Baskets of green swinging from porch ceilings are probably what most people think of when they think “ferns.” Those Boston ferns are certainly beautiful (and no shady summertime sitting place is complete without them), but theres a wide world of ferns beyond Bostons. Ferns are wonderful in-ground garden and container plants because they have a lacy texture not offered by many other foliage plants. And since contrast is the spice of life, pairing ferns with solid-leafed plants such as hostas, brunneras, and coral bells instantly results in a professional-looking design, no matter how new you are to gardening. On the whole, ferns are fairly un-fussy plants, too, and everyone loves low-maintenance.
Growing ferns in pots can be highly rewarding if you get the soil conditions right. With their graceful, arching fronds and lush green texture, ferns make excellent additions to container gardens. But getting them to thrive requires creating a specialized potting mix tailored to their needs.
So what exactly is the best potting soil for ferns in pots? This comprehensive guide will overview the ideal ingredients, blending tips, and care advice to ensure your ferns flourish.
Why Good Soil Matters
In nature, ferns thrive in damp, shaded habitats like woodland floors and along stream banks. Replicating these moist, organic-rich environments is key for successfully growing ferns in pots
The soil needs to hold moisture well while still draining properly, It must also contain nutrients to support growth without compacting or becoming waterlogged,
With the right soil mix, ferns will reward you with vibrant, healthy foliage. But use a poorly draining, dense potting soil, and you may battle root rot and other problems.
Providing Moisture Retention
The number one priority in any fern potting mix is moisture retention. Ferns demand consistently damp soil and will quickly decline if they dry out.
To boost moisture retention, incorporate ingredients like:
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Sphagnum peat moss – Absorbs and holds water extremely well. Its spongy texture also improves aeration. Look for quality New Zealand or Chilean sphagnum.
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Coconut coir – Made from coconut husks, coir offers moisture retention similar to peat. It’s a sustainable alternative but may require amendment with perlite or vermiculite to prevent compacting.
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Compost – Introduces organic matter to retain moisture. Opt for high-quality, screened compost.
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Worm castings – The nutrient-rich excrement of worms has excellent water-holding capacity.
Aim for these moisture-retentive amendments to make up at least one third of your total potting mix volume. This ensures the soil will stay evenly moist between waterings.
Improving Drainage
While moisture retention is important, you also need the soil to drain well so roots don’t get waterlogged. Excess moisture can quickly lead to root rot and other fungal diseases.
To improve drainage, incorporate lightweight inorganic ingredients like:
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Perlite – Expanded volcanic glass that creates air pockets for drainage. Mix in at 20-30% of total volume.
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Pumice – Lightweight porous lava rock that loosens up the soil.
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Horticultural sand – Increases drainage without compacting like builders sand.
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Gravel – Small pea gravel or crushed granite helps improve aeration.
Ideally, excess water should flow through the potting mix after watering without leaving the soil soggy or saturated. Test different amendment ratios until you find the perfect moisture/drainage balance.
Adding Nutrients
While ferns thrive in nutrient-poor conditions outdoors, providing some fertility benefits container-grown plants. The enclosed pot has a fixed nutrient supply so amending with organic matter introduces needed nutrition.
Great nutrient sources include:
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Worm castings – Rich in nitrogen, phosphorus, and beneficial microbes.
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Compost – Provides a diverse mix of nutrients.
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Manure – Opt for well-aged manure that won’t burn tender fern roots.
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Organic fertilizer – Mix in mild, balanced organic fertilizer at 1-2 cups per cubic foot of soil.
When preparing your custom soil, thoroughly incorporate nutrient sources like compost or castings with the peat moss, perlite, and other amendments.
Sterilizing Garden Soil
If using any garden soil in your potting mix, it’s wise to sterilize it first. Soil often contains fungal spores that could cause issues like root rot in a container environment.
To sterilize, spread soil on a baking tray and bake at 180°F for 30 minutes. Then let it cool fully before mixing into your potting blend. This kills off any harmful organisms.
Recommended Fern Potting Mix Recipes
Some suitable potting mixes for ferns include:
- 1 part peat or coconut coir + 1 part perlite + 1 part potting soil/compost
- 2 parts peat/coir + 1 part perlite + 1 part worm castings
- 1 part peat/coir + 1 part sand + 1 part compost + 1 part perlite
The ideal blend provides the moisture, aeration, and nutrition ferns require to flourish. Focus on replicating the organic, moist, well-drained conditions they enjoy in nature.
Caring for Ferns in Pots
Beyond a quality potting mix, follow these tips for healthy, thriving ferns:
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Water frequently to maintain moist (but not soaked) soil. Let the top inch dry before watering again.
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Mist leaves often to boost humidity. Use a pebble tray or humidifier.
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Fertilize monthly during spring and summer with diluted liquid fertilizer.
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Keep in bright, indirect light. Rotate pots to prevent one-sided growth.
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Repot when roots fill container, using fresh potting mix.
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Pick an adequate sized pot – shallow pots suit shallow fern roots.
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Avoid overcrowding with other plants that compete for moisture.
With a well-crafted, customized soil and proper care, ferns make outstanding additions to indoor container gardens. Pay attention to their preferences, and your ferns will flourish for years to come.
When to Plant Ferns
When planting evergreen perennial ferns, plant at the same time youd plant any spring blooming perennials (such as creeping phlox or candytuft). Plant other perennial ferns outside in the spring when the fronds are starting to slowly unfurl. Tropical ferns (which tend to be annuals) can be moved outdoors whenever you plant your tomatoes.
How to Feed Ferns
Feed outdoor ferns with Miracle-Gro® Shake n Feed® All Purpose Plant Food in the spring as new leaves are sprouting. Just shake it evenly onto the soil, work it into the top 1 to 3 inches of the soil, then water to start the feeding. The result? Stronger, more vibrant ferns (vs. unfed) that are being thoroughly nourished from roots to tips. Be sure to follow all label directions!
How to Repot a Fern
FAQ
What is the best potting mix for ferns?
A typical mixture contains equal parts of peat moss, sand and garden soil. Add lime (one teaspoon per quart of mixture) for the types of common ferns.
What soil for ferns in pots?
Ferns like soil that is rich in organic matter, such as garden compost or leafmould.
How do you keep ferns alive in pots?
Consistent Moisture — Ferns want their soil to stay evenly moist, not drying out completely between waterings. I keep them in high-traffic areas where I can see them every day. I also use self-watering pots and add a layer of sphagnum moss on top of the soil to help retain moisture.
Is Miracle-Gro potting soil good for ferns?
The best way to prepare the soil for ferns is to add Miracle-Gro® All Purpose Garden Soil to the planting area.