However, the time of year you choose to plant out your ferns can make or break their overall health. The best time to plant ferns outdoors depends on your climate. However, spring and fall planting is often better than summer planting, as there are usually fewer weather extremes in these seasons. If you live in a location that has wet or freezing winters, plant your ferns in the spring. However, if you live in a particularly hot climate, a fall planting is best.