The Boston Fern (Nephrolepis exaltata) is a favored houseplant, celebrated for its dense, arching fronds that create a lush, cascading effect in a hanging basket. Originating from tropical and subtropical regions, this fern thrives where moisture is consistently available. Maintaining consistent moisture is the most important aspect of its care, which is challenging when the plant is suspended in a container exposed to drying airflow. Gauging the soil’s moisture status, rather than following a rigid calendar schedule, is the foundation for keeping this plant healthy.
Determining Soil Moisture Needs
The frequency of watering is highly variable, depending on factors like pot size, temperature, and the season, so relying on a set schedule is unreliable. Instead, determine your fern’s need for water by checking the moisture level in the top layer of the potting mix. The goal is to keep the soil consistently moist, but never saturated or soggy, aiming for a texture similar to a well-wrung sponge.
The most practical method is the finger test, which involves inserting your index finger one to two inches deep into the soil near the edge of the pot. If the soil at that depth feels dry, crumbly, or warm, it is time to water thoroughly. If it still feels cool and slightly damp, wait another day or two before checking again.
A secondary, effective technique for hanging baskets is the weight test, which is helpful because the dense foliage can make the finger test difficult. Lift the basket shortly after a thorough watering to learn its “heavy” weight. When the basket feels noticeably lighter than this saturated weight, it signals it is time to rehydrate the plant.
Watering Method for Hanging Baskets
When the plant requires water, the application must be thorough to ensure the entire root ball is saturated, preventing dry pockets from forming. Pour water slowly and evenly over the surface of the soil until you see it drain freely from the bottom of the hanging basket. Allowing this runoff ensures that salts and mineral buildup are flushed out of the root zone, which can otherwise cause leaf tip burn.
Hanging baskets, particularly those made of porous materials like coir or unglazed clay, can dry out quickly and become hydrophobic if neglected. If the soil pulls away from the sides of the pot, the root ball has likely become too dry to absorb moisture efficiently. In this situation, take the basket down and submerge the entire pot in a sink or bucket of water for 15 to 20 minutes. This soaking technique allows the dried peat-based mix to fully rehydrate; allow excess water to drain completely before rehanging the basket.
How Environment Influences Frequency
The rate at which a Boston Fern uses water is directly correlated with its immediate environment, causing the watering frequency to fluctuate significantly throughout the year. Higher light exposure, even if indirect, increases the plant’s rate of photosynthesis and transpiration, which draws more moisture from the soil. A fern placed in a bright, indirect light location will dry out faster than one positioned in a shadier spot.
Temperature is a major factor, with warmer air accelerating water loss through both evaporation from the soil and transpiration through the fronds. While Boston Ferns prefer a temperature range of 60°F to 75°F, summer heat or proximity to heat sources will necessitate a much more frequent watering schedule. Conversely, in the winter, when growth slows, the plant’s water needs decrease, and watering frequency should be reduced.
Humidity plays a role, as these ferns are native to humid climates and thrive with relative humidity levels above 50%. Low indoor humidity, common in heated or air-conditioned homes, causes moisture to evaporate rapidly from the fronds and the soil surface. To mitigate this moisture loss, supplement the humidity by placing the hanging basket above a pebble tray filled with water, or by grouping it with other plants to create a beneficial microclimate.
Recognizing Symptoms of Improper Watering
Visual cues from the fronds offer clear signals about the plant’s hydration status, allowing for timely correction of the watering routine. The most common sign of underwatering is the appearance of dry, crispy, and brown tips or edges on the fronds. Severely dehydrated ferns may also show a pale, dull color and a brittle texture, and the entire plant may wilt.
Conversely, overwatering manifests with different symptoms, as the plant may also appear to be wilting. The leaves will turn yellow or develop a mushy texture, and the fronds will droop due to the lack of oxygen reaching the roots. Persistent overwatering leads to root rot, which may be detected by a foul, decaying odor from the soil or the appearance of mold on the soil surface.