Cast iron plants (Aspidistra elatior) are popular evergreen houseplants famed for their large, glossy leaves and low maintenance care requirements. Most of the time, these leaves are a wonderful dark green. However, cast iron plant leaves may sometimes turn yellow due to environmental stress, pest issues, or lack of care. In this article, I’ll look at ten common causes of yellowing leaves on cast iron plants and how to fix them.
- 10 Common Causes of Yellowing Leaves on Cast Iron Plants
- About Cast Iron Plants
- Yellow Leaves on Cast Iron Plants FAQs
10 Common Causes of Yellowing Leaves on Cast Iron Plants:
Overwatering is the most common cause of cast iron plants developing yellow leaves. Cast iron plants need to dry out quite a bit before being watered.
If you overwater your cast iron plant, the soil becomes waterlogged. This leads to severe problems like root rot, which can cause drooping or yellowing leaves. Check whether the soil feels waterlogged and if the roots are brown, mushy, or smelly.
Let the top few inches of soil dry out before watering again. You can also replace the soil with a loose mix that provides better drainage.
Cast iron plants may also turn yellow if the plant isn’t getting enough water. The leaves may also start curling or developing brown tips. Underwatering is a common problem during hot, dry summers.
If the soil is completely dry and pulls away from the edges of the pot, your cast iron plant needs watering. To rehydrate your plant, place its nursery pot in a shallow tray of water for half an hour or so. Your plant will soak up the water it needs to recover.
3) Too Much Sunlight
Cast iron plants grow best in bright, indirect light but can also thrive in low-light conditions. However, cast iron plants are sensitive to bright, direct sunlight. If your cast iron plant gets too much sun, it may develop yellow, faded, or burnt leaves.
To protect cast iron plants from direct sunlight, position them approximately 3 feet away from an east or southeast-facing window. If necessary, filter some of the light using blinds or sheer curtains. Cast iron plants also grow well in north-facing rooms.
4) Not Enough Sunlight
Cast iron plants may also develop yellow leaves if they don’t get enough sunlight. Although this is a rare occurrence, it affects your plant’s ability to produce healthy new growth due to impaired photosynthesis. Even though cast iron plants grow well in low light, they still need approximately 3 hours of sun daily.
Let cast iron plants soak up a few hours of morning sunlight every day. Morning sunlight is less intense than afternoon sunlight and won’t burn the leaves.
5) Wrong Type of Soil
Cast iron plants may end up with yellow leaves if they’re left growing in the wrong type of soil. Cast iron plants need loose, well-draining soils that still hold some nutrients. These slow-growing plants also spend several years in the same pot, so the correct soil type is crucial.
If the soil doesn’t offer enough drainage, it can become waterlogged. This causes fungal problems like root rot. To provide plenty of drainage and nutrients, use a mix of indoor potting mix and coarse sand or perlite.
6) Lack of Nutrients
If cast iron plants don’t get enough nutrients, their lush green leaves may turn yellow. Cast iron plants need plenty of nutrients to produce healthy new leaves. A lack of nutrients can severely affect growth.
Use fertilizer to top up the nutrients in the soil. Fertilize cast iron plants once a month during the growing season. Organic liquid fertilizers with a balanced NPK ratio are the best choices. Always dilute liquid fertilizers according to the instructions on the packet before applying.
7) Too Much Fertilizer
Although cast iron plants need plenty of nutrients, too much fertilizer can actually cause problems. Fertilizers use strong chemicals and salts that can build up in the soil over time. These strong ingredients can cause the leaves of your cast iron plant to turn yellow.
Other symptoms of over-fertilizing include curling leaves with brown tips. You may also notice white patches in the soil. These are excess salts that build up in the soil over time.
8) Incorrect Temperature or Humidity
Cast iron plants may also develop yellow leaves if exposed to the wrong temperature or humidity levels. Plus, they like warm temperatures between 65 and 85ºF. Cast iron plants also prefer moderate humidity levels of approximately 40%.
These levels may be incorrect if the leaves are curling, drooping, and turning yellow. Keep your cast iron plant away from cold or dry drafts caused by air vents, open windows, or heaters. Use a humidifier or pebble tray to increase ambient humidity.
9) Diseases or Pests
Diseases and pests can also turn cast iron plant leaves yellow. This is especially true if your cast iron plant is being attacked by sap-sucking pests like aphids. These pests cause new growth to look weak, stunted, and occasionally yellow.
Eliminate pests like aphids using insecticidal soap or horticultural oils like neem oil. You can get rid of diseases and fungal infections using organic copper fungicides. Providing the right care is the best way to protect cast iron plants from pests and diseases.
10) Transplant Shock
Cast iron plants may develop yellow leaves as a result of transplant shock. Cast iron plants are slow-growing houseplants. As such, they usually need repotting every two or three years.
If cast iron plants are repotted too frequently, they may suffer from transplant shock. This causes a few leaves to turn yellow or look unhealthy. When repotting cast iron plants, only go up one pot size and keep the soil moist until the plant acclimatizes.
About Cast Iron Plants
Cast iron plants (Aspidistra elatior) are members of the asparagus family (Asparagaceae). These evergreen plants are native to parts of Eastern Asia, including Japan and Taiwan. While frequently grown as houseplants, cast iron plants can also be grown outdoors in USDA Zones 7 to 11.
Cast iron plants grow and spread via underground rhizomes. These perennials are known for their large, glossy blade-like leaves. Although these leaves are usually dark green, different types of cast iron plants may have light green or variegated leaves.
Also known as bar room plants, cast iron plants offer a host of uses and benefits and grow best in indirect light or partial shade. These popular houseplants can tolerate neglect and require loose, well-draining soils.
Yellow Leaves on Cast Iron Plants FAQs
Yellowing Leaves on Cast Iron Plants – Wrapping Up
It can be annoying when the glossy green leaves of your cast iron plant start turning yellow. This is usually caused by overwatering or exposure to too much bright sunlight. Other causes include a lack of nutrients or incorrect temperature. Once leaves have turned yellow, remove them, as they won’t recover.
Edd is a budding content writer and gardener living in the United Kingdom. He has a bachelor's degree in Creative and Professional Writing and has written for several gardening publications online. He is passionate about nature and sustainability with a focus on gardening and wildlife.