How to Care for Castano (Castanospermum) - Expert Tips for Thriving Plants

Castano, or Castanospermum Australe for the full name, has a pretty sad situation… The sad thing about this plant is that it’s a lonely beauty. Castano has only one species in its genus! But still, it’s a beautiful flowering plant from the Fabaceae family, native to the east coast of Australia and the Pacific Islands of Vanuatu and New Caledonia.

In an old book, this plant is also called Moreton Bay “Chestnut tree” or “Bean tree”, but the most known aboriginal name is “Irtalie”. Castanos have beautiful glossy, leathery, dark green pinnate leaves, but the real attraction is its exposed seedpod, which gives it an incredibly exotic look. Outside in the wild, these trees can reach heights of 15 meters. Their height usually stays between 1-2 meters when they are kept indoors.

This tree has a real backstory: Aboriginal people gathered around it because it gave them food. They also used the tree's bark to make fish and animal traps, baskets, and bets. They even used the tree's empty seed pods as toy boats for their children. Such an incredible history, right?

Castanospermum Care: 10 expert tips for growing it successfully

1. Your Castano enjoys lots of natural light. Place it near a window where it will receive bright indirect light. It can tolerate medium-shade spots too!
2. Don't expose it to too much sunlight. Midday sunrays can damage its beautiful leaves. The sun in the morning and evening is not that bad since it is less intense.
3. Be careful not to overwater. Before watering again, wait until half or all of the topsoil has dried. A common problem for Castano owners is root rot caused by overwatering.
4. Be alert for leaf drop. It's normal for Castanospermum Australe to shed its lower leaves as it grows. However, excessive leaf drop may be caused by overwatering, low light, or high temperatures.
5. Make sure you fertilise regularly. It will eventually consume all the soil nutrients and need more for healthy growth. Give it some houseplant fertiliser once a month from spring to summer.
6. Regularly wipe the leaves of your Castano plant with a damp cloth. Over time, dust can gather on the leaves, making it harder for them to soak up light. Plus, clean leaves just look so much brighter and more beautiful!
7. Keep your eye out for pests. Common houseplant pests such as spider mites, aphids, and mealybugs. Act as soon as you spot one!
8. Rotate the plant regularly. Your Castano tends to reach out for the light, which can make it grow unevenly. Occasionally giving it a gentle spin will help it grow evenly.
9. If your Castano gets a bit too tall or starts to stretch out, don't worry - just give it a little haircut. You can make your plant bushier by pinching or cutting back about one-fourth of its size in the spring.
10. Give it a rest period during winter. This is its natural resting time, so go easy on the water and take a break from the fertiliser.

Castano care tips

Light requirements

Castanospermum Australe has a preference for bright but indirect light. As a tough houseplant, it can tolerate some light shade but may become leggy if it's in too dark corner.

Avoid direct sunlight as this may scorch the leaves, and we know that you don’t want to hurt your green friend, right? A little morning or evening sun can be good since it is less intense than the midday sun. Your Castano will appreciate a curtain's shade if the window is super sunny.

Expert tip! You can place your Castano anywhere in the room where it gets the appropriate amount of light, but avoid areas where it may experience drafts or sudden temperature changes, such as near heating or cooling vents, doors, or drafty windows.

Watering

Your Castanospermum loves its soil to be just right - not too wet and not too dry. Be aware that it doesnt like soggy feet at all! It’s best to water it when the soil has slightly dried out. Just feel the soil with your finger or use a water meter to determine soil moisture.

Fertilisation

Your beloved Castano would love a little snack during the growing seasons! She will be pleased if you feed her with our organic PLNTS houseplant fertiliser twice a month during spring and summer. During the winter, it will not be necessary.

Temperature & humidity

Keep the temperature around 18-24°C and humidity levels around 40-50%, and your Castano will be one happy houseplant! Moreover, it can tolerate cold temperatures like 10°C at a push, but avoiding cold droughts is the better option, so keep your lady far from the windows!

Expert tip! Castanospermum will tolerate dry air pretty well, as low as 30%. You might want to raise the humidity for plants if you see any brown leaf edges or leaves start to drop.

Repotting & soil

Your Castanospermum will need a new home once in a while but don't worry, not too often - about every 2-3 years should do it. The exact timing depends on how fast your plant is growing. If you spot many roots sneaking out of the drainage holes, that's your green friend's way of saying it's time for a repot!

Make sure the soil is well-draining and nutrient-rich. We recommend using organic PLNTS houseplant soil to provide all the necessary nutrients for your Castano.

Castano propagation

Sadly for this beauty, the propagation is quite complicated. It’s only possible to propagate Castano by the seeds. The germination requires a temperature between 18°C and 25°C. Afterwards, you can sow them in large, individual tubes and use a special mix of river sand and perlite. You can only start repotting your babies after the first pair of true leaves has formed!

Most common pest on Castano

The most common pests that can affect your Castano are spider mites, aphids, thrips, whitefly and mealybugs. Castano is pretty sensitive to those pesky insects. You can use a magnifying glass to check and prevent your beauty from being infested.

You can find evidence that your plant suffers from a pest with different symptoms: yellow or brown leaves could mean spider mites if you see little webs on your plant. A fluffy white spot on your plant tells you that your Castano is suffering from mealybugs.

Check our PLNTSdoctor page to recognise and eliminate your plant pests! If you are interested in biological pest control, you can look at our blog: ‘Which natural and biological pest control against which pest?’.

Is the Castano toxic for pets or children?

Unfortunately, you need to keep it away from children and pets. Its seeds look like berries and might seem tasty to your kids or pets, but they're actually quite dangerous. Prevent them from having any access to your green cutie, as the seeds are very toxic!

Buy your new Castano at PLNTS.com

At PLNTS.com we have the amazing Castano Magnifico to enlighten your interior, and thanks to this blog, you will be able to impress your guests with your knowledge of this plant! Buy Castano online at PLNTS.com.