Q.maiden hair ferns
Should you ever fertilize maidenhair fern? I have several I just started from the older plant that are doing well. I was thinking of using a little time-release fertilizer. These plants are in my house.
It is not recommended to use a potting soil with fertilizer imbedded into it.
You can however use an organic fertilizer at half strength, once a month during it's growing period.
Outdoors in the garden, apply a organic compost to the the soil in the spring.
https://www.gardeningknowhow.com/ornamental/foliage/maidenhair-fern/maidenhair-fern-care.htm