I want to save my Boston ferns over the winter. I took them inside my house before the first frost and they already are looking terrible. Is this OK, or should I put them somewhere else that is protected from the cold? - Sheila R.
A: My standard answer (much to many people's disbelief) is to just throw them away if you don't have a greenhouse and just buy more next year. Unless you have a greenhouse, your ferns will look awful in most cases by spring. In the majority of households, ferns simply hate the conditions they are provided. The humidity usually is low and ferns like high humidity.
Depending on where you have them, however, such as on a patio or a porch, you might be able to keep them for a while longer.
If a fern is on a porch with a roof on it, you cannot let a frost fall on it, so if it is on a hanger and it sticks out under an overhang, you at least need to remove it and sit it where it is completely under the overhang. Given this scenario, you could leave a fern out from about 28 to 32 degrees F.
Keep in mind that the direction your porch faces influences how low the temperature can get. If you are facing the northwest, they must go inside if it drops below the 28-32 range. This is the direction of the winter winds.
If your porch has a southwest exposure and the ferns are set against the house, they could stay outside if the temperature drops to around 20. If you have that southwest exposure, there would only be a very few times when you would need to take them inside during the winter. In this case, they would stay looking pretty good the whole season.
For you and anyone else who wants to try to carry them over, here are some things you can try:
- When you need to bring them indoors, leave them in a garage or storage house if space permits and they'll do OK, but not great. If you must take them inside the house, try several things to overcome dry air. You can add humidifiers to your home heating system or buy a self-contained electric humidifier. Not only will a humidifier produce a better environment for your ferns and other plants but it also will provide a healthier atmosphere for you and your family.
- If you don't bother with purchasing a humidifier, put pots of ferns or other plants in saucers or trays filled with gravel and water. This increases the humidity around the plant. Always maintain the water level just below the surface of the gravel so the bottom of the pot won't be standing in water. Some indoor gardeners add charcoal chips to the gravel to help keep the water clean and odor free. For best results, replace the gravel periodically or wash it thoroughly at three-month intervals, or as the algae starts to develop in the water or on the gravel. Sanitation is important in keeping down diseases.
- Many people mist their ferns and other houseplants. Misting is very temporary, but it can help ferns. Mist the plants early in the morning. Apply enough to moisten the fronds well, but not so much that they drip. You can do this several times a day or at least every day, particularly when your heat is running.
Over the years, I have given this advice on leaving ferns outside as long as you can, and many people have experienced better results. Make sure you know what exposure your ferns have on the porch so that you will be able to determine which nights they can stay outside this winter.
Sid Mullis is director for the University of Georgia extension service office for Richmond County. Call him at 821-2349, or send e-mail to firstname.lastname@example.org.