Frosty Fern (Selaginella kraussiana), also known as Krauss' spikemoss, is a charming, low-growing, fern-like plant that is loved for its delicate, bright green foliage with a frosty, silvery appearance. It's not technically a true fern but a type of spikemoss, which belongs to the Selaginellaceae family. Frosty ferns are commonly used as decorative plants in homes and offices due to their lush, unique appearance.

Here’s how to care for your Frosty Fern indoors:

Light Requirements

• Bright, Indirect Light: Frosty Ferns thrive in bright, indirect light. They will do well near a window with filtered sunlight, but avoid placing them in direct sunlight, which can scorch their delicate leaves.
• Low Light Tolerance: While Frosty Ferns can tolerate lower light conditions, they will not grow as vigorously and may become leggy. If possible, provide as much light as you can without direct sun exposure.
• Artificial Light: If natural light is limited, a grow light can be used to supplement the light needs of the plant.

Temperature

• Warm Temperatures: Frosty Ferns prefer temperatures between 60-75°F (15-24°C). They do best in a warm environment but are sensitive to extreme cold.
• Avoid Cold Drafts: Keep your plant away from drafts, air conditioners, or heating vents, as these can cause temperature fluctuations that stress the plant.

Watering

• Consistent Moisture: Frosty Ferns love moisture and prefer their soil to be kept consistently damp, but not waterlogged. They don’t like to dry out completely between waterings, so keep the soil evenly moist.
• Watering Frequency: Water your plant when the top of the soil feels slightly dry to the touch, but be careful not to let it dry out too much.
• Avoid Overwatering: Ensure that the pot has good drainage to avoid the plant sitting in stagnant water, which can lead to root rot. Always empty any excess water from the saucer.
• Use Room Temperature Water: Use room temperature water when watering, as cold water can shock the plant.

 Humidity

• High Humidity: Frosty Ferns thrive in high humidity. Aim for humidity levels around 50-70%, though they will tolerate slightly lower humidity.
• Increase Humidity: In dry indoor environments, especially during winter, you may need to increase the humidity around your plant. You can do this by:
• Placing the plant on a humidity tray filled with pebbles and water (making sure the pot doesn't sit directly in the water).
• Using a humidifier in the room.
• Mist the plant occasionally with water, especially if the air is very dry.
• Avoid Dry Heat: Keep the plant away from direct heat sources like radiators, space heaters, or vents that can dry out the air.

Soil

• Well-Draining, Moist Soil: Frosty Ferns prefer a rich, moist, and well-draining potting mix. A standard houseplant potting mix should work well, but you can mix in some peat moss, perlite, or sand to improve drainage and aeration.
• Acidic Soil: These plants prefer slightly acidic soil (pH 5.0 to 6.0), so make sure the potting mix is on the acidic side.

Fertilizing

• Light Feeding: Frosty Ferns do not need heavy feeding. You can fertilize your plant once a month during the growing season (spring and summer) with a diluted, balanced liquid fertilizer. Use half-strength fertilizer to avoid overfeeding.
• No Fertilizing in Winter: During the fall and winter months, when the plant is not actively growing, reduce or stop fertilizing altogether.
• Organic Options: A light application of organic fertilizer or compost can also be beneficial, but avoid heavy or high-nitrogen fertilizers that can encourage leggy growth.

Pruning

• Minimal Pruning: Frosty Ferns generally do not require much pruning. You can remove any brown or yellowed leaves to keep the plant looking tidy and encourage new growth.
• Cut Back Leggy Growth: If your plant becomes too leggy, you can trim it back to encourage fuller growth. Trim the stems gently with clean scissors or pruning shears.

Pests

• Watch for Common Pests: Frosty Ferns are relatively pest-resistant, but they can occasionally attract pests like mealybugs, aphids, and spider mites.
• Treatment: If you notice pests, treat the plant with insecticidal soap or a diluted neem oil solution. You can also wipe the plant’s leaves with a damp cloth to remove pests manually.
• Mold or Mildew: Since this plant thrives in humid environments, ensure that the humidity is not excessively high, as this could encourage mold or mildew. Keep the foliage dry, especially around the base, to avoid these problems.

Repotting

• Repot Every 1-2 Years: Frosty Ferns grow slowly, so they do not need frequent repotting. Repot your plant every 1-2 years or when it outgrows its pot.
• Choose a Slightly Larger Pot: When repotting, choose a pot that is only slightly larger than the current one to prevent excess moisture retention, which could lead to root rot.
• Fresh Soil: Use fresh, well-draining potting mix when repotting to give the plant the nutrients it needs.

 Common Problems

• Yellow or Brown Leaves: If the leaves turn yellow or brown, it may be due to inconsistent watering (either too much or too little), low humidity, or temperature stress. Ensure consistent watering, good humidity, and avoid extreme temperature fluctuations.
• Leggy Growth: If your Frosty Fern becomes leggy (long, spaced-out stems), it may not be getting enough light or might be suffering from under-watering. Try moving it to a brighter location and ensure regular watering.
• Leaf Drop: Leaf drop can occur if the plant is placed in a location with insufficient light, humidity, or temperature instability. Make sure the environment is stable and suitable for the plant's needs.

Indoor Placement

• Good for Terrariums: Frosty Ferns are perfect for terrariums or glass containers because they enjoy high humidity and can thrive in these enclosed spaces. Just make sure there's enough air circulation to prevent mold or mildew growth.
• Avoid Crowding: Make sure your plant has some space to breathe, as overly crowded environments can lead to poor growth and pest issues.

Winter Care 

• Cooler Winter Temperature: In winter, you can slightly reduce watering, but be sure not to let the plant dry out completely. Frosty Ferns may also slow down in winter, so don’t worry if they look a little less vibrant.
• Humidity Management: Winter air tends to be drier, so ensure your plant has enough moisture around it. You might need to increase misting or use a humidifier to maintain a healthy environment for your plant.

The Frosty Fern is a charming, low-maintenance plant that can thrive in a humid, well-lit, and consistently moist environment. By providing bright, indirect light, maintaining high humidity, and watering properly, your Frosty Fern will remain a beautiful and unique addition to your indoor garden or terrarium. It's a forgiving plant, but consistency is key—especially when it comes to humidity and moisture. With a little attention, you'll enjoy its lovely, frosty foliage for years to come!