Ferns are becoming quite popular houseplants, mostly because of their stunning leaves which are also called fronds.
Outdoor ferns require a bit of different care compared to indoor ferns, yet both types are quite easy to grow and undemanding when it comes to feeding.
However, improper choice of fertilizer can significantly damage this plant, especially Boston fern that is more sensitive to plant food.
So I have done the research and have created a list of the most suitable fertilizers for ferns.
Fertilizer for ferns
Fertilizing indoor ferns – which plant food to use
As already mentioned, fern plants are quite low maintenance.
Outdoor ferns are even easier to take off compared to indoor ferns – both types require a lot of high soil moisture, as well as frequent watering, and indirect light. If you cannot enable indirect sunlight in indoor conditions, I would then suggest using curtains to get filtered light.
Now, let’s get back to proper fertilization.
Fern plants generally do not require a lot of plant food – typically in the growing season, the plant will need monthly feeding.
This depends also on the growing conditions.
Your outdoor ferns will prefer slow-release fertilizer. These plants mostly use nutrients from the soil, thus adding extra nutrients through compost is not necessary. After planting, add the compost once at the beginning of the spring.
Indoor plants have a slightly higher demand for minerals. Because mimicking the natural environment of ferns is a bit tricky, most ferns grown indoors require that extra boost to grow.
It is recommended to use a well-balanced fertilizer, with the same percentage of three main nutrients: nitrogen, potassium, and phosphorus. Besides these, your fern plant won’t require any.
One thing you should keep in mind is that some types of ferns, such as Boston ferns, are more sensitive to the presence of residues in the soil.
Now, let’s check out the products!
QUICK OVERVIEW: Best Fertilizer for Ferns
Watering Can Singles
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Miracle-Gro Indoor Fertilizer
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1. Miracle-Gro Indoor Fertilizer
If you have been following this blog for some time now, then you have probably heard of Miracle-Gro Indoor Plant Food, 8-Ounce (Plant Fertilizer) (2 Pack).
This is my go-to compost for indoor gardeners and it works for ferns as well.
If you own a bigger indoor garden, you can use this food for other plants too, since it was designed to match all indoor plants.
Also, Miracle-Gro is one of the most popular companies for different gardening products – you will notice that their products are one of the highest-rated ones, so your fern will be thankful for the nutrients it gets from their compost.
- Manufacturer: Miracle-Gro
- Item weight: 10.6 ounces
- Package dimensions: 7.68 x 5.75 x 1.85 inches
Picking a proper fertilizer for ferns is sometimes difficult as certain species are more sensitive to not only certain elements but residue in the soil as well.
One of those types is Boston ferns, the most common type of ferns for indoor gardens.
However, with careful choice of food and proper application, it will thrive!
The NPK is 1-1-1, making it suitable even for the most sensitive indoor ferns.
You won’t have to worry about plants getting dry or burnt leaves, as the level of nitrogen is lower compared to other options on the market.
When it comes to application, I have some advice.
On the bottle, you will notice that weekly fertilization is recommended. However, I wouldn’t follow this suggestion blindly.
Even though the formulation is suitable for indoor plants, not all of them have the same demand for nitrogen, potassium, and phosphorus.
As stated, ferns do not need a lot of these minerals, so weekly feeding is not necessary.
Instead, use it once a month through spring and summer. Once fall and winter arrive and the development of the plant slows down, you can even cut back to feeding every two months.
Another thing I would suggest is to never add it directly into the soil, even though the instructions say to do just that.
That direct application could suit other plants, but it could be quite damaging for ferns, especially the Boston fern.
I always dilute it in water – one squirt is enough for a dixie cup. During application, I would make sure to get the soil evenly moist and water it generously afterward.
Until the next feeding, water frequently and check the foliage – if you notice any burns, it could be that the fern is overfertilized.
- Easy to use
- Promotes the growth
- Suitable for Boston ferns
- Easy to use and long-lasting
2. Shake ‘N Feed Continuous Release
The one thing gardeners have the most trouble with is maintaining the leaves of ferns.
Fronds turn yellowish easily when there are not enough minerals in the growing mix.
Further recovery of the garden is tricky since ferns are sensitive to some elements.
Miracle-Gro 3002910 Shake ‘N Feed Continuous Release Palm Plant Food, 4.5 lb, Brown/A can help you with gardening and managing those garden beds of Boston ferns and hardy ferns.
The benefits of continuous release food are numerous.
Firstly, you won’t have to worry about burns possibly caused by one of the minerals, as the elements are slowly delivered to the roots.
Also, gardening with this type of food is easier. There is no need to fertilize the plants as much, since they are still getting the nutrients, just over the extended period due to gradual release.
This type of continuous delivery suits the ferns a lot, and other species in your garden could benefit from the use of such food as well.
- Manufacturer: Miracle-Gro
- Item weight: 5.12 pounds
- Package dimensions: 4.13 x 9.8 x 7.5 inches
Let’s start with the nutrients this food contains.
The NPK is 12-4-8, so as you can see it is not a well-balanced food – the one that ferns typically prefer.
However, if you choose the right potting mix, this NPK won’t damage the plant.
I would like to share a few tips because of the higher level of one nutrient – N.
12% of N is not a lot, but considering that the percentage of the other two elements is below 10%, you should be careful when applying the food.
Frequent watering is necessary, as slow-release food works better when the soil is evenly moist. I wouldn’t recommend using this food for a Boston fern, but for other types, it should work more than okay!
Once you feed the plant, you won’t have to reapply the food for another three months.
During that three-month break frequently check the plant – if other growing conditions are satisfied (the plant is away from direct sunlight, watered regularly) and you can see that the plant is struggling, that means that you should repeat the feeding.
This time, it is not necessary to use the same amount of food, a bit less is more recommended since it is an extra feeding.
If the foliage is still vividly green, then there are enough minerals in the soil.
This food should never be used diluted!
Add it directly from the bottle, mix with the growing mix, and then water the plants.
Thanks to micronutrients, iron, and magnesium, fronds are protected from yellowing!
- Easy to use and long-lasting
- Designed for palm trees and most ferns
- Promotes growth of new leaves
- Could cause burns in direct contact with leaves
3. Miracle-Gro Watering Can Singles
Determining the proper amount of fertilizer is quite tricky for some gardeners, especially for plants such as ferns, which do not need a lot of it.
If you are worried about overfertilizing your planted ferns, I would suggest Miracle-Gro Watering Can Singles All Purpose Water Soluble Plant Food, Includes 24 Pre-Measured Packets.
Now you won’t have to do the measuring on your own, since food for one feeding is packed in a single packet.
When you go to water your planted fern in a hanging basket, all you need to do is mix one packet of food with water.
- Manufacturer: Miracle-Gro
- Item weight: 8 ounces
- Package dimensions: 3.25 x 6.5 x 9.5 inches
During summer, your Boston ferns will require monthly fertilizing.
Whenever you are applying fertilizers straight from the bottle, there is a high chance of adding too much of it.
Then instead of the plants thriving on received minerals, they start slowly killing them.
Thus Miracle-Gro created single packets to help their buyers with determining the amount of food needed for one fertilizing.
Also, this pre-packed food reduces the mess sometimes created during the feeding.
This is an all-purpose food, thus the percentage of all three main minerals is the same.
As mentioned already, the well-balanced food suits ferns the most – as they do not have a high demand for minerals, the formulation with the same percentage of all minerals helps them to thrive during the entire growing period.
After planting the ferns, leave them for a few days to adjust to the new environment – provide dappled shade, as well as enough moist. Make sure that there are already some minerals in the soil by choosing the right growing mix.
When it is time for the next watering, mix one packet with water.
Never water the leaves – they are sensitive to elements commonly found in fertilizers, so always water only the soil.
There are 24 packets, which should be more than enough for the growing period.
You will notice that the recommended feeding is once every 14 days, however, this could be too much for a fern.
I would suggest tracking the plant’s health and if there is any sign of struggle, such as yellow tips, to increase the number of feedings.
In case your Boston ferns are doing just fine, continue to fertilize them monthly.
- Easy to use
- Well-balanced food
- Boosts the plant’s development
- Considering the total amount of food, it is pricy
4. Shake ‘N Feed All Purpose
Another slow-release food is this Miracle-Gro 3002010 Shake ‘N Feed All Purpose Continuous Release Plant, 8 lb, Brown/A.
As you can see this company has a wide range of fertilizers, so it shouldn’t be a problem to find the one that will suit your garden the best.
It is quite similar to the one designed for palm trees, however since it is an all-purpose one, it could be even more for your fern.
Let’s see the specification and then I will tell you more about key features.
- Manufacturer: Miracle-Gro
- Item weight: 8 pounds
- Package dimensions: 4.25 x 13.5 x 7 inches
If you liked the liquid, all-purpose food mentioned in this article at the beginning, then you can also consider trying out this one.
The NPK ratio, in this case, is different – 12-4-8, more similar to fertilizers for palm trees.
This formulation is quite suitable for a fern – it doesn’t have a high demand for minerals, and since the release of minerals in the case of this food is gradual or continuous over time, your fern might even like it more.
When grown in indoor conditions, o once you provide enough filtered sun and moist soil, the fern will thrive with these slow and sporadic feedings.
Another thing that makes this food slightly better compared to others on this list is the presence of micronutrients.
On the packaging, you can find more information about all of the minerals, and now I will just mention some of the most important ones.
Manganese and iron are present in a small percentage, but enough to ensure proper development of fronds and prevent the yellowing of their tips.
Also, these two elements could significantly help many perennial ferns which leaves are falling off every winter.
Furthermore, the food contains kelp, bone, and feather meal, as well as the earthworm casting.
Bone, feather meal, and earthworm casting are added as an extra source of minerals, while kelp is there to ensure the right development and promote the plant’s health. Many common diseases, as well as root rot, will be prevented in the process too.
This food should be added directly into the soil as well. After planting, add the food, spread it evenly, and water frequently to ensure the release of minerals.
- Contains micronutrients that enable proper development and boost the health
- Continuous release suitable for a fern
- Can burn leaves in case of direct contact
5. Jobe’s Organics
As you can tell so far, I’m a big fan of Miracle-Gro, but I wanted to include compost that is from a different company and will suit horticulturists that prefer organic fertilizers.
One of my favorite organic foods is Jobe’s Organics 09126 Palm Tree Granular Plant Food, 4 lb.
Ferns absorb minerals mostly from the soil, thus it is best to use the one with a lot of peat, bark, as well as organic matter.
If the potting mix in your hanging baskets resembles the one described above, then this organic food will suit your ferns the most.
The common problems with roots, such as rotting will be prevented due to good drainage, and additional organic matter present in the soil will boost the overall health of the Boston ferns.
- Manufacturer: Easy Gardeners
- Item weight: 4 pounds
- Package dimensions: 13 x 9 x 5 inches
One of the major advantages of this food is that it is eco-friendly.
It contains the same minerals as other ones presented in this article, but with slight improvements to make the food biodegradable and sustainable.
That environmental friendliness is achieved by adding certain types of bacteria and fungi into the food.
The organic components of the food promote the quality of the potting mix itself, while minerals ensure the right development of the ferns.
Also, additional components prevent the rotting of the root, especially when it is applied evenly around the root ball.
The NPK is 3-5-3 – it is considered for a well-balanced, all-purpose food, but this formulation suits palm trees, azaleas, and Boston ferns quite well.
Furthermore, it contains magnesium, which will promote the development of the leaves.
Almost all minerals are derived from feather and bone meal, so the release of elements is continuous over time.
So, how to use it?
The food is granular, and I wouldn’t recommend diluting it before use, since the level of the three main elements is already small.
Diluting with water might lead to mineral deficiency and yellowing of leaves.
Instead, read the instructions on the packaging – for smaller pots, one and a half a tablespoon is enough.
It is applied directly into the growing mix and spread evenly.
After a month, you can repeat the feeding.
- Organic food suitable for palm trees and ferns
- Biodegradable and sustainable
- Prevents diseases and boost the health of greenery
- Because of fungi, insects might be more drawn to your herbs
What to look for in fern fertilizer?
Even though they are not demanding plants, ferns still require that slight boost by nutrients in the fertilizer.
Only with feeding and regular watering, they can thrive indoors.
When you are picking out the fertilizer, there are a few things to be aware of. Not every plant food for indoor houseplants will work on your fern.
You have to provide them the one with the most suitable formulation and watch out for ingredients that can potentially harm the plant.
Here are the most important criteria:
1. Nitrogen level
I already talked about NPK a bit.
The optimal formulation is 20-10-20 or 20-20-20. In my experience, equal parts of all nutrients are the better choice.
You can even choose the 15-15-15 one too.
When it comes to formulation, the thing you should pay the most attention to is the amount of nitrogen.
This plant is sensitive and nitrogen burns are a common problem, so avoid plant food with too high levels of this element.
If you spot any yellowing or brown spots on the leaves, the plant food is too strong for your fern, so switch to something with lower nitrogen content.
2. Slow-release or liquid plant food
Liquid fertilizers give quicker results, but they also have to be applied more frequently, and ferns won’t respond well to overfertilization.
This type of plant food can weaken the roots over time, so your plant will have trouble fighting harsher growing conditions (for example dry air) or pests. Eventually, its health will get worse.
While there are many great liquid fertilizers available, I would try to find a similar one but with continuous release.
That one will prevent overfertilization, won’t damage the root system, and your plant will remain healthy and strong.
The type of pot in which you are growing your fern should also influence the type of fertilizer you are using.
Gardeners often use hanging baskets for growing ferns, and if you prefer these pots too, go for liquid fertilizer.
This is especially important if you are sometimes allowing your ferns to sit in the rain. It can easily wash away the slow-release plant food and eliminate the nutrients from the soil before the plant absorbed them.
Liquid fertilizer will make sure the plant is getting enough nutrients as you need to add them frequently during the growing season.
Before you click the “Order” button, take a moment to reflect on your life habits.
Are your plants your babies, or your busy lifestyle is giving you only a few hours per week to take care of them?
If the latter situation applies to you, the best choice is the slow-release fertilizer. Spikes or pellets last a few weeks, so you won’t have to worry about whether you have forgotten to feed the ferns.
5. Imitating their habitat in your home
You will get the best results if you can mimic fern’s natural habitat in your home.
So, prior to buying the fertilizer, check the soil – what nutrients are already present in the soil?
Once you know which ones the plant is getting from the potting mix, it will be easier to choose the plant food, as you will know which nutrients need to be provided through the plant food and in which amount.
Mix the soil and fertilizer evenly, so roots can access all micro and macronutrients.
How often do you use Epsom salt on ferns?
Once a month is more than enough! Around two tablespoons for one gallon of water is enough and this mixture should be added to the soil. During the growing period, keep the Boston ferns in the shade, and track the progress. If the leaves are turning yellow, you can repeat the feeding, but most likely that won’t be necessary. When the growing period ends, take a break from feeding.
With proper care, this herb can thrive in any environment and the right food will bring out its beauty even more.
I hope that, with my growing tips and recommendations, you can turn your house into a true tropical paradise.