How to Grow Boston Ferns

Boston ferns are the perfect porch plant, as they thrive in lots of indirect light. Morning sun is ideal, as full afternoon sun can burn the fronds. In humid, subtropical areas of Florida (zones 10 to 12), Boston ferns make an attractive mid-height groundcover in areas with dappled shade. They like consistently moist but well-drained soils. Boston ferns grown indoors should be placed near a window, but not in direct sunlight.

Boston ferns will grow as large as the pot allows. Many Boston ferns are sold as hanging baskets in plastic pots, and it’s fine to leave them that way if desired. If you want to plant your Boston fern in different container, though, choose plastic or glazed terra cotta. These types of pots take longer to dry out, making it easier to maintain the plants. It can be difficult to keep a large Boston fern well-watered enough when it is growing in coco coir or an unglazed container, unglazed pot, window box, or hanging basket.

Managing soil moisture is critical to success with Boston ferns. If planning to grow your plant outdoors, fill the bottom 1/3 of the container with Miracle-Gro® Moisture Control® Potting Mix, which absorbs more water than basic potting soil. Place the plant so that the top of the root ball is about 1 inch below the rim of the container (to leave room for watering). Fill in around the root ball with more potting mix, then thoroughly water the plant, let it drain, and move it to its permanent location. 

Repot Boston ferns when the roots have filled the container. If you’re planning to grow Boston ferns indoors, replant in late summer or early fall in Miracle-Gro® Indoor Potting Mix.

Water Boston ferns regularly. A good way to judge whether plants need water is to pick up the container. If it’s light, it needs to be watered; if is heavy, it’s fine. During the summer, ferns growing outdoors often need to be watered in both the morning and the evening. Growth will slow slightly during the winter, but both indoor and outdoor plants still need to be kept evenly moist.

A month after planting, begin to feed your Boston fern for best growth. Use Miracle-Gro® Water Soluble All Purpose Plant Food for larger Boston ferns and those grown outdoors, and Miracle-Gro® Indoor Plant Food for smaller indoor Boston ferns. The amount you use to fertilize your fern will vary depending on its size, so be sure to follow the instructions on the label.

Boston ferns require pruning only when the fronds have dried up and dropped their leaves. If the fern looks ratty, trim back the plant until it is 2 inches tall, water and fertilize, and it will soon begin to grow back out.

Expect some leaf drop when you bring plants indoors for the winter. If the defoliation is extreme, simply cut plants back and allow them to re-grow. Situate Boston ferns indoors in bright, indirect sunlight away from drafty doors and heating vents. Provide as much humidity as possible and carefully monitor the soil to ensure plants stay consistently moist. You can set the plants on pebble trays filled with water, so long as the pot does not sit in standing water. You may also want to use a humidifier or mist the plants with room-temperature tap water.