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How Often To Water Ferns? (Calculator)

Ferns are a large group of beautiful and unique plants that differ in cultivation methods and have different water needs. To avoid side effects, you need to know about watering frequency and the amount of water.

Ferns need to be watered once a week. The amount of water can be from 1-2 gallons (for ferns grown outdoors) to 0.5 gallons. or less for ferns grown indoors in pots. Water a fern that grows indoors once every 10 days, up to 1 gallon of water.

In clay soil, fern needs watering no more often than once every 10-14 days. To determine if a fern needs watering, you need to check the soil moisture, and if the top layer has started to dry out (0.5 inches), you need to water the plant.

In fact, the frequency of watering depends on many factors, and this is what will be described in this article.

Fern Watering Calculator

outdoors indoors
Number of waterings in a drought:
Amount of water:

Conditions Frequency and Quantity
In garden soil (outdoors) Water once per week in the absence of rain. The amount of water is 1-2 gallons depending on the size of the plant.
In pots (indoors) Water once every 5-10 days. If the air is too dry, more frequent watering is possible. The amount of water should be sufficient to humid the soil in the container.
Clay Soils In clay soil, you need to create drainage under the fern and water no more than once every 14 days (if no rain).
Fast Draining Soils Sandy quickly drained soils are not the best for growing fern. Water once every 7-10 days or more if needed.

Watering indoors

Growing ferns indoors is a prevalent practice. Here watering is different because the humidity in the room is usually lower, and the fern is known to love humidity.

At temperatures above 75 degrees F (23 ° C), the fern needs more frequent watering, especially if it is planted in small containers. Some species of ferns in these conditions require daily watering.

Frequent watering is needed because, in dry conditions, the plant evaporates too much moisture. In this case, it makes sense to make the air wetter.

You can install a humidifier to humidify the air around the fern. Also, the right solution would be to spray the leaves with water at least once a day. Some people place a fern in the bathroom to achieve the same goal.

If the humidity reaches 60%, you can reduce watering. For some species, if they grow in large pots, watering will be required every ten days.

The amount of water will be different. For smaller pots will be enough 0.25 gallons (0.75 liters) or even less. For large plants, the amount of water can increase to a half-gallon or more.

It would be best to moisten all the pot’s roots well, but the soil should not be soggy but only moist.

To find out for sure if your fern needs watering, stick your finger in the soil, and if it is more than half an inch dry, you should give water to the plant.

You can also check the weight of the pot and the color of the soil. A container with dry soil is lighter than wet. Also, dry soil has a lighter color; moist soil is darker.

Some fern species can withstand a short drought (no more than a few days) and usually require less watering.

Next, we will consider all the main varieties of ferns, and I will briefly tell you what water requirements they have.

Boston fern

This type of fern is quite hardy and can tolerate fairly bright lighting. But in such conditions, it will need more moisture.

If you plant it in indirect sunlight indoors (at some distance from the window), then the plant will evaporate less moisture, and watering will be required every 7-10 days, depending on the pot’s size.

Although the plant can tolerate not too high humidity, the soil around it should always remain slightly moist.

Asparagus (foxtail) fern

This type of fern has thin leaves and therefore evaporates less water. This means that it needs to be watered less than other ferns.

However, if the air is dry, then this species will need a little more watering.

Staghorn fern

Staghorn fern is a unique type of fern, and it has broad leaves and a compact root system. A trendy way to grow is on a board hanging on the wall. Moss is used as a substrate.

In dry air in the room, the moss dries very quickly and needs to be moisturized daily. Moss should always remain moist.

If the temperature is not hot and the humidity is high enough, then the substrate will not dry out quickly, and you will need to water once a week.

Regular spraying of ferns with water will also be a great solution.

Maidenhair fern

Maidenhair fern has small leaves, but their number is quite large. Watering this fern is about the same as in most others.

On average, watering should be once every 7-10 days, but if the plants grow in small pots and a dry environment, the frequency of watering can increase up to once every 3-5 days.

Birds nest fern

Bird’s nest fern loves high humidity, so you should place a humidifier near the plant.

In a humid environment, the plant can remain for up to one week without water. It can also tolerate short droughts but does not let the soil dry out more than an inch.

Lemon button fern

Lemon button fern likes frequent generous watering. This is especially true if it grows in small pots.

Kimberly queen fern

Kimberly queen fern requires a standard watering regimen (once a week), but you should keep the soil in the pot constantly moist.

Outside watering

Watering ferns from the outside are very different from watering indoors.

First of all, these plants need watering in the absence of rain for an average of 5-7 days. The amount of water will be 1-2 gallons (3-7 liters), depending on the plant’s size and soil type.

Next, we will consider in more detail the need for watering, depending on different growing conditions.


Ferns need water the most in dry and hot weather. If it hasn’t rained in seven days, it’s time to water the plants.

As I wrote above, the amount of water for each plant will be different. One or two gallons is usually enough, but you can give a little more water if the bush is huge.

You need to moisten the soil well, but you don’t want to make a swamp. How to water correctly, we will talk below.

At temperatures below 60 ° F (15 ° C), water the fern less often because the plant does not evaporate too much moisture. Give water only when the topsoil is dry (1 inch).

In cloudy weather with little rainfall, watering is usually not necessary. However, you should still check the soil moisture. If the rain has not soaked the ground to its full depth, then you can slightly moisten it (not more than half a gallon of water for each plant).

Soil type

There are different types of soils in other parts of the world, and plants have adapted to them differently. However, all these soils can be divided into two types: fast-drained and slow-drained soils.

Quickly drained soils mainly consist of sand or small stones. In such a land, water is retained very poorly, and it dries quickly in drought.

For some plants, this is good, but not for ferns. Therefore, if you have similar soil in the garden, you need to water them much more often. In dry weather, you may have to water every two days. The amount of water can reach three gallons.

To determine more precisely whether the fern needs watering, check that the soil is not dry if dry, then give the plant water.

To avoid frequent watering, you can make your soil more moisture-retaining. This can be achieved by adding compost to sandy soil.

Slowly drained soils generally contain a lot of clay, i.e., a material that has a high water holding capacity.

In such soil, the fern should be watered not too often. In drought, it can be once every 7-10 days. In cloudy weather but without rain, watering will be required once every two weeks.

Soils that retain a lot of moisture are not the best substrate for growing ferns. To improve it, you need to add compost or other organic matter. These components will make the clay soil loose and permeable.

How to water

Now I will tell you how to water it properly and when it is better to do it.

Best time

As with most plants, the best time to water a fern is in the morning, before the sun begins to shine brightly enough.

The beginning of the day is better suited for watering because the water will have time to wet the soil before the midday heat.

The second advantage is that the water will evaporate during the day, and for ferns, it is perfect because these plants love high humidity.

Watering in the evening is not the best practice because, at night, the plants do not lose moisture, so they do not need much water. However, fungi and bacteria can grow well at this time.

Amount of water

The amount of water for a fern growing outside can vary from 0.5 to 3 gallons (1.8-10 liters) of water per watering.

If the yard has sandy soil and the fern bush is huge, the plant should be saturated with moisture (at least 2 gallons of water). If the heat is too intense, the amount of water can go up to 3 gallons.

For compact ferns growing in clay soil, half a gallon of water is usually enough.


For watering, it is best to use a hose with a sprayer. Water the fern on top to moisten the leaves.

If the water spills around, it’s okay. In this case, there will be more humid air around the plant.

I recommend watering in two stages (of course, if you have time for this). The first stage is pouring a third of the amount of water and soaking the top layer of soil.

After a while, pour the rest of the water. In this case, more water will penetrate the soil. This is especially true in the summer heat when the surface dries quickly and turns into a hard crust.

If possible, install drip irrigation. In this case, the water will continuously moisturize the plant, and you do not have to waste time and be afraid that the plant will dry out.

The main thing is to properly adjust the watering not to give the plant too much moisture.

Watering newly planted ferns

After planting the ferns, watering will be different from the usual schedule.

No matter what kind of fern is planted, you should always keep the soil around the plant moist. Even if this fern can tolerate a slight drought, it should have enough moisture in the beginning.

Water as often as needed to keep the soil slightly moist. In drought, it can even be twice a day. Just check the soil moisture and water if it is dry.

This watering schedule you should follow the first 4-6 weeks after planting. When the fern takes root, you can switch to the regular frequency of watering.

Additionally, I recommend shading the fern with a net or something similar (umbrella) for a few weeks to reduce the sun’s effect on the plant.

You can also soften the rooting conditions to spray the fern with water at least once a day.

Overwatered Fern

Even though the fern loves moisture, too much water can damage the plant.

With excess moisture, the plant’s roots and crown may begin to rot, and as a result, the leaves will start to turn yellow. If you do not solve the problem in time, you can lose the plant.

It is not easy to pour the fern by hand; for this, you need to water often and with plenty of water. However, I do not recommend exceeding the watering limits given in this article.

A slight excess is not critical, but try to follow the recommendations. Also, do not water the fern during the rains.

In winter, ferns also do not need watering. An exception may be an area where there is a drought in winter. In this case, from time to time, slightly moisten the soil around the plant.

Overwatering most often occurs during prolonged rains. If it rains a lot in your area, try to divert water away from where the fern grows by digging a drainage ditch.

If the soil in your area is high in clay, arrange for drainage under the plant. To do this, before planting, pour stones or expanded clay on the bottom of the planting hole. In this case, the water will drain below the root level.

Another common cause of overwatering is improperly configured automatic watering. In this case, watering may be turned on too often, there may be too much water, or watering may be turned on the day after the rain.

To solve the problem, set up the automatic watering controller correctly.

If the fern has suffered from overwatering, dig it up and clean it out of the soil. Remove rotten tissue and wash the wound with a fungicide solution.

Put the fern in a container with sterile soil and place it undercover. Water it very sparingly. The recovery process can take a whole year.

Lack of water

Underwatering is another problem that can occur when you are growing ferns. The leaves of the plants will begin to wither and lose their bright green color.

If you notice similar symptoms, you need to check the soil moisture and water the plant if necessary.

Underwatering often occurs during periods of drought. You may not water in time, or the most common case is when you watered, but the soil is not wet completely.

You always need to check the soil moisture before and after watering to determine exactly how much water the plant needs. Try not to let the ground dry out for more than half an inch.

If you still did not give the fern enough water but noticed you mist in time, the plant can be saved. Just water it several times a day to saturate the soil with moisture. At the same time, use a small amount of water to prevent the formation of a swamp.

One or two days of such watering, and the plant will come to life. Cut dry leaves and shoots. In a few months, the plant will recover.

Also, that to avoid underwatering, I recommend mulching the fern with quality materials. Chopped pine bark or compost is best for this. Buy mulch only from reliable manufacturers.