There are roughly 200 species of Calathea. These plants tend to have very beautiful foliage, but they can also be very dramatic and frustrating for new plant keepers. Calatheas tend to be fast-growing, but only when given the ideal growing conditions; so how fast do Calatheas grow?
A healthy, well cared for Calathea can usually reach mature size in about a year, at which point it will stop growing upward. Max size in Calatheas is determined by where you grow your plant and what species it is. Some Calatheas only grow to 1.5 feet while others can reach up to 4, and plants that are grown outdoors are usually about twice the size of those grown indoors.
In this article, we will discuss the best care practices you can use to encourage your Calathea to grow in a fast, but healthy way.
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How to Encourage Growth in Your Calathea
Light
One of the most important parts of plant care is lighting. Calatheas prefer bright indirect light, and the more they get the happier they will be.
Calatheas will actually move their leaves throughout the day in an effort to capture more light as the sun moves. Avoid placing them in direct light as this can cause burns to their sensitive leaves.
If you don’t think your plant is getting enough light and you want to increase the amount they receive safely, you can try adding a full-spectrum fluorescent grow bulb near your plant.
Water
Plants can’t live without water, so it makes sense that providing them with the optimal amount and type of water will encourage them to grow quickly.
Unlike many houseplants, Calatheas don’t do well when given tap water. This has to do with some of the minerals that are found in tap water. Instead, provide them with rainwater or filtered water.
Calatheas like to have their soil moist, but not overly wet as they are prone to root rot. Let the top 1-2 inches of soil dry out before each watering. Usually, in spring-fall, you will be watering every 2-5 days, but in the winter it may be as infrequent as every other week.
Soil
When choosing soil for your Calathea, you will want one that retains moisture and is very rich. I recommend using a soil marketed for African violets, or making your own soil with 1 part peat moss, 1 part potting soil, and 1 part perlite. I prefer using FoxFarms brand, but you can use whatever potting soil you prefer.
Fertilizer
Another important part of encouraging plant growth is fertilizer. You will want to fertilize your Calathea once a month in the spring, summer, and fall with a balanced liquid fertilizer mixed to half strength.
If liquid fertilizer seems intimidating, you can also use slow-release pellets. Make sure you don’t over-fertilize in an effort to boost plant growth, as this can cause the roots to burn and even kill the plant.
Humidity
Calatheas like relatively high humidity, preferably between 65-75%. If you are keeping your plant indoors, you will likely need to supplement your plant’s humidity levels.
You can do this by adding a humidifier, providing your plant with a pebble tray, or misting. The two best methods for increasing humidity are humidifiers and pebble trays, but misting can do in a pinch.
Repotting
To encourage your plant to grow, you will want to make sure it is in an appropriately sized pot. A pot that is too large can put your plant at risk of overwatering and root rot.
A pot that is too small can cause your plant to become root-bound and can cause stunted growth. Ideally, you will want your pot to be a few inches larger in diameter than your plant’s root ball, or one size larger than the pot your plant came in.
You will also want to select a pot that has a drainage hole to ensure that excess water flows out of the pot instead of sitting at the bottom and becoming stagnant.
Seasons
One thing you can’t control, but that does have an impact on plant growth is the seasons. Your plant will experience most of its growth in the spring, summer, and fall, and will have little to no growth in the winter. This is completely normal and most plants will go through these seasonal growth changes.
If you want your plant to continue to grow during the winter, you can supplement its light with grow bulbs and keep it in a warm room to simulate summer weather.
Growth Inhibitors
Now that you know how to encourage growth, you may be wondering how to inhibit growth. Maybe you want your plant to fit in a specific space, or maybe you simply want to know what not to do. Here are a few tips to keep your plant small.
Division
The easiest way to make your large plant small is to divide it into multiple smaller plants. You can do this by removing your plant from its pot and dividing the leaves and corresponding root systems with sterilized shears. You can keep all the plants, give away the babies, or sell them online.
Cut the roots
If your plant isn’t large enough to divide, or if you are nervous about dividing your plant, but want to slow its growth, you can cut its roots. Plants that have their roots trimmed back will place their energy into growing new roots instead of growing new leaves or growing taller.
Don’t cut too much of the root system off, but 25-30% will keep your plant from growing upward for a few months. Be sure to use sterilized shears when trimming your roots or you could introduce bacteria into your plant.
Poor care
You don’t want to purposely give your plant poor care, but the reason many Calatheas grow slowly is related to poor care. Not enough water can actually cause your Calathea to grow more roots so that it can find water in your pot. Not enough sunlight can also majorly stunt a plant’s growth.
