Coco liners are a popular choice for gardeners seeking a functional and natural aesthetic for container displays, such as wire hanging baskets or window boxes. Derived from the outer husks of coconuts, these liners serve as a permeable boundary between the potting mix and the open-wire frame. The suitability of coco liners for plant health depends on understanding their composition and actively managing their unique traits.
Inherent Properties of Coco Coir
Coco coir is the fibrous husk extracted from coconuts, making it a sustainable, biodegradable byproduct of the coconut industry. This material possesses a highly porous, open structure that allows for significant air and water movement. Coco coir maintains a near-neutral pH, typically ranging between 5.5 and 7.0, which is generally favorable for most common garden plants.
Coir includes small amounts of naturally occurring potassium and phosphorus, though it is not considered a nutrient-rich medium. Due to its high Cation Exchange Capacity (CEC), coco coir holds onto positively charged nutrient ions, which aids nutrient delivery. However, this capacity also means the raw material can bind specific elements like calcium and magnesium, necessitating proper preparation before use.
Advantages for Container Gardening
The porous nature of the liners translates directly into superior conditions for root development. This structure ensures excellent aeration, which is the movement of oxygen to the roots. Robust oxygen supply is crucial for metabolic processes and helps prevent anaerobic conditions that lead to issues like root rot, which often occurs in standard pots with compacted soil.
The open weave also provides exceptional drainage, allowing excess water to flow freely and preventing the potting mix from becoming saturated. While excess water drains quickly, the fibers possess a high water-holding capacity, retaining moisture for plant uptake. This combination of drainage and retention maintains a desirable balance of air and moisture in the root zone, promoting vigorous growth. The liners also offer a natural, earthy appearance that enhances the aesthetic appeal of container displays.
Managing the Critical Drawbacks
The most significant challenge when using coco liners is the problem of rapid drying, especially in conditions of high heat, wind, or low humidity. The exposed sides of the porous liner allow for high rates of evaporation from the entire surface area, causing the potting mix to dry out much faster than in solid-walled containers. This often requires gardeners to water hanging baskets once or even twice daily during the peak summer months to prevent plant stress.
To mitigate this frequent watering requirement, one effective technique is to line the inside of the coco material with a thin sheet of plastic or a biodegradable liner. This internal barrier reduces water loss through the sides while a small hole cut in the bottom of the plastic still allows for necessary drainage. Alternatively, water-retaining additives such as polymer moisture crystals or highly absorbent materials can be mixed into the potting medium to boost the overall water-holding capacity of the soil.
Nutrient Management
Another consideration is nutrient management, as the frequent watering needed to keep the coir moist can lead to significant nutrient leaching. When water constantly flows through the open structure, it washes away dissolved nutrients, requiring a more active feeding strategy. Gardeners should use slow-release granular fertilizers mixed into the soil at planting or commit to more frequent applications of liquid fertilizer to ensure a consistent supply of nutrients. Proper preparation of the coir, often called “buffering,” is also necessary to prevent the material from binding essential calcium and magnesium, which can lead to early deficiencies.