How Often Should You Add Miracle-Gro to Ferns?

Green leaves signal the fern hasn't gotten too much fertilizer.

Green leaves signal the fern hasn't gotten too much fertilizer.

It's easy to burn sensitive ferns if you give them too much chemical fertilizer. In general, Miracle-Gro fertilizers are unlikely to burn plants if you follow the label directions carefully. Use all fertilizers sparingly on ferns and mix them using the lowest rate recommended on the label. After fertilizing, watch for signs of over-fertilization such as dry, dead leaf tips.

Growing Ferns

Outdoor ferns thrive in moist areas with well-draining soil and plenty of shade. This includes Western sword fern (Polystichum munitumthrive), which grows outdoors in U.S. Department of Agriculture plant hardiness zones 5 through 9. Before planting ferns, add organic matter to clay soils to increase drainage and to sandy soils so they retain moisture better. Houseplant ferns, such as Boston fern (Nephrolepis exaltata), which also grows outdoors in USDA zones 8 through 11, can be grown in bright, filtered light near a window. Ferns grown as houseplants should generally be watered before the soil dries out and kept humid.

Fern Fertilizer

Outdoor ferns can be fertilized in spring, preferably with a slow-release plant food such as Miracle-Gro Shake 'n Feed. If plants are divided or transplanted in the fall, there is no need to add fertilizer to the soil at the same time. Watch your ferns for signs of fronds turning brown along the edges. If this happens, reduce fertilizer frequency and amounts. Increased watering can help flush out extra chemicals if the plants start to look burned.

Fertilizing In The Garden

When using slow-release fertilizers, ferns grown outside in the garden only need to be fertilized once a year in spring. Miracle-Gro Shake 'n Feed is a granular, slow-release fertilizer that should be applied evenly to the soil at the rate of 1 tablespoon per 1 square foot, then worked into the top 1 to 3 inches of soil and watered in. Alternately, water-soluble Miracle-Gro can be mixed in a watering can at a rate of 1 tablespoon per gallon of water. One gallon will feed 10 square feet of soil and can be applied every seven to 14 days.

Fertilizing Indoor Ferns

If the leaves of houseplant ferns start to look pale and lose color, it is a sign the plant needs more fertilizer. Plants that turn brown and die at the tips of the fronds are being over-fertilized. All-purpose Miracle-Gro can be used for houseplants at the rate of 1/2 teaspoon per 1 gallon of water and applied to the soil every two weeks. Miracle-Gro houseplant food is mixed at a rate of 10 to 20 drops per 1 gallon of water and given to plants with every watering.

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