The Monstera deliciosa, often called the Swiss Cheese Plant, is a popular houseplant prized for its large, fenestrated leaves. This tropical vine is naturally an epiphyte, meaning it grows on other plants in its native rainforest habitat, using them for support. For new plant owners, the absence of the plant’s characteristic aerial roots is a common concern, suggesting the plant may not be thriving indoors. These specialized roots are a natural and necessary adaptation for the Monstera’s climbing growth habit.
What Are Monstera Aerial Roots and Why Are They Needed
Aerial roots are a type of adventitious root, growing directly from the plant’s stem nodes rather than from the underground root ball. These roots serve a dual purpose fundamental to the Monstera’s survival and growth. Their primary function is structural, acting as anchors to attach the climbing vine to tree trunks or other surfaces, allowing the plant to ascend toward brighter light.
As the plant climbs, the aerial roots also absorb supplementary resources. They are designed to collect moisture and nutrients directly from the humid air, rain, and debris accumulated on the host tree’s bark. This additional intake of water and food supports the plant’s massive leaves and vigorous growth. While the soil roots handle the majority of water and nutrient uptake, active aerial roots indicate healthy, naturalistic growth.
Environmental Factors Preventing Growth
The most common reason a Monstera fails to produce aerial roots indoors is a lack of sufficient ambient humidity. In a typical home, relative humidity levels often hover between 30% and 50%, whereas the plant thrives in conditions closer to 60% to 80% humidity. The plant perceives low moisture in the air and thus does not initiate the growth of specialized roots meant to absorb it.
Insufficient light also plays a role, as the plant needs energy from bright, indirect light to fuel all forms of growth, including root development. If the plant is not receiving enough light, its overall growth rate slows, and it may prioritize the established soil root system over developing new aerial roots. A young plant may not grow aerial roots immediately, as it first needs to establish a robust underground root system and reach maturity.
Furthermore, the absence of a vertical structure can prevent the development of these climbing roots. In nature, the Monstera grows toward a tree and uses its aerial roots to latch on. If no support is present, the plant may not perceive the necessity to produce the anchoring roots, particularly if the main stem is not yet mature enough to require external support.
Actionable Steps to Encourage Root Development
To encourage aerial root growth, the most effective step is consistently increasing the localized humidity around the plant. Using a dedicated room humidifier is the most reliable method, aiming to maintain a consistent relative humidity above 60%. Alternatively, you can create a humid microclimate by placing the Monstera’s pot on a pebble tray filled with water, ensuring the pot itself is not submerged.
Providing vertical support will also signal to the plant that it has a surface to climb, which stimulates the anchoring response. A moss pole or a coco coir pole mimics the rough, moist texture of a tree trunk. Keeping the support pole consistently damp by watering it directly will provide a moist environment for the emerging roots to penetrate and attach.
Once a new aerial root begins to emerge, gently guide it toward the moist moss pole or direct it into the soil. Directing the root into the soil allows it to develop into a secondary subterranean root, which can provide additional water and nutrient uptake for the plant. Ensure the plant is receiving bright, indirect light and fertilize regularly with a balanced, diluted nutrient solution to give the plant the resources it needs for root production.