Thanks to its lush green fronds and ability to grow well both indoors and out, the Boston fern is one of the most popular container plants. It adds tranquility to porches as you spend long summer days relaxing and enlivens otherwise stale offices during the dark days of winter.
While Boston ferns aren’t especially difficult to care for, their ubiquitous nature means many gardeners have seen or dealt with a yellow, wilting, or generally unhappy plant. That’s why I’m here to share a few tips on how not to kill your Boston fern.
Knowing the plant’s favorite type of light, the ideal temperature, and the best potting mix will get you off on the right foot. Plus, learning some common problems and how to treat them will help you nurse your plant when needed.
Provide the Right Light
Whether you’re keeping your fern inside or outside, providing the ideal light is key. These ferns grow wildly in the understories of forests, so your goal is to provide an environment that mimics their native home.
Ideally, you’ll place your plant in a spot that receives two to eight hours of bright indirect light each day. If your fern is outside, set in under the dappled light of larger plants or a slatted fence. It’s okay if it’s the shade for most of the day, but make sure it receives at least a few hours of dappled or filtered light.
You can place indoor ferns a few feet away from an east-facing or west-facing window or near a south-facing window covered with a sheer curtain. You can even place them in a dim room with light from a small window. Remember to keep the fern out of direct light, especially in the hot summer months. You should also notice how the light shifts through the seasons and move your plant as necessary.
Too much bright light can cause the fronds to develop dry, brown tips, while too little light can lead to stunted growth and discolored plants. As long as your Boston fern is out of direct light and total darkness, it will be easy not to kill it.
Irrigate Only When Necessary
One of the trickiest parts of growing houseplants is knowing when to water them. Irrigation is a crucial consideration if you don’t want to kill your Boston fern. Since they don’t receive rainwater, it’s up to you to provide them with all the moisture they need.
If you water too much, the plants can develop root rot and have difficulties taking up water and nutrients. But if you water too little, the leaves will become dry, and the plant won’t be able to complete processes like photosynthesis and cell division.
So, how do you know when it’s time to irrigate? One way is to check the soil moisture with your finger. When the top inch of the soil feels dry, add water until the soil is moist.
Since Boston ferns are often densely packed in their pots, it’s sometimes difficult to get a finger into the soil. Don’t worry; you can also check the moisture level by picking up the pot. When it begins to feel light, go ahead and irrigate.
Like with all plants, it’s important to notice how irrigation requirements change with the environment and seasons. You can expect to irrigate your plant more when it’s in a hot and sunny area than when it’s in a cool spot. Additionally, expect to water less in the winter.
Tap water is often okay to use. However, if you have hard water, consider using rainwater or filtered water to prevent the buildup of salts.
Choose the Ideal Soil Mix
Since these beautiful ferns spend their lives in pots, choosing a suitable soil mix is crucial for keeping them alive. If you buy a fern from a nursery or other store, it’s probably fine to keep its current pot and soil. However, when it comes time to repot your fern or move it to a larger container, ensure you choose a good mix.
In order to avoid waterlogging and root rot that could kill them, Boston ferns need a soil mix that’s high in organic matter and well-draining. Mixes made from peat moss or coco coir, perlite, and a bit of compost work well. Many pre-mixed houseplant soils with a base of peat moss or coco coir often work well.
Keep Humidity in Mind
These plants are native to tropical regions and love humid conditions. That’s why they often look so happy when they spend the summer outdoors on the humid East Coast.
When you move the fern indoors, it will likely be exposed to lower humidity. You can keep your plant happy by placing it in a naturally humid area like a bathroom or kitchen. However, most areas will work well as long as your plant is away from drying heat sources like air vents and fireplaces.
There’s no need to mist your plant. While this increases moisture on the fronds, it only increases the humidity for a few minutes and can lead to fungal diseases. If you’re really worried about dry air, add a humidifier to your home.
Watch Out for Crispy Leaf Tips
Crunchy brown frond tips could indicate numerous problems with your fern. There’s no need to panic, but you should take some steps to figure out what’s leading to the discoloration.
One possibility is that the air is too dry. Make sure to keep your fern away from any drafts and direct heat sources. You can also move the plant to a more humid area of your home, like a bathroom.
There could also be issues with the salts and nutrients in the soil. Using hard water can lead to a buildup of salts and stress the plants. Switching to rainwater or filtered water can solve this problem. Overfertilizing can also lead to brown tips, so only fertilize with a low-dose fertilizer once in the spring.
Look Out for Pests
Tiny pests like aphids, spider mites, mealy bugs, whiteflies, and thrips can all attack Boston ferns, sometimes killing them. These critters pierce the fronds and drink the plant’s sap, leading to small yellow dots or entirely discolored leaves. However, controlling these pests before they boom in population can prevent severe damage.
These pests often enter your home on already infected plants, so make sure to check each plant before you bring it indoors. The same thing applies when you move an outdoor plant indoors.
You should also spend a few minutes each week checking for any of these unwanted visitors. If you spot a few pests, you can wipe them off with a soapy rag or wash them off with a blast of water. Another option is to spray the pests with neem oil or insecticidal soap. Continue to check your plant for pests and retreat as necessary.
Don’t Assume Drooping Leaves Means Dry Soil
Many gardeners assume wilting or dropping fronds indicate that your houseplant needs more water. However, this isn’t always the case. Lackluster fronds often indicate too much water or not enough sunshine.
While Boston ferns like lots of humidity, they’re sensitive to wet soil. If the roots and crown of the fern remain moist, the fern can have difficulty taking up water, leading to drooping fronds. Remember to use a well-draining soil mix and only water when the top inch is dry.
Another possibility is not enough light. Although these ferns don’t need lots of sunshine, they will suffer if they don’t receive at least a few hours of indirect light each day.
