How Often Should You Water Ferns Outside?

How Often Should You Water Ferns Outside

Ferns are lush, non-flowering plants that can bring a lovely, tropical vibe to your porch, terrace or outdoor garden, whether planted in pots, hanging baskets, or in the ground. Surprisingly, these plants are also super hardy and can thrive outside without too much of a problem.

But – how often should you water your ferns if they are outside? If you are planning to grow your ferns outdoors and are clueless about their watering needs, then read on!

Do ferns grow well outside?

Although ferns are well known as indoor houseplants, most varieties can also flourish outdoors. These hardy plants can survive the harsh outdoor temperatures, whether it is the scorching heat of summer or the freezing temperatures over winter.

Hence, it is perfectly fine to grow your ferns outdoors, as long as you are growing a hardy variety like the Boston fern, and as long as you provide them with the right growing conditions. Ferns, in general, do best in moist and shady areas. For faster, healthier growth, make sure to place your plants in a spot where the temperature is between 60 and 70 degrees Fahrenheit. 

How often should you water ferns outside?

When it comes to watering, outdoor-grown ferns are generally less demanding than their indoor counterparts. However, they are used to growing in areas with lots of humidity and rainfall, so you will need to ensure that they receive adequate water to thrive and remain verdant.

In general, ferns need about one to two gallons of water per week, which is approximately equivalent to a once-weekly watering. Keep in mind, though, that your watering routine should be adjusted according to your local climate. For example, you might need to water your plants every two to three days during the hot summer season. 

The type of fern you are growing will also dictate how much water it needs. Some fern varieties, like the Boston and staghorn ferns, need regular moisture, while those like the asparagus fern and the western sword fern do not transpire as much water due to their very thin leaves. Thus, they do not need watering as frequently as the other fern varieties. 

Finally, the type of growing medium can also influence how often you need to water your ferns. Some people grow ferns as part of a garden landscape, while the others plant them in smaller containers or pots. We have explained below how each of these growing environments affects your watering routine:

1. Fern planted in garden soil

Establishing the correct watering routines for your ferns is essential for healthy roots and foliage. However, the frequency of watering will be greatly affected by the type of soil in which the plants are grown. In the case of ferns planted in regular garden soil, they might not need as much watering as those grown in containers. That is because these plants can establish a more extensive root system that grows deep into the ground, so they can find moisture at a deeper level than a container-grown plant.

2. Fern planted in a pot

Ferns planted in pots might need more watering as the soil in a pot tends to dry faster than that in a garden bed. As a general rule, potted ferns should be watered at least once a week; however, this might also depend on the type of pot you have used. 

For example, if you are using terracotta pots, the soil will probably dry out faster as terracotta is a porous material. That means you will need to increase the watering frequency to keep your plants hydrated.

On the other hand, using plastic pots can have the opposite effect. Plastic pots tend to retain more moisture, making them an ideal choice if you live in a dry region. This way, you will not need to give your ferns as much water as those in terracotta pots, as the soil will stay moist for longer.

Other factors, such as the size of the pot, outside temperature, season, and type of soil might also affect the watering needs of your ferns. The only sure-fire way to know for sure when they need watering is to check the soil from time to time. The top layer of soil should be dry to the touch before you water your plants again.

3. Fern planted in a hanging basket

Similar to pots, the soil in hanging baskets also tends to dry out quite quickly. The roots of your ferns are exposed to the air all day, increasing the moisture evaporation rate, especially on hot, sunny days. 

To keep a fern well-hydrated in a hanging basket, it is recommended to water it every two to three days. Once again, make sure that the top layer of soil is dry before watering. You can insert your finger into the topsoil to know whether your plant needs a drink or not.

Other factors to consider

Aside from the specific fern variety and the growing medium, several external factors need to be considered when watering your outdoor ferns. These factors affect how much water your fern will need at a certain time or in a certain location. As these factors can change, there might be times when you need to adjust your watering schedule instead of blindly adhering to the same routine.

These are the main things you need to consider when watering your outdoor ferns:

1. Weather

Changes in the weather can affect the water requirements of your ferns, so be mindful of the current conditions and adjust your routine accordingly. On rainy days, you do not need to water your ferns so much. On the other hand, make sure to keep them well hydrated if there is no rain for several days or weeks.

2. Sunlight exposure

While most fern varieties enjoy a bit of full sunlight, the scorching heat of the sun can also dry out the soil pretty fast! That means your sun-exposed ferns will need more water to maintain healthy roots and leaves.

3. Season

Ferns are generally hardy perennials that can survive the harsh outdoor conditions, including the winter weather. Some varieties also go dormant for a period when the cooler months arrive, which means you will need to reduce the frequency of your watering when the freezing temperatures set in.

4. Spacing

Just like most plants, ferns that are planted close to one another in the same soil will have to compete for the available water resources. This would mean watering your plants more frequently to keep them all hydrated.

5. Container size and drainage holes

If you are growing your ferns in containers, keep in mind that the size and drainage holes of your containers can affect their water-holding capacity. The larger the container, the more soil it holds, and hence the more water it will hold, too. In this case, you should avoid watering your ferns too frequently. A small container, on the other hand, will dry out faster and need watering more often.

The drainage holes also matter when choosing a container – they are a non-negotiable criterion! These holes help the excess water escape from the soil and thus prevent root rot. 

6. Temperature and humidity

Temperature and humidity both play a role when it comes to your plants’ water requirements. Higher temperatures can put your ferns under heat stress, while an excessively humid environment can promote the growth of bacteria and mold. Hence, you should adjust your watering depending on both temperature and humidity to avoid any issues.

Signs of watering problems in ferns

Most fern varieties love moisture. Nevertheless, too much water can have dangerous consequences for your plants. Conversely, if you are a busy plant parent and often forget to water your ferns, this can have detrimental effects, too!

Both overwatering and underwatering are common mistakes among novice gardeners, and striking the right balance might seem overwhelming at first. But do not worry – there are some early tell-tale signs that will alert you when you need to adjust your watering habits. Check out these symptoms so that you can save your ferns from incorrect watering before it is too late. 

1. Underwatering problems in ferns

We are all guilty of underwatering our plants from time to time. Underwatering can be caused by complete neglect, not giving the plant enough water when you do water it, or incorrect watering in relation to the season. 

Fortunately, it is easier to save an underwatered fern than an overwatered one, provided you catch the problem in time. So, how do you know when your fern needs water? These are the common signs:

  • The soil around the fern feels bone dry to the touch.
  • The leaves appear droopy.
  • The leaves are wilting, curling, and turning brown.
  • The leaf edges are becoming dry and crispy.

2. Overwatering problems in ferns

Overwatering is the leading cause of root damage in plants, including ferns. That is because, in simple terms, too much water can drown a plant. When the soil is waterlogged over an extended period, it deprives the roots of oxygen which will eventually kill the entire plant. 

Overwatering can come about due to insufficient drainage, watering too frequently without considering the plant size and season, or overestimating the watering needs of the plant.

Some of the key signs that your ferns are overwatered are as follows:

  • Your ferns’ leaves are turning yellow.
  • The leaves are wilting – a symptom shared with underwatering.
  • The soil appears wet and saturated.
  • The leaves and stems look soft or squishy.
  • After some time, your plants might start to show signs of fungal infection.

How long can ferns go without water?

As mentioned, ferns are hardy plants that can survive outdoor conditions – and even drought conditions, up to a point.

Depending on the variety, ferns can generally survive about two to three weeks without water. However, some ferns that are drought-sensitive might only make it for a few days.

Thus, it is best to be on the safe side and water your ferns regularly to avoid any drought-related stress.

How do you take care of an outdoor fern?

Although caring for your outdoor ferns requires fairly minimal effort, you do still need to keep an eye on your tropical greens to ensure that they are growing happily. These tips should help you care for your ferns outside:

  • Water your ferns correctly. Make sure that the soil is neither waterlogged nor bone dry, as both of these conditions can be detrimental to the health of your plants!
  • Trim any damaged stems or fronds regularly to keep your ferns in top shape. Regular pruning will also prevent the spread of any potential plant diseases and promote bushier growth of the leaves.
  • Keep your fertilizer application in check. Sometimes, too much fertilizer can affect the water uptake of your ferns.
  • Use a well-draining pot and soil. Like most plants, ferns can fall victim to root rot if you leave them in waterlogged soil for too long.
  • Consider repotting your plant if it seems to have outgrown its container. This will allow more space for its roots to spread.


One of the keys to successfully growing your ferns outside is proper watering – and a rigid watering schedule might not always do the trick! Several environmental factors can affect the moisture needs of your plants, including the fern variety, local weather, soil type, and many others. So, make sure to adjust your watering routine in line with these factors, and with the right care you can enjoy your outdoor ferns for years to come!

Image: / Adrian Teoh