Nothing beats relaxing on a warm summer’s evening, sipping a mint julep or other relaxing drink and watching as your prayer plant slowly folds its leaves for the night.
While several species are known as prayer plants, the most famous are the Calatheas. Calatheas are generally easy to care for if you give them the proper lighting and use the soak-and-dry method to ensure proper watering.
But there’s one piece of care many people tend to get confused with – fertilizing.
Here’s everything you need to know when choosing and using fertilizers with your Calathea.
What Is The Best Fertilizer For Calathea Plants?
The ideal fertilizer is a fast-acting, nitrogen-rich mix complete with micronutrients.
Just remember, not all fertilizers are created equal, even if they look the same on the surface.
Liquid vs. Granular
Of all the variables when getting fertilizer, this is where people make mistakes the most.
Liquid-soluble fertilizers are fast-acting but need to be applied frequently. Granular fertilizers, on the other hand, release their contents over time and can be applied less frequently.
This illusion of convenience is why you’ll see so many websites recommending the granular approach. However, this illusion is just that – granular fertilizers are NOT good for your plant.
See, those sites forget to point out that different nutrients dissolve at different rates.
When you apply a balanced NPK, the nitrogen will dissolve at a different rate than the phosphorus, and the potassium will also have its own rate separate from the other two.
This means your Calathea will get a huge burst of nitrogen while getting almost no phosphorus at one point and the opposite at another.
This can result in signs of malnutrition or toxicity in your plant.
Liquid-soluble fertilizers don’t have this problem. They’re designed to provide just the right amount of nutrients as soon as they’re applied.
And the inconvenience isn’t actually a problem because they dissolve in water – meaning you’re fertilizing your plant while watering it.
Best of all, you can easily adjust the dosage by diluting the fertilizer, allowing you to fine-tune the dose to fit an individual plant’s unique needs.
The Best NPK Ratio
When you buy fertilizer, the big NPK rating is the first thing you’ll see on the package. These three macronutrients are essential for plant health but focus on different areas.
- Nitrogen (N) is the most important nutrient for big and healthy foliage.
- Phosphorus (P) is primarily used in flowering but also has benefits in other areas.
- Potassium (K) has similar effects in plants as in humans, i.e., it promotes stronger stems and a healthier immune system.
Note that too much phosphorus will leech potassium out of the soil, so it’s important to ensure there’s some potassium present unless going for a specialty fertilizer such as 5-0-0 nitrogen fertilizers.
And that brings us to the ratio.
Prayer plants need big leaves and strong stems but aren’t known for their flowers, so a liquid-soluble fertilizer with a ratio of 3-1-2 is perfect.
This includes multiples of this ratio, such as 6-2-4 or 12-4-8. Remember, the higher the numbers, the more you’ll have to dilute them.
Other Nutrient Needs
The NPK is all important, but these are only three macronutrients your Calathea needs.
The other three are calcium, magnesium, and sulfur.
It also needs trace amounts of several micronutrients, which are:
Be sure to check the packaging to ensure all of these nutrients are present in the fertilizer.
Dosage and Frequency
There’s a little trick when fertilizing plants that is rarely mentioned: Always make the first and last dose of the growing season ½ as much as normal.
This is like a gentle wake-up call and a soothing bedtime story for your plant.
Calatheas grow during the spring and summer, slowing down in the fall and laying dormant through the winter.
Thus, when you see the first signs of new growth in early spring, you’ll give your half-strength dose, and at the end of summer, you’ll give another half-strength dose.
But there are two different frequencies to keep in mind.
The first will mean feeding your Calathea a full dose every 8 weeks throughout the growing season.
The second is half-strength every four weeks (with the first and last dose being ¼ full strength).
We recommend the second option, as your prayer plant will be at less risk of an overdose.
Also, if you have just repotted your Calathea for any reason, you will want to skip using fertilizer for a month so the roots have time to settle in.
Sometimes your plant needs a little more nutrients than your fertilizer provides.
Thankfully, there are three very common supplements available to help out when you need to give the prayer plant a little boost.
- Used coffee grounds are surprisingly useful.
- Rich in nitrates, they can be sprinkled onto the soil to give it a boost of nitrogen.
- Oddly enough, this nitrogen isn’t usually consumed by the plant itself.
Instead, beneficial nematodes and other microscopic life on nitrates will target the grounds, allowing your plant to consume the nitrogen already present without competing.
This is a very simple recipe that provides a calcium boost your plants can easily absorb.
Rinse out some fresh eggshells and add them to a pot of water.
Bring the pot to a boil, then reduce the heat to a simmer and allow it to sit overnight.
Strain out the eggshells, and the resulting calcium-infused water can be added the next time your plant’s thirsty.
Most often used as a soak for sore muscles, Epsom salts are a natural magnesium-based compound that can be very healthy for plants.
It only takes 1 teaspoon of Epsom salts to give your Calathea a huge magnesium boost.
On a final note, we should address the risk of fertilizer burns and overdoses.
Getting fertilizer directly on the plant can cause chemical burns, which will need time to heal.
Additionally, fertilizers contain mineral salts, which are harmful to plants in large concentrations.
Mineral salts naturally wash away outdoors but will build up in the soil of potted Calatheas.
You can mimic the natural leaching process by flushing your plant every few months, and regular repotting will also remove the excess salts from around your plant’s roots.
While not particularly harmful in small amounts, mineral salts will choke a plant’s roots in higher concentrations, preventing them from absorbing water and nutrients and sometimes resulting in chemical burns to the root system as well.
If you suspect your Calathea may have had too much fertilizer, skip the next session and consider flushing the soil.
In extreme cases, don’t hesitate to change out the soil, even if it’s not the usual repotting time.