All summer my Fern has been green and beautiful. When the weather changed, I brought it inside for the winter and the leaves began to turn brown and die. People I have talked to say this is normal and I should cut it back for the winter, that it will grow back as beautiful as it was. Is this true? If so, how do I cut it back and do I still water and maintain it over the winter, or is it dormant?
It is best to continue caring for your Boston fern in a well-lit area and giving it lots of humidity and moisture as usual. It will lose some leaves because of the lower light levels indoors, but will recover next spring.
If you can't keep it as a houseplant, it is possible to let it go "dormant" and keep it in a dark place as described in the following article, but this is not true dormancy and is not as healthy for the plant.
https://www.gardeningknowhow.com/houseplants/boston-fern/overwintering-boston-ferns.htm
When to replant into larger container?
If your Boston Ferns growth starts to slow it can be a good indicator of when to repot.
Here is a link with more information.
https://www.gardeningknowhow.com/houseplants/boston-fern/boston-fern-repotting.htm
The temps dropped very low over night. Now my beautiful, big ferns are dark brown. I am sure they were frozen. Is there anything to do for them? I have them inside right now, but now that winter is here, can I save them or should I just discard them?
It does appear the entire plant was effected. Frost damage can continue for a few days or even longer. I would trim away the damaged fronds and wait and see if the plant will send up any new growth.
The roots may still be alive.
Here are some articles with more information.
https://www.gardeningknowhow.com/houseplants/boston-fern/overwintering-boston-ferns.htm
https://www.gardeningknowhow.com/plant-problems/environmental/tips-for-saving-cold-damaged-plants.htm
https://www.gardeningknowhow.com/houseplants/boston-fern/trimming-boston-ferns.htm
I have heard that it is not appropriate to trim/cut off those fronds/runners that grow down underneath the fern itself. Without leaves on them, a stem-like thing that trails under the fern itself. Some are quite delicate and others are clearly stiff stems without leaves. My cat loves to bite those trailing pieces so I would like to trim them so she can't reach them or, at least be less attracted to them. I inherited my fern from my grandmother and my parents were married in front of it in 1937 and it is still going strong and is beautiful. I'd like to have it stay that way. Thanks, Sandra Gillis.
Yes, you can trim these off. They are known as stolons or runners, and they are the plant's attempt at finding a new spot to produce baby plants. If they find soil, they will produce leaves. If you don't want the fern to propagate, you can cut them off.
I brought my fern inside for the winter and the leaves are so long they are brushing the floor. Can I trim it a bit without damaging the plant?
Yes, you can clean up and prune back your Boston Fern.
Here are some links to help you.
https://www.gardeningknowhow.com/houseplants/boston-fern/boston-fern-care.htm
https://www.gardeningknowhow.com/houseplants/boston-fern/boston-fern-misting-needs.htm
https://www.gardeningknowhow.com/houseplants/boston-fern/care-of-unhealthy-boston-ferns.htm
https://www.gardeningknowhow.com/houseplants/boston-fern/trimming-boston-ferns.htm
The new growth on my fern has what looks like white mildew covering it. Can you tell me what to do? Thank you
Without seeing the plant or a few more details it is a bit difficult to say.
New growth can sometimes have a lighter, whitish or light grey fuzzy appearance.
If it is a fungus or insect issue you can easily and safely treat the plant with Neem Oil. Neem Oil is organic and safe for people and pets.
Neem Oil works as both an insecticide and fungicide.
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
Will a Boston fern grow again if you cut it back at the soil line?
Pruning should be done to remove the old fronds or damaged fronds.
It is possible for you to prune the entire plant back, but that is not the recommended method.
https://www.gardeningknowhow.com/houseplants/boston-fern/trimming-boston-ferns.htm
https://www.gardeningknowhow.com/houseplants/boston-fern/boston-fern-outdoors.htm