Ferns are fascinating plants to watch, as new leaves unfold from a spiral shape to turn into the magical, arching fronds that adorn the shady corners of our gardens or add interest to the dim corners of our homes.

Understanding that they are forest plants will guide the watering of outdoor ferns. Keep the soil evenly moist but not wet, so give them a little water once a week but more during a particularly hot period in summer, if the soil feels very dry.

Indoor ferns need your careful attention before watering, to check if the soil feels very dry. Sometimes you will need to water them every day but it varies according to their size and whether they are tropical or more temperate ferns.

How much water do ferns need a day?

If your smaller fern is in a sunny room, move it to a place where direct sunlight does not fall directly on it. It will benefit from indirect sunlight. Water at least once a week and if your ambient temperature is cool, that may be enough. Ferns prefer humidity to dryness. In any case, always check if the soil is dry before you water.For larger ferns like a Tree fern, it may need to be checked every day in summer but do take a break from watering in winter, as ferns tend to rest then so they do not need as much. A good tip is to mist it regularly.

Watering tips to keep your ferns looking good

Originally ferns grew in shady forests, so their soil was rich with rotted leaves, which helped to retain moisture. Remember that there are different types of ferns such as tropical ferns, which expect heavy downpours as well as those which are accustomed to colder climates with wet winters.

• Consistent watering, keeping the soil evenly moist but not wet, is the key to keeping your ferns healthy.
• As a general rule, all ferns like damp conditions but not wet roots.
• First of all, make sure that the soil is suitable by adding compost (and leaf mould if available) in spring and autumn.
• After this, water whenever there is a really sunny period or if you notice that the soil around the base of the plant feels dry to the touch.

How often do you water ferns in hanging baskets?

As these are usually outside, they benefit from any rainwater that falls. Test them by touching the soil and if it feels parched, give them water.

As a general rule, outdoor ferns need 1 to 2 inches of water per week but ferns in containers cannot source water from the soil, so they are very susceptible to drying out.

Remember that ferns rest during the winter so you will not need to water outdoor ferns and even indoor ferns will need less water than during the summer, if at all.

How do you tell if a fern is overwatered?

If the leaves turn yellow and even more telling, if there is moss forming in the pot, you are overwatering. Moss loves damp so remove it, and the damaged fronds, and allow the fern to recover.

Epsom salts diluted in water is a gardener’s tip for caring for a neglected fern. Try it and see! Your fern’s leaves should begin to green again quite soon after this.

How often should I water a large fern?

The temperature of the room (or outside) will help you to decide. Ferns prefer a room temperature of 65 to 75 degrees F during the day, but cooler overnight. On really sunny, warm days, water more frequently. The humidity is equally important and when the tips of your ferns have brown tips in winter so try misting the whole plant to increase humidity.

FAQs

Are there different types of ferns?

Yes. There are more than 10,000 species of fern in the world and their fronds were one of the first plants to decorate the Earth. Horticulturalists believe the first ferns grew 400 million years ago.  Think of all the weather zones in the United States and you will understand that ferns have adapted to living in all these areas outdoors.

They range from tropical forest ferns to those that like semi-arid zones to ferns that grow in northern, cooler areas, as well as Mediterranean ferns that grow in Florida. Check what the grower recommends for your indoor fern and do not treat a topical fern in the same way you would care for one from a cooler area.

Do ferns need feeding?

Fertiliser for indoor plants should only be applied sparingly. If you use the same feed as you do for tomatoes, you will damage the roots of your fern. So if you notice yellowing leaves, you can remove them then feed the fern. I recommend 2 tablespoons of Epsom Salts dissolved in a gallon of water, which will ensure your ferns keep their verdant green colour throughout the summer.

Can you split ferns to make new plants?

Ferns can be divided when you re-pot to make two plants, by carefully cutting the fleshy roots and gently pulling to make two or sometimes three new plants. They live long lives if you care for them properly so you can give these extra ferns to friends or charity sales if your growing space is limited.

How can you add colour to complement outdoor ferns?

Although ferns are shade lovers, you can find plenty of companion plants to add some colour to your fern corner. Caladiums can be planted as bulbs in spring when you add your first layer of compost to the ferns. Their colourful foliage will add a dash of pink to your shady green fern corner. Bluebells love shade too and you will often find ferns and bluebells in the wild, but keep an eye on them as these can spread widely.

What can go wrong with outdoor ferns?

1. If the soil is not rich enough or you don’t water consistently, ferns will react by wilting. However, if the air temperature is below 60 degrees F, then only add water only when the soil is dry to the touch.
2. Some of the more tropical ferns may grow poorly in low temperatures, preferring to be warm. Try to plant them in sheltered spots and ensure the soil is kept moist.

What can go wrong with indoor ferns?

1. If your fern is in direct sunlight, it may suffer leaf burn. Remember how it grows in the wild? Shade is better for your fern or indirect sunlight, so move it.
2. If your fern looks unhealthy, first remove any yellow leaves then try feeding it using 2 tablespoons of Epsom Salts in a gallon of water. Many gardeners say their ferns improve after a monthly feed, but speak kindly to them too!
3. Humidity is necessary for healthy ferns and some gardeners use humidifiers to keep it consistent.

Should I cut off old brown leaves on my fern?

Yes, they will not grow back. Cut as close as you can to the base of the plant.

Keep your ferns looking good by:

1. Re-potting ferns every 2-3 years. When you do this in spring, cut off any brown leaves, add compost and give your fern a larger pot.
2. Making your own leaf mould to nourish the soil around ferns so that it resembles the forests from where they originated. Just rake autumn leaves and store them in a plastic bag. Make some holes to allow ventilation and just leave it all winter in a corner of your garden or a shed. It will be ready for the first spring composting for your garden. Indoor ferns like a little crumbled into their soil too. Bring the outdoors inside!
3. Consistent watering. You can also mist your ferns indoors with warm water to increase humidity or sit your fern on a plate or tray with damp stones, not actually immersed in it.