Can You Keep Ferns Alive in the Winter? | Indoor Overwintering Steps

Yes, you can keep ferns alive through winter by moving them indoors before the first frost and providing bright indirect light, humidity, and reduced watering through their dormant season.

Porch and Boston ferns turn brown the first night temperatures drop below freezing. But a fern that gets moved indoors before that cold snap can survive the winter and go back outside green in spring. The process is straightforward — one weekend of work, then monthly maintenance until warm weather returns. Here is how to pull it off without turning your fern into a brown mess by January.

When To Bring A Fern Inside For Winter

The window for moving ferns indoors closes when overnight temperatures hit the mid-50s °F. Growth slows below 50°F and freezing kills the foliage outright. Move the plant in well before your area’s first frost date — that window varies by region, but the sign to watch for is any forecast predicting overnight lows in the 50–55°F range.

If you already missed that window and the fronds are brown, check the root crown. A firm center with some green around the base means the fern can regrow from the crown once placed in proper indoor conditions. If the crown is mushy or fully dried out, the plant likely won’t recover.

Preparing A Fern For The Indoor Move

Rinse And Inspect For Pests

Outdoor ferns carry insects — aphids, spider mites, mealybugs — that will spread to houseplants if not removed before the move. Hose down the entire plant, including the undersides of fronds, to knock off dust and bugs. Inspect the crown and leaf axils closely; treat any visible infestation with insecticidal soap before bringing the pot indoors.

Trim Damaged Fronds

Cut away brown, dead, or yellowing fronds at the base. Light pruning reduces the plant’s water and nutrient needs during the stress of relocation and makes room for new growth in spring. Leave healthy green fronds in place — the fern needs them for photosynthesis even in its slower winter state.

Check For Root Bound Pots

If roots are circling the bottom of the pot or pushing through drainage holes, repot into a container one size larger. Use potting mix with good drainage and ensure the new pot has holes in the bottom — standing water in winter is the fastest way to kill an overwintered fern.

Where To Put A Fern Indoors For Winter

Fern Winter Care: Watering, Humidity, And Fertilizer

How Often To Water An Indoor Fern In Winter

Water less than you think. Most winter fern deaths come from overwatering, not underwatering. Check the top inch of soil with your finger — if it feels dry, water thoroughly until it runs through the drainage holes. If it still feels damp, wait. In a cool basement that might mean watering once a month; in a warm living room with bright light it might be once a week. No schedule fits every setup, so let the soil dryness be your guide.

How To Keep Humidity High Enough

Heated indoor air drops below 30% humidity in winter — too dry for ferns. A cool-mist humidifier placed near the fern is the most effective solution. A pebble tray with water under the pot works well too, as long as the pot sits above the water line and not in it. Grouping ferns with other houseplants also lifts local humidity slightly.

Do Not Fertilize During Winter

Ferns stop active growth in winter (or slow to nearly nothing) and cannot use fertilizer during that rest period. Applying it can burn the roots or encourage weak, leggy growth. Skip all fertilizer from October through February and resume in early spring when new fronds appear.

Overwintering Ferns In A Basement Or Garage

Some gardeners prefer to overwinter ferns in a cool, dark space where they go fully dormant. This works if the space stays above freezing — a garage or basement that holds at 40–55°F can keep a fern alive with almost no care. Give the plant a small amount of indirect light if possible (a basement window or a single grow light), and water roughly once a month — just enough to keep the crown from drying out completely. The fern will look half-dead but will green back up when moved to light and warmth in spring.

How To Transition A Fern Back Outside In Spring

Moving a fern straight from indoors to full sun is a shock that browns every frond in two days. A gradual acclimation over 2–3 weeks lets the foliage adjust. Start when overnight temperatures stay reliably above 50°F. Resume normal watering and start fertilizing at half-strength once new fronds are visible.

Fixin’ A Frustrating Fern: Common Winter Failure Modes

• Brown frond tips: Usually dry air or too much direct sun. Move the fern away from the window and add a pebble tray or humidifier.
• Yellow, mushy fronds: Overwatering. Let the soil dry more between waterings and check that the pot drains freely.
• Dropping fronds: Cold draft or sudden temperature change. Move the fern away from exterior doors, leaky windows, or heat vents.
• No new growth by April: Normal for a cool-overwintered fern. Move to brighter light and slightly warmer temperatures; new fiddleheads will appear within two weeks.
• White or webby material on fronds: Spider mites from dry air. Rinse the plant in the shower and increase humidity.

Keep It Alive Checklist

Bring the fern inside before the first cold snap, rinse off bugs and dead fronds, set it in a spot with indirect light and no drafts, water only when the top inch of soil is dry, skip fertilizer until spring, and acclimate it back outside slowly over a few weeks. That is the entire process — ferns are not delicate about overwintering; they just need the basic conditions listed above.