How to Water Boston Ferns: My Easy Step-by-Step Guide

For a Boston fern (Nephrolepis exaltata) to thrive indoors, it needs specific considerations when it comes to watering. In this guide, I’ll take you through the basics of when and how to water Boston Ferns at home and the go-to strategy I use for keeping my plant in optimal health throughout the year.

When Should I Water a Boston Fern? Key Takeaways

Boston ferns are native to the humid jungles of tropical Africa and South America. Their soil must be kept consistently damp for optimal plant health. During the growing season, water every 2 to 3 days with distilled, filtered, or rainwater when the top inch of soil feels dry to the touch. Humidity can also be maintained through misting or using a pebble tray.

What are the Typical Water Needs of a Boston Fern?

Boston ferns always need slightly moist soil to keep them from drying out. Water Boston ferns more regularly in the spring and summer and less frequently in the autumn and winter. The trick is to avoid stagnant water in the potting vessel to ensure suitable drainage. 

To prevent contamination from chemicals, use distilled, filtered, or rainwater. Boston ferns also need high humidity, which can be achieved through misting or using humidifiers and pebble trays. 

When Do I Know When a Boston Fern Needs Watering?

The easiest way to check if your Boston fern needs a drink is to test how dry the soil feels. I like to check this daily using my fingertips. If the soil feels a little bit dry, the fern needs water. 

Moisture probes can also be effective if you’d rather keep your nails clean and provide a better indicator of moisture content deeper in the soil base. 

The foliage can be a more drastic indicator. If the fronds are starting to yellow, the plant is parched and needs a drink.

How Often Should I Water a Boston Fern?

Boston ferns should be watered as often as necessary to keep the growing medium slightly damp. Depending on your climate, this may involve watering anywhere from every 2 to 3 days or once a week. 

During the growing season, water at this frequency. In the winter, I cut back the frequency, and only water the fern every couple of weeks as growth will naturally slow during this period of dormancy.

What Type of Water is Best for Boston Ferns?

Like most types of ferns, Boston ferns can be vulnerable to chemicals and salts in tap water. To avoid a sickly-looking plant, use rainwater if possible. If that’s not practical, then use distilled or filtered water (this is what I do). The latter is probably the most practical option for most Boston fern owners.

Ensure that any water you use is at room temperature because Boston ferns don’t like temperature extremes.

How to Water Boston Ferns

If your Boston fern needs watering, follow a few simple steps to avoid over or underwatering the plant.

1. Always use a pot that has drainage holes. Water the fern thoroughly until water begins to drip out. Try not to get any water on the fronds themselves. Instead, aim for the soil around the base of the plant.

2. To keep humidity high, it’s worth misting the fern every few days. Don’t get too liberal with the spray, though, as you want to avoid completely saturating the foliage. You can also place the fern’s nursery pot on top of a pebble tray with some water in it. The water will evaporate and raise the humidity.

What to Do In Between Watering Cycles?

Regularly check your soil between waterings, especially in the spring and summer. Use your fingertip or a moisture meter to check if the top of the growing medium is beginning to feel dry. This tells you if the fern is ready for another watering cycle.

Never allow a Boston fern to totally dry out. This is a killer for the plant.

For more, see our in-depth guide on where to position Boston ferns in the home for optimal care and Feng Shui benefits.

Overwatering and Underwatering Boston Ferns

Boston ferns are incredibly vulnerable to both overwatering and underwatering. Too little water will cause the fern to dry out and die. Too much water will initiate root rot. Keep an eye out for:

Root rot

If a bad smell starts to come from your Boston fern, check the roots. The roots are rotting if they appear brown, mushy, and smelly. Cut off affected roots and let the soil dry out a bit before you resume watering.

Wilting fronds

This is usually a symptom of overwatering. If the fern’s foliage is drooping, but the soil is still wet, there’s too much water in the soil. Let the soil dry out a bit, and adjust your watering schedule.

Yellowing foliage

This could indicate underwatering or overwatering. If you see the leaves turning yellow or display brown tips on the fronds, check the soil with your finger. If it’s soaking wet, avoid watering until the soil dries out a bit. If the soil is dry, water the plant thoroughly.

How to Water Propagated Boston Ferns

Boston ferns can be propagated by division or using the running shoots that develop. Whichever method you propagate, keep the new plant’s soil moist but not waterlogged – just as you would for a mature plant.

Watering Boston Ferns After Repotting

Boston ferns typically need repotting every couple of years as the plant spreads. Giving the plant a quick water a couple of days before repotting is a good idea. This makes transferring some of the old soil to the new pot easier. Once it’s been repotted, give the fern a thorough drink.

Watering Boston Ferns FAQs:

Wrap Up

Boston ferns may seem fussy when it comes to water. But by following a simple routine, you can ensure that your fabulous fern gets the right amount of water to truly thrive.

Only water when the soil feels slightly dry, especially in the spring and summer. Reduce watering frequency in the winter. Always use room-temperature distilled or filtered water.

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