When And How To Fertilize And Water Perennial Ferns

Perennial ferns, often called "hardy ferns," are very easy to grow and care for. There are many fern species and, depending on the species, most will grow well in any average moist to dry, well-drained soil. That said, it's a good idea to know the moisture needs of specific types of perennial ferns you intend to grow. Some prefer a consistently moist soil while others tolerate a drier soil.

Here's a breakdown of what you need to know regarding feeding and watering perennial fern plants...

Feeding Fern Plants

Most perennial ferns do not require fertilizer, however, can benefit from it. In fact, a 1/2-inch layer of aged compost applied in spring, covered by another inch of shredded wood mulch or straw mulch, can provide enough nutrients to maintain healthy fern plants while also helping to hold in moisture. Alternatively, you can apply a light dose of a slow-release fertilizer or a mild organic or natural plant food in spring. Always follow package instructions for fertilizer rates.

Soil pH

Soil pH is a measurement of the alkalinity or acidity of soil, which is measured on a scale of 1-14, with 7 as the neutral mark. Any measurement below 7 indicates acid soil conditions, and anything above 7 indicates alkaline.

While many perennial ferns prefer acidic to neutral soils with a pH of 4 to 7, others prefer a more alkaline soil with a pH of 7 to 8. Most average garden soils fall between a pH range of 6.0 to 7.0. 

If you're unsure about the pH of your soil, or whether or not it's suitable for growing the specific type of perennial fern(s) you intend to grow, it's a good idea to test the soil pH in the planting area. You can quickly test soil pH with an inexpensive soil pH tester probe. To raise the pH (make more alkaline) you can add pelletized limestone to the soil. To lower the pH (make more acid) you can apply Soil Sulfur, Aluminum Sulfate, or Chelated Iron. Adding organic compost to the soil or using compost as mulch can also help to increase acidity and maintain acid soil conditions.

NOTE: Under the description tab on every plant page in Wilson Bros Gardens you'll find the soil pH range the plant will perform best in. 

Watering Perennial Fern Plants

First, a little about soil and drainage. Most ferns like a humus-rich soil that is moist but well-drained. To grow healthy perennial ferns in garden beds or containers good soil drainage is essential. In their native habitat many ferns are found growing on embankments near creeks and streams. So they like a soil that is rich in humus and soft and porous. That means it might be necessary to amend heavy clay soils, which tend to hold a lot of water (especially during winter), with composted manure, chopped leaves, homemade compost, a quality planting mix, or other organic materials. Any site that stays soaking wet isn't good for growing perennial ferns.

When you water your perennial ferns it's best to do so during the morning hours so that water can dry from the leaves before the sun moves to high in the sky. This helps to avoid leaf scald. To avoid foliage disease, avoid watering ferns, or any other plants for that matter, in the late evening or at night.

Watering Ferns At Planting Time 

Immediately after planting deep soak the soil in the planting area, including the rootball, to a depth equal to the height of the root ball.

During the First Active Growth Season

In average garden soil you should not have to water your newly planted Ferns every day. More often than not, this causes soggy soil conditions that can lead to root rot and other harmful plant diseases. Ferns growing in containers might need more frequent watering. In the absence of sufficient rainfall, water only as needed to keep the rootball and surrounding soil damp to moist. Keep in mind that deep soaking less frequently is much better than splashing just a little water on the plants every day. Ferns planted during the winter dormant season, when plants are not actively growing and the evaporation process is much slower, will require much less water. 


In the growing season, most perennial ferns will appreciate supplemental irrigation during drought or dry weather. During dry weather, just keep an eye on your ferns. If you see fronds wilting or curling this could be an indicator your fern plants could use a good deep soaking.

Other Helpful Fern Watering Tips

Rather than watering on a fixed schedule, take weather conditions into consideration and use your fingers to feel the soil. If the soil is damp hold off on watering until it dries some. In containers, provide water when the top inch or so of the soil has become dry. 

When watering with an automated irrigation system it's best to set your timer to water during the early morning hours and not in the late evening or at night. During the first few weeks after planting, check soil moisture often and adjust irrigation time if necessary to keep the soil moist but not constantly wet. 

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