How to Keep Ferns Alive Indoors

Ferns can be difficult to grow indoors. Learn the secrets to successfully growing ferns indoors and keeping them happy and healthy indoors. See care stamps below.

#healthyhouseplants #ferncare #indoorplants #houseplanttips #humidityforplants

Video Transcript

Welcome to HealthyHouseplants.com, where we teach you all about gardening in the great indoors. If you’d like to support our show, please use our Amazon affiliate link below.

Today we’re talking about growing ferns indoors. Ferns can be a little tricky due to their specific requirements, so we’ll dive into how to keep them happy and healthy in your indoor garden.

Ferns are some of the oldest plants on Earth, thriving for at least 300 million years. They’ve adapted to many environments, so you can definitely grow them indoors with the right care. One of the biggest factors is humidity—it’s essential for good fern growth.

If you live in a dry climate, your indoor air may not be ideal. Maidenhair ferns, for instance, can struggle. In that case, terrariums—especially large ones like Wardian cases—can help maintain the right moisture levels. Julie demonstrates a spike moss thriving in a terrarium, while other plants from the same batch have struggled in drier air.

Creating a humid microclimate within a terrarium eliminates the need for misting or moisture trays. If you don’t use a terrarium, you can increase humidity by using a humidity tray (marbles and water), misting regularly, or placing your plant in a humid room like a bathroom with sufficient light.

Another way to increase humidity is by grouping houseplants together. All plants transpire, releasing moisture into the air. This mutual humidity helps all your plants thrive.

A helpful tool is a hygrometer, which measures relative humidity. Julie shows hers reading 50–57%, proving plants actively raise the humidity in their environment.

Lighting is another crucial factor. Indoors, ferns need medium to bright indirect light. Too much sun can cause leaf burn, especially in delicate ferns like maidenhairs. East- or north-facing windows work well, as does full-spectrum lighting, which simulates natural daylight.

Ferns also benefit from organic feeding. They thrive on decaying plant matter (humic acid). Use an organic fertilizer that includes humic acid every 2–4 months—never in winter. Julie recommends her Green Gourmet Houseplant Food.

Watering is key. Keep the soil moist but not soggy. Letting it dry out can lead to leaf loss. Use a moisture meter or finger test to monitor soil moisture. Maidenhair ferns are especially sensitive to dryness.

Always water with warm to tepid water—cold water can shock the roots and lead to root rot or spotting.

Ferns are susceptible to mealybugs, which appear as white cottony pests. Treat them promptly to prevent spread.

Finally, maintain a temperature range between 60°F and 75°F and keep ferns away from drafts.

FAQ's -How to Keep Ferns Alive 101

Frequently Asked Questions About Growing Ferns Indoors

Why is humidity important for indoor ferns?

Ferns require high humidity to thrive. Dry indoor air can cause leaf loss and stunted growth. Using terrariums, humidity trays, and misting can help increase moisture levels.

What kind of light do indoor ferns need?

Ferns do best in medium to bright indirect light. East- or north-facing windows are ideal, and full-spectrum lighting is also highly beneficial.

How often should I water my indoor fern?

Keep the soil consistently moist but not soggy. Water when the top inch of soil is dry. Maidenhair ferns should be watered as soon as the soil surface starts to dry.