabs on the root system as well as the cleanliness of the water.
Consider the possibility of removing the plant if the neck of your container is small so that you'll need to break the plant to get it out. Most any type of waterproof receptacle will work except those made of copper, brass or lead. Metals may corrode when reacting to fertilizer and can cause plant damage.
How to Start
Once you have picked the appropriate container, fill it three-quarters full with florist’s foam (the best bet), crumbled Styrofoam, gravel, pearl chips, pebbles, sand, marbles, beads or any similar material. Add a pinch of powdered or small piece of charcoal to keep the water clear and clean smelling.
The amount of light the plant gets will affect the quality of the water. Try to choose low-light plants to grow in water, and keep them in bright indirect light. If your plant needs direct sun, chances are high the water will become cloudy with bacteria that also thrive with sun.
Algae and Fertilizer
A dark or opaque container will help to prevent algae formation. It won’t matter to the plant, however, which uses its leaves – not roots – to photosynthesize. If you do get algae, either remove the plant, clean the container thoroughly and replace the water and plant.
Change the water every 2 to 4 weeks, and fertilize your plant every 4 to 6 weeks. You can use a liquid fertilizer or one formulated for use on hydroponic plants. Use according to the manufacturer’s instructions.
What Type of Water to Use
Rain water is a great option for growing plants. Bottled water is fine as long as it isn’t too low in minerals. Most types of water are suitable for growing plants but there are some exceptions.
Well water isn’t always of good quality. Reverse osmosis water is also not a good choice. It is devoid of nutrients your plant needs and will only starve the plant.
Tap water works well, but if it’s high in chlorine or chloramine it should be allowed to sit at room temperature for 24 hours before use. This will allow the chemicals to naturally disperse, or you can purchase a dechlorinator.
Good Plants To Grow in Water
Here’s a list of some good options for plants you can grow in water:
- Chinese evergreen (Aglaonemas)
- Chinese Evergreen
- Dumbcane (Dieffenbachia)
- English ivy
- Inch Plant
- Lucky Bamboo
- Mini Monstera (Rhaphidophora Tetrasperma)
- Peace Lily
- Prayer Plant
- Spider Plan
- Sweet Potato Vine
- Wax plant
It’s a great idea to experiment with these plants. If they don’t grow successfully in water, you’ve only lost a cutting or two. Hanging or creeping plants such as vines are often the easiest to root in a water environment, but rooted plants may be used as well.
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Amy Grant has been gardening for 30 years and writing for 15. A professional chef and caterer, Amy's area of expertise is culinary gardening.