The Boston Fern (Nephrolepis exaltata) is a popular houseplant known for its cascade of lush, green fronds. Native to tropical and subtropical regions, it naturally thrives in warm, humid forest floors. Moving your potted fern outdoors during warmer months provides ideal conditions for vigorous growth often difficult to replicate indoors. This seasonal retreat allows the fern to benefit from increased air circulation and natural light exposure.
Selecting the Ideal Outdoor Environment
Proper placement is the most important factor for successfully moving a Boston Fern outside. Because of its tropical origins, the fern’s delicate fronds are sensitive to harsh, direct sunlight. Direct exposure, especially during midday, will quickly scorch the foliage, resulting in brown tips and a decline in health.
The fern should be situated in a spot that receives filtered light or deep shade, such as beneath a dense tree canopy, on a covered porch, or against a north-facing wall. This placement mimics the dappled light it receives in a forest understory. Introduce the fern to its new location gradually, a process called acclimation, by starting with a couple of hours of outdoor exposure daily over a seven-to-ten-day period.
Temperature is a primary concern, as the Boston Fern prefers a consistent range between 60°F and 75°F. While it can tolerate slightly cooler temperatures, the minimum threshold is around 50°F; temperatures consistently below this point can cause damage. Strong winds must also be avoided, as rapid air movement increases the rate of moisture loss from the fronds, leading to browning and brittleness.
Managing Hydration and Nutrition Needs
Outdoor conditions significantly alter the fern’s watering needs, as increased heat and air circulation cause the soil to dry out faster than indoors. The soil should be kept consistently moist, but never saturated. A thorough watering is needed when the top inch of potting mix feels dry to the touch. During peak summer heat, especially in a hanging basket, this may necessitate daily watering.
Replicating the high humidity of its native habitat is also a factor in maintaining healthy, vibrant fronds. This can be achieved by placing the fern among a cluster of other plants, which create a humid microclimate. Alternatively, setting the pot on a saucer filled with pebbles and a shallow layer of water will increase local humidity as the water evaporates, ensuring the pot remains above the waterline.
During the active growing season from spring through early fall, the fern benefits from regular, weak nutrient supplementation. Ferns are not heavy feeders, so apply a liquid, balanced, water-soluble fertilizer at a diluted strength, typically half the recommended rate. This diluted feeding should be done every four to six weeks to encourage lush growth without risking fertilizer burn.
Protecting Against Outdoor Threats
Moving a fern outside exposes it to a new range of potential pests uncommon indoors. Chewing pests, such as slugs, snails, and caterpillars, can cause significant damage, leaving ragged edges or holes in the fronds. Inspecting the plant regularly and manually removing any visible pests is the simplest method of control.
Scale insects and mealybugs, which may transfer from other garden plants, can also infest the fern, often clustering on the undersides of the fronds. If an infestation is detected, treating the plant with an insecticidal soap or horticultural oil can manage the issue. Sudden, heavy downpours are also a threat, as prolonged saturation can lead to waterlogged soil and root issues. Move the fern under shelter during severe storms as a proactive measure.
Preparing for the Return Indoors
The transition from outside to inside must be planned well in advance of the first autumn frost. Move the plant back indoors when nighttime temperatures consistently begin to drop below 55°F. Bringing the fern inside too late risks exposure to damaging cold temperatures that can shock the plant.
Before the move, a thorough pest inspection and preventative treatment are necessary to protect all other indoor plants. This preparation includes hosing down the entire fern, paying close attention to the undersides of the fronds to dislodge any hitchhiking insects. A final treatment with insecticidal soap or a wipe-down of the fronds with a diluted alcohol solution can eradicate any remaining hidden pests.
Trim back any leggy, yellowed, or damaged fronds to tidy the plant before bringing it inside. Once situated in its indoor location, which should offer bright, indirect light, the fern’s care routine must change. Watering should be significantly reduced, allowing the soil to dry out more completely between applications. All fertilization must cease to allow the fern to enter its winter rest period.