Curling leaves on a ZZ plant can be rather alarming for a grower, especially if they do not know what has caused the problem! If you notice your ZZ plant’s leaves curling, take a deep breath – your plant just probably needs a sip of water.
Underwatering is the most common issue behind curling leaves, but sometimes it can also be due to other issues like pests, too much sunlight, exposure to cold temperatures, or the plant being rootbound.
Keep reading to understand all the possible causes of leaf curling and discoloration, and what you can do to save your plant.
ZZ plant leaves curling – causes and fixes
Many novice growers make the mistake of underwatering their ZZ plants, in the belief that they can tolerate water scarcity for longer than they actually can. But this neglect comes at a price! Water is a basic requirement for any plant to survive, and if your ZZ is water-deprived, it will start trying to conserve its remaining moisture by curling its leaves to reduce their surface area. You might also notice the plant developing a droopy and sad-looking appearance, which is not the aesthetic you were aiming for in your living space!
- Watering your ZZ plant once every two weeks should suffice. Increase the frequency if the weather is very hot and the soil dries out faster than normal.
- If you are not sure when to water your plant, here is a trick for you: Insert one finger into the soil (about two inches deep) to feel whether it is dry or wet. If it feels dry, then you should water your ZZ. Otherwise, wait for the soil to dry out before watering again.
- Alternatively, use a soil moisture meter if you want convenience and accuracy. This device monitors your soil’s moisture level to help you make an informed watering decision.
- Reduce your watering frequency during winter. Plants go dormant during this season and watering them too often might damage their roots.
2. Too much sunlight
ZZ plants enjoy warm and humid conditions because of their tropical origins. However, they are happier under indirect sunlight. They cannot tolerate the intense heat of full sunlight, and their leaves can easily burn. You will also notice the leaves curl in full sun, as they try to protect themselves from the harmful UV rays.
- Move your ZZ plant away from areas that get direct sunlight, such as south-facing windows. East-facing windows are generally preferable since they provide medium, indirect sunlight without harming the leaves.
- You can also place your plant in shaded spots such as a covered patio to enjoy the filtered sunlight.
- Place a drape or curtain over your window to filter the incoming light if it is too harsh.
- Use artificial grow lights if you cannot find a perfect spot for your ZZ, or when sunlight is not available. Grow lights give you more control over how much light you are giving your plant, without relying on the weather.
3. Cold temperatures
ZZ plants prefer temperatures between 65 and 75 degrees Fahrenheit. If exposed to temperatures below 50 degrees Fahrenheit, the water content of their leaves starts to freeze. So, if you notice your ZZ plant’s leaves curling in very cold weather, it is probably reacting to the temperature drop.
- Add mulch over the plant’s soil. The organic materials act like an insulator to protect the plant’s roots from extreme cold (or heat).
- Protect your plants from cold drafts by placing them away from open windows or doors.
- Limit your watering during the colder seasons. It is also preferable to water your plant in the morning so that it has the entire day to dry. Watering at night keeps the leaves and soil wet for longer, making the plant vulnerable to fungal diseases.
- Use a humidifier to add moisture to the air, especially during the winter season.
4. Pest infestation
Various pests can cause serious damage to your plant’s foliage. Mealybugs, aphids, and thrips, to name a few, feed on the sap of the leaves, stripping away the nutrients needed for plant growth. The plant’s leaves start to curl as it attempts to defend itself from the pests. If your plant’s leaves are curling and you suspect pests, watch out for other symptoms like holes on the leaves, sticky wax or brown spots on the leaves, and the presence of tiny bugs crawling on the foliage. These are sure signs that your ZZ plant is being assaulted by pests.
- Spray the leaves with insecticidal soap to get rid of the bugs.
- Dilute neem oil with water to make a spray solution. Neem oil works great as a natural fungicide without harming your plant.
- You might also dilute alcohol with water and use the solution to wipe the leaves.
- Make sure to quarantine the affected plant to prevent the spread of pests and diseases to your healthy plants.
5. Rootbound issues
A rootbound state means that your ZZ plant has outgrown its container.
ZZs have large underground rhizomes that store nutrients and water to support their growth. This can take a lot of space under the soil as the plant continues to grow and expand. When the pot becomes too small to house all the roots, the plant becomes rootbound and vulnerable to root damage and fungus. Eventually, it will also suffer from water and nutrient uptake issues, leading to problems such as leaf curling. Do not fret – you can correct this problem using the tips below.
- Repot your plant once every two to three years. Make sure the new pot is slightly bigger than the previous one – preferably about two inches larger in diameter.
- Choose a well-draining potting soil that incorporates perlite to improve soil aeration.
- Choose a pot or container with large drainage holes.
- Pots are available in different materials. If you want the soil to dry faster, use a terracotta pot, since plastic containers tend to hold more moisture.
- Avoid repotting your plants during the winter season. Instead, do this in spring or summer to give your plant time to acclimatize to its new pot before it goes dormant.
- Prune off damaged leaves and stems while repotting, to encourage new growth.
Wrapping it up
Curling leaves is one of a plant’s natural defense mechanisms against stress. The leading cause is a lack of water, but other factors such as pests, a rootbound state, extreme temperatures, and too much sunlight are also possible contributors. Try to understand the specific issue so you can take the appropriate measures to bring your plant’s gorgeous leaves back to life.
Image: istockphoto.com / Bogdan Kurylo