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A Guide to Fertilizing Houseplants

Fertilizing Houseplants is a vast and somewhat confusing topic for many houseplant enthusiasts. We break down the basics in this simple guide.

We all need to eat in order to grow and sustain ourselves. Plants need to eat too. Although they don’t need to be fed quite as often as we do or our household pets.

Plants eat small amounts of food daily through photosynthesis (the process of absorbing sunlight) and the nutrients they receive in the soil. Over time that nutrient will deplete and if you want large healthy plants, you will need to replenish those nutrients.

In this guide we will go over all the basic tips for fertilizing your plants to keep them happy and healthy all year long.

fertilizing houseplants

When should I fertilize my houseplants

In general it’s best to avoid fertilizing your houseplants when they are not in an active growth cycle. This is why many people choose to stop fertilizing their houseplants in the winter months. Fertilizing your plants when they are not able to use up the extra nutrients can lead to excess salt concentration.

Most people choose to fertilize in the springtime to fall. If you want to follow that schedule, a good rule of thumb is to fertilize every 3-4 weeks during spring, summer, and early fall. Depending on where you live, reduce fertilizing as the cold months approach.

If you live in a very warm climate where the winters are mild and warm, you may not need to reduce fertilizing your plants. In some areas plants will continue growing and putting out new leaves all winter long. My plants slow way down on growth during the winter. But they will still continue to put leaves out occasionally. I live in the Pacific Northwest in zone 8.

fertilizing a houseplant

How do you fertilize indoor plants?

How you fertilize your indoor plants depends on what kind of fertilizer you plan on using. Some fertilizers come in liquid form and are often diluted with water. These fertilizers can be given to the plants when you are doing a regular watering. Simply pour the recommended amount onto the soil of your plant.

Other fertilizers can come in granular form and just need to be sprinkled on top of the soil. There are also fertilizer spikes that you can push into the soil.

choosing a plant fertilizer

What is the best fertilizer to use for houseplants?

Most fertilizers will contain the same macronutrients that will feed your plants. Those macronutrients are Nitrogen, Phosphorous, and Potassium. These nutrients can be used in varying concentrations in any houseplant fertilizer. When you read a fertilizer label, pay attention to the numbers of these macronutrients. An even blend of all three is often labeled as a 10-10-10 blend.

An even blend of all three macronutrients is a great option for most houseplants. You can find higher concentration (20-20-20) or lower (1-1-1). Make sure you do your research on your plant care so you know which concentration is best for your specific plants. I actually use the 1-1-1 on a regular basis. It’s the Miracle-Gro liquid plant food.

You may choose a slow release fertilizer option. This is a fairly safe way to fertilize your plants since it slowly leaches nutrients into the soil over time. If you need to feed your plant quickly, you may want a quick release formula like a liquid. Just be sure to CAREFULLY read all of the directions.

Each fertilizer has different feeding instructions. You will want to pay close attention to these directions. Failure to do so may result in over fertilization of your plants.

large chinese evergreen plant

Can you over fertilize plants?

You absolutely can over fertilize your plants. Too much of a good thing isn’t always beneficial. Fertilizer definitely falls into that category. Too much fertilizer can quickly turn a healthy plant into a very sick and dying plant.

If you over fertilize your houseplant, you risk a buildup of salt and mineral concentrations. This can result in “burning” of the roots. A process called reverse-osmosis can happen. This means that your plant is losing moisture from the roots and the moisture is seeping into the soil. This can make it impossible for your plant to retain enough moisture and water to survive.

Some signs of over fertilization to look for include browning and wilting leaves, yellowing leaves, leaves dropping at a rapid rate, blackened and and limp roots, and little to no new growth. Occasionally you can also see a white crusty buildup of salt sitting on top of the soil.

You can do some emergency care to help combat this problem. The first thing you will need to do is remove any fertilizer that you see on the top of the soil. Carefully scoop out all of the white buildup or granular bits. Next, flush the plant with room temperature distilled water. Make sure that there is nothing blocking the drainage hole and that water is able to freely run out of the bottom.

This process is called leaching the soil and is necessary in order to save your plants. You will need to leach the soil 4-5 times to ensure that you have removed a large amount of the fertilizer. If you have foliage that has completely died off, you can cut those parts off using sterile sharp scissors.

plants in fish tank for fertilizer
Fish tank water makes great natural fertilizer!

Natural fertilizer ideas

If you don’t like the idea of using a processed commercial fertilizer on your plants, there are some great natural alternatives. I personally love to use my dirty fish tank water to give my plants a nice low dose of fertilizer. I simply use the dirty water that I take out of the tank when cleaning it. And bonus! The water gets used multiple times making this a very eco friendly practice.

Used coffee grounds make a great option for foliage heavy plants. Coffee grounds are really high in nitrogen and boost leaf health. Simply mix them into the soil when potting houseplants.

Egg shells can be dried, crushed, and pulverized to make a powder like substance. Mix the egg shells into the potting soil to give your plants a boost of calcium.

Banana peels are another great option. Since they are really high in potassium they make a great fertilizer. My favorite method is to blend used banana peels with water. You can pour it directly onto the soil or strain it first and pour the potassium rich water into the soil.

making your own fertilizer

How to make your own fertilizer for houseplants

If you want you can make your very own fertilizer for your houseplants. This recipe is very cost efficient and it’s really easy to whip up a large batch for your plants. Here is what you need:

  • 1 tsp Baking Soda
  • 1 tsp Epsom Salts (plain and not scented)
  • 1/2 tsp Pure Ammonia
  • 1 Gallon Distilled Water

Mix all of the ingredients together in a large jug. Let the mixture sit for at least an hour. Make sure you label your fertilizer and keep it up high out of reach of children and pets.

You can just pour a small amount onto the top of your plants soil once a month. This method works great for people that want to know exactly what they are fertilizing your plants with.

how to choose the right fertilizer for your houseplants-pin image
Fertilizing Houseplants is a vast and somewhat confusing topic for many houseplant enthusiasts. We break down the basics in this simple guide.

Here are a few plant fertilizers that we recommend:

Thank you so much for reading our post on fertilizing your houseplants. We really hope it was beneficial for you! If you have any further questions, leave a comment below and we will do our best to answer it for you. Happy planting! We hope your plants grow big and beautiful.

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