One of the trickiest things to figure out when keeping indoor plants is how and when to fertilize them. Yes, houseplants need fertilizer, and it’s very important to use the right can and apply it the right way.
There are many options when choosing the right type of fertilizer, but we’re going to be focusing on liquid fertilizer today. Liquid fertilizer is really easy to use and extremely convenient, especially for indoor plants.
First, we’re going to get into everything you need to know about fertilizing houseplants, then we’ll dig deeper into the best way to use liquid fertilizer for indoor plants.
Table of Contents
Why Do Indoor Plants Need Fertilizer?
Plants need many nutrients to grow. At first, your indoor potted plants will get everything they need from the soil you plant them in, but the nutrients are limited since there is only so much soil available.
Think of fertilizer as a multi-vitamin for your plants. Plants get a lot of what they need from the sun, but not everything. Some minerals and nutrients are only available in the soil, which is where fertilizer comes in.
What Nutrients Do Plants Need?
There is a long list of things plants need to grow and thrive, including oxygen, sunlight, and water. When it comes to nutrients, the most important are calcium, magnesium, nitrogen, phosphorus, potassium, and sulfur. Each of these plays an essential role in plant development.
One of the main jobs of calcium is to hold the plant cell walls together and is essential for proper growth. When plants don’t get enough calcium, new growth doesn’t form properly and mature leaves begin to wither prematurely.
Plants need magnesium to make chlorophyll, which is essential for photosynthesis and plant growth. Without enough magnesium, you may see your plants’ leaves turning yellow, or the edges may turn red or brown.
Magnesium is mobile in plants, meaning it can move from one leaf to another. Because of this, older leaves may release it so newer younger leaves can use it. So, problems with a magnesium deficiency usually show up in older leaves first.
Nitrogen is a core component of the structure of plants and plays a role in metabolic processes. Plants need large amounts of nitrogen to grow, and when they don’t get enough, many things can start to go wrong.
Nitrogen deficiency leads to poor growth, and the leaves of the plant will slowly turn yellow due to a lack of chlorophyll production.
Plants need phosphorus to transfer and store energy, and it plays a huge part in photosynthesis and respiration. Phosphorus deficiencies are not always easy to pick up on because the signs aren’t as obvious as others. Look for slow growth and maturity.
Plants need potassium for photosynthesis and to perform many of the processes needed for growth and development, especially in root growth. A potassium deficiency can lead to many problems, including brown spots on the leaves. Usually, the lower leaves are affected first.
Sulfur is important for houseplants for many reasons. First, it helps them form chlorophyll. Sulfur is also essential for plants to use the nitrogen in the soil, and it is used to build enzymes, amino acids, and proteins.
This nutrient is also essential in protecting plants against diseases. If your plants have a sulfur deficiency, you may notice yellowing leaves or your plants may start to get sick.
What Kind of Fertilizer Do Houseplants Need?
These nutrients are all important, but the three primary ones are nitrogen, phosphorus, and potassium. When you look at most fertilizers, you will see an NPK number, which shows you the ratio of nitrogen to phosphorus to potassium.
For houseplants, look for something that’s in a 3-1-2 ratio or close to it. So, anything with an NPK of 11-3-8 or 24-8-16 would be acceptable.
That said, it’s important to remember that some plants are pickier than others, so it’s always good to do your research.
All About Liquid Fertilizer
Now, there are many types of fertilizer appropriate for indoor plants, but liquid fertilizer is one of the most convenient. They provide a nice balance of nutrition that gives your plants all of the nutrients we covered here as well as other micronutrients essential for growth.
Here’s how to use a liquid fertilizer for indoor plants:
1. Choose your fertilizer. As we mentioned, an NPK that’s roughly in the ratio of 3-1-2 is usually a good choice. Some people consider natural organic options the best because they stay in the soil longer and are not as harsh.
2. Dilute the fertilizer if needed. Follow the directions for the product you choose. Generally, if the product is meant to be diluted, you will use a measuring spoon and add the liquid fertilizer to water.
3. Apply the fertilizer. Again, read the directions carefully for whatever product you choose. Some liquid fertilizers are poured directly into the soil, in which case it is essential to avoid splashing the leaves. On the other hand, some products are sprayed directly on the leaves, so it’s important to read and follow the instructions on the package.
4. Reapply as instructed. Some fertilizers work in the soil for months while others last days or weeks, so make sure you use yours as intended.
As you can see, fertilizer is important for indoor plants. There are many fertilizer options, but liquid fertilizer is quick, easy, and convenient to use. Make sure you read the instructions to ensure you’re using the product correctly, and your houseplants will stay happy and healthy.