Ferns provide some of the most beautiful foliage out there. The fronds come in various shapes and sizes; some feature their spores prominently, while others aren’t so apparent.
Growing ferns is very different from growing a flowering plant because many are shade lovers, and one of the defining factors of a fern is that it produces spores instead of flowers.
They’re generally carefree, but with so many different kinds of ferns out there, the exact needs can vary greatly from one species to another.
Today we’re going to take a look at different fertilizer types and compare their qualities to give you an overview of what to look for when planning to fertilize any fern.
Please note that you still want to know the exact NPK and dosages for your particular fern species.
Best Fern Fertilizer
As we’ve already hunted, the particular needs of every fern are different.
However, a liquid-soluble, organic fertilizer is generally the best option for most, if not all, ferns.
Choosing an NPK
While any good fertilizer will carry a variety of micro and macronutrients, three macronutrients take precedence on the label.
An NPK ratio is the percentage of nitrogen, phosphorus, and potassium (respectively) that’s present.
These three nutrients are essential to plant growth in the following ways:
- Nitrogen is essential for healthy leaves, as well as photosynthesis and coloration.
- Phosphorus primarily encourages healthy blooms but also boosts the immune system.
- Potassium creates stronger stems and is essential for the plant’s immune system.
Oddly enough, while it might seem that all ferns would need lots of nitrogen and very little phosphorus because they don’t flower, this isn’t necessarily the case.
This brings us to the next important factor. Different plants need different pH levels and can usually handle a specific range.
Neutral pH is 6.6 to 7.3, with anything higher becoming increasingly alkaline and anything lower becoming increasingly acidic.
Most plants will do best in slightly acidic (6.1 to 6.5) to neutral since this is the natural state of most soils.
The more organic matter in the soil, the more it tends to lead towards an acidic pH, although other factors can also have a major effect on the pH.
Knowing the pH range of your plant is important when selecting a fertilizer, as this will affect the soil’s overall pH when added.
High nitrogen fertilizers add acidity, while high phosphorus fertilizers are more alkaline, although other ingredients, such as sulfur, can also have an effect.
Slow-Release vs. Liquid-Soluble
This is one of the greatest battles in plant care to this day, and it probably won’t be resolved any time soon.
Slow-release fertilizers have their advantages, such as the ability to store granule versions indefinitely. However, liquid-soluble fertilizers have a distinct advantage in terms of nutritional value.
Let’s illustrate the difference with human food.
A slow-release fertilizer is like a fruit bowl with yogurt on the side.
It will take you longer to eat, and you’ll be getting a bite of strawberry, while the next bite might be a banana, and there’ll be a bit of yogurt here and there if you dip the fruit.
Meanwhile, the juices mingle in the bowl, giving you a hint of banana on the strawberry and vice-versa.
The nutrients in slow-release fertilizers all break down at different rates, so your plant will get a mouthful of nitrogen with almost no calcium at one point. In contrast, at another, it will be mostly calcium with a hint of nitrogen.
Unfortunately, this is why slow-release fertilizers often need to be supplemented, because the plant isn’t getting the right balance of nutrition with every “bite.”
Liquid-soluble fertilizers are different and are more like a fruit smoothie.
Each sip gives you the same percentage of strawberry, banana, and yogurt as the last one, even though you can drink a smoothie much faster than you can eat a bowl of fruit.
And this is precisely what liquid-soluble fertilizers do: They break down everything at the same rate, so it’s instantly available to the plant.
For this reason, liquid-soluble fertilizers tend to be the best option for most plants, including your ferns.
Organic vs. Synthetic
And now that you’re hungry, let’s look at organic fertilizers versus their synthetic counterparts.
Organic materials break down more easily and tend to provide superior nutrition, whereas synthetic isn’t absorbed as efficiently but have a longer shelf life.
Again, we can use human food as an example and ask which is healthier: a smoothie made with fresh fruit or artificial flavoring and ground-up vitamin pills?
A Note on Compost and Manure
Of the many organic fertilizers out there, two of the most common for ferns are manure-based fertilizers and organic compost.
When added to the soil, both provide excellent nutrition when you plant or transplant a fern.
Also, you can add some at the beginning of the growing season to the top of the soil around your fern to provide an early boost, switching to a liquid fertilizer after skipping the next 1 to 2 feedings.
These two organic options work a lot like slow-release fertilizers, but they break down far more evenly and enrich the soil itself every time you water your plant.
However, they also increase the soil’s acidity, so you will want to determine first if they’re right for your particular fern’s pH requirements.
Another thing to note is that you can use both options as a liquid fertilizer by making manure tea or compost tea.
These can be added just like you would any other liquid fertilizer, although you will need to brew them overnight.
How Often Should You Fertilize?
Our last point is one that’s rather hard to pin down.
When using a liquid-soluble fertilizer, most ferns will need to be fed every 2 to 4 weeks during their growing season (usually spring through summer).
Slow-release fertilizers will generally need to be applied monthly.
However, some ferns out there are adapted to poor soils and may only need fertilizer once per year at the beginning of the growing season.
Always try to identify the species of fern you own, then check guides specific to that species.
In addition, you should always follow the instructions on the fertilizer to ensure you are giving the right amounts at the right times.
Putting It All Together
We’ve covered a lot of information, so here are the cliff notes:
- Always identify the species or cultivar of fern you own and look up a guide specific to that plant for the exact NPK ratio and feeding frequency.
- Always pay attention to any instructions on the fertilizer packaging.
- Organic fertilizers break down more efficiently and are easier for your ferns to absorb.
- Likewise, liquid-soluble fertilizers immediately give the plant what it needs, whereas slow-release fertilizers tend to break down unevenly.
- Depending on your type of fern, it may need to be fertilized frequently or only once per year.
- Compost and manure are organic options that can be used either as a liquid or slow-release but without the drawbacks of most slow-release fertilizers.