How To Properly Overwinter Ferns [Inc. Potted]

Ferns are known to be tropical and subtropical plants that typically grow in zones 8 through 11. However, they're some of the most popular homegrown plants in American gardens. And when wintertime comes, it's best to take certain precautions to ensure that your fern can survive it. So, how do you properly overwinter ferns? We've researched the best way to do so.

Here are the steps to properly overwinter ferns:

  1. Find the ideal location
  2. Remove any plant pests
  3. Re-pot the plant if it's root-bound
  4. Check the plant's hydration level
  5. Prune the plant
  6. Refrain from fertilizing the fern

If you grow ferns indoors, it's important to create the right conditions so that they match their ideal outside conditions as much as possible. Keep in mind that these plants are fairly easy to grow. However, care must be taken to ensure that they can survive the colder months. Continue reading to learn more about how to take care of them after the summer.

Macro closeup of frost ice crystals on brown fern branch leaves plant in morning snow, How To Properly Overwinter Ferns [Inc. Potted]

Steps to Overwinter Your Ferns

All fern varieties may have slightly different overwintering requirements. However, here are a few general steps to take in most cases.

Things you'll need:

  • Pruning shears
  • Plastic bags (for pruned leaves)
  • Rubbing alcohol
  • Watering container

1. Find the ideal location

One of the first things that you'll want to do before overwintering your fern is to find the perfect place to place the plant for the winter dormancy. Remember that the plant prefers cool nighttime temperatures — even if it's potted. Keep in mind that it should not be placed in a location where daytime temperatures will reach over 75 degrees Fahrenheit.

You'll also want to ensure that the average relative humidity is about 45 % to 60%. If you have potted plants, consider moving them to another area such as a cool basement, garage, shed, or outdoor laundry area with access to some natural lighting.

Keep in mind that ferns don't need maximum lighting of full sun during the winter months, as these are slow-growing months. In fact, it can actually be harmful to the plant. So when you're considering a new location, be sure to keep the plants away from southern facing windows to avoid foliage burn. Also, be sure that your new location doesn't drop below 55 degrees Fahrenheit for several days at a time, as this will typically be too cold for the plant. You can use a hygrometer to closely monitor the plant's room temperature and humidity.

Check out this hygrometer on Amazon.

2. Remove any plant pests

If your fern is located outside, it's best to spray it down with an insecticide or a water hose to prevent bringing in any plant pests. You can also rub the plant down with neem oil as well. Afterward, let the fern dry thoroughly outside before giving it another quick inspection and then bring it inside.

Check out this neem oil on Amazon.

3. Re-pot the plant if it's root-bound

If your plants are potted, be sure to inspect the roots in the pot to see if they have become root-bound. And if they have, it's best to move them to a larger pot so that the roots won't become oversaturated with soil in the new temperatures, which can cause them to retain too much moisture. You can also divide or transplant the plants if they've become too big for one pot. Depending on the size, you can split the fern up into two to four new plants.

4. Check the plant's hydration level

During those winter months, you'll still need to water the fern much less. Ferns will still require watering during this time, whether they're grown in pots or outdoors — though a monthly watering will typically suffice. Be sure to monitor the moisture level of the plant's soil every week or two to ensure that it's getting proper hydration — and only water the plant once the soil dries out. Remember, it's best to underwater it than to overwater it during these months.

Check out this watering can on Amazon.

5. Prune the plant

You'll also want to prune the fern before moving it indoors for the winter. When pruning the plant, be sure to leave any new leaves remaining on the plant. 

Read more details about these pruning shears on Amazon.

6. Refrain from fertilizing the fern

This is more of a note than a step. It's best not to fertilize the plants during the winter dormancy, as this is the plant's slow-growing season. Only add fertilizer when you begin to see new shoots sprouting up through the soil. This is the perfect time to resume your regular feeding schedule. With most fern varieties, this occurs around March through April.

Read more details about this fertilizer on Amazon.

How do you take care of indoor ferns in the winter?

The best way to care for indoor ferns is to ensure that they receive some natural light throughout the day. For many varieties, 4-6 hours of partial sunlight should suffice. Also, you'll want to ensure that the temperature setting for your specific fern variety is ideal. This generally averages anywhere from 65 degrees to 72 degrees Fahrenheit.

Also, be sure to keep the fern away from direct drafts of central air, window air conditioning units, or windy doorway areas. You'll need to water the fern as well during this time, but once a month should suffice. Note that it's best to check the plant's moisture level every couple of weeks just to monitor it.

How do you take care of outdoor ferns in the winter?

Horizontal closeup photo of freshly fallen snow on a green tree fern in the NSW New England High Country near Armidale

Depending on where you live, you may want to move the fern to an indoor location. Specifically, if the outdoor temperatures fall below 50 degrees Fahrenheit for several days. Remember that different fern varieties will be more tolerant of colder temperatures than others. And depending on how large the fern has grown, you may want to prune it before you move it (some varieties can grow significantly in the spring and summer months).

However, if you can move your ferns to an indoor location such as a basement or other relatively cooler location for the winter, this may give your plant a stronger chance at surviving the winter months. You'll also want to ensure that the plant receives some filtered daily sunlight.

How do you overwinter a potted fern?

The most important thing to remember when overwintering a potted fern is to place the firm in a location that stays relatively cool — anywhere from 65 to 75 degrees Fahrenheit is perfect. You'll also want to ensure that the fern receives some filtered light throughout the day, but not direct sunlight as it can burn the plant's foliage.

Also, be sure to monitor the hydration level of the plant's soil. Water it only when the soil dries out. If the plant was grown in a garden, it's best to check the plant for pests and eradicate them before bringing it indoors — this can cause the infestation to spread to other plants in your home. Lastly, check the plant roots and leaves. Re-pot the fern if it's become root-bound and prune it if it's become too large to house indoors or contains dead leaves and branches. 

Do ferns need to be cut back for winter?

It depends on the variety and its growth amount. These plants don't absolutely have to be cut back for the winter. However, many gardeners choose to cut them back during their overwintering process. If you prune the plant, it's best not to do so too heavily as the older fronds can help protect the plant during the winter months. They act as an extra layer of insulation from cold temperatures. For this reason, many gardeners opt not to cut them back.

How cold is too cold for ferns?

Macro closeup of frost ice crystals on brown fern branch leaves plant in morning snow, How To Properly Overwinter Ferns [Inc. Potted]

Typically, weather that is below 50 degrees Fahrenheit regularly will be too cold for most fern varieties. Ideal temperatures for most of these plants are usually above between 60 degrees Fahrenheit and 75 degrees Fahrenheit.

What do you do with macho ferns in the winter?

You'll need to tend to them pretty much in the same manner as other varieties. However, macho ferns can tolerate a small change in temperature during the winter months. Though, it's best to bring them indoors and place them in pots, as they'll usually require more care during the winter months. The ferns will only need watering once the soil dries out.

Note that they will require some partial sunlight every day, and fertilizer isn't needed until the winter season is over. Also, the indoor temperature that they're kept in should be moderate and above 50 degrees Fahrenheit on average — above 65 is ideal.

Wrapping Things Up

We hope that this post has helped illustrate how to overwinter ferns in the winter. Keep in mind that the best way to ensure your plant survives the winter is to monitor it every week and check for any changes in its appearance.

Check out our other posts before you go:

Should You Soak Hollyhock Seeds?

Should You Mulch Around Maple Trees?

One comment

  1. […] that the room’s humidity is kept between 45% to 60% and that the temperature remains a cool 65° to 72° Fahrenheit (18° to 22° Celsius), although the ideal temperature will differ between fern […]

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