How to Fertilize House Plants Naturally

Why should you use natural fertilizers?

There are many different reasons why you might choose a natural fertilizer for your house plants. If you have pets or small children at home, you may feel more comfortable with natural fertilizers over chemical ones. Or maybe you’d like to reduce your kitchen waste and save money by using things you would ordinarily throw into the garbage bin. Whatever your reason, this list will help. Natural fertilizers are safe and effective and will help your house plants grow to their potential. Below is our guide for how to fertilize house plants naturally.

How to fertilize house plants naturally

What are natural fertilizers?

Natural fertilizers are derived from organic materials. They can be either plant-derived or animal-derived. They also provide a lot of nutrients to plants to help sustain growth. One example of a natural fertilizer is compost. Compost is organic matter which has decomposed. Lots of things can be used to make compost such as food scraps, leaves, grass clippings, coffee grounds, and much more. If you want to read more about composting and how it works, this article gives a good overview. Some other examples include kelp or seaweed meal, manure, and other animal waste that comes from meat processing.

Natural fertilizer pros and cons

Before we get into our list of natural fertilizers, it’s important to go over some pros and cons of natural fertilizers. This will allow you to make an informed decision on whether or not they’re the right choice for you and your house plants.


  • Improved soil structure – Natural/organic fertilizers improve the structure and nutrient profile of the soil by releasing nutrients into the soil. Improving soil structure will allow your house plant to retain water and nutrients better.
  • Environmentally friendly – Natural fertilizers are environmentally friendly, sustainable, and biodegradable. Synthetic fertilizers are known to runoff into our waterways which affects water quality and harms marine life.
  • Often less costly – It’s true that store-bought organic fertilizers are sometimes just as expensive or more expensive than chemical fertilizers. However, by reusing items you have at home that you would ordinarily throw away, you can save some money versus purchasing a chemical fertilizer.
  • Safer – In general, natural fertilizers are safer for use in the home and around small children and pets than chemical ones. Some natural fertilizers, such as coffee grounds, do have safety considerations though. Read more on that below.


  • Time – Natural fertilizers are a bit slower to work than synthetic ones so they require a little more patience. They have to break down the soil first in order to become effective. It could take from a few weeks to a few months to see improvement depending on your plant.
  • Varied results – Depending on your plant type, the time of year, how warm or moist the soil is, or a number of other factors, results may vary with natural fertilizers. Not all natural fertilizers work the same way or have as great of an effect as chemical fertilizers.

How to fertilize house plants naturally

Below is our list of natural fertilizers for house plants. These items are safe, effective, and cheap and you may already use them frequently in your home. Remember that for some of these, certain house plants may not respond as well as others. It all depends on many different factors including your plant type, time of year, soil moisture, etc.

Coffee grounds

How to fertilize house plants naturally (coffee grounds)

Coffee grounds have a significant nitrogen content which helps fertilize soil. They also contain a number of other nutrients such as calcium, iron, potassium, and magnesium among others. All of which facilitate plant growth. Also, using coffee grounds helps to aerate the soil. Improving aeration will help the plant’s roots to better absorb water and nutrients.

Warning: It’s important to mention that if you are going to use coffee grounds for your plants, the plants need to be in an area where your pets can’t reach them. Coffee grounds, even in small amounts, can be fatal to dogs and cats if ingested.

You have a few options on how to use coffee grounds for your house plants. You can either use them in compost, spread them thinly in the soil, or make a liquid fertilizer. We have a whole post dedicated to the use of coffee grounds on house plants including which plants they are good for and which to avoid fertilizing with coffee grounds. Check that out here.


Eggshells contain calcium which is important for the plant’s ability to manufacture new cells. They don’t provide a ton of other nutrients so don’t use them as your sole fertilizer. But they do make a great supplement to other fertilizers and they can be beneficial to any house plants.

After you crack open an egg, rinse out the shell so that it doesn’t mold. Save your shells in a plastic bag or container until you have enough for your plants (about 4 or so per plant). Then crush them with either a rolling pin, food processor, or rubber mallet if you have one. Stir the eggshells into the soil before planting or for plants already potted, sprinkle them around the base of the plant. Then mix them into the top couple inches of soil around the base of the plant.

You can also make an eggshell “tea” which will water your plants and give them some nutrients at the same time. Boil a gallon of water and add 10-20 eggshells to it. Let the eggshells steep overnight. In the morning, strain the water. Then use your eggshell tea to water your house plants.

Banana peels

Bananas, along with being a tasty snack for humans, are great for house plants too! They contain a significant amount of potassium which is one of the three major components of fertilizer (the other two being nitrogen and phosphorus).

Sometimes you will see recommendations to add banana peels straight to the soil of plants. We would caution against using this method because it may attract flies and other pests inside your house. The best way to use banana peels for your plants is by throwing them in your compost bin. However, you can also make a “tea” with them. All you have to do is put your peels into a jar, fill the jar with water, and let steep for 24 hours. Mix one cup of the tea with a gallon of water and use that to fertilize your house plants.

Green tea

How to fertilize house plants naturally (green tea)

Green tea contains essential nutrients such as potassium, calcium, and phosphorus. It works well for fertilizing plants that like acidic soil such as ferns, jade, Christmas cactus, and African violets.

After you’ve brewed your tea, let the tea bag cool and cut it open. Spread a thin layer of the tea leaves on top of the soil. If you used loose tea instead, just let the tea leaves cool, strain the water, and spread them thinly on top of the soil. You can also soak a couple of used tea bags in a gallon of water overnight and use that to water your house plants.


We touched on this a little already, but composting is a great way to add nutrients to your house plants and your outdoor garden. Lots of things can be used to make compost including food scraps, leaves, grass clippings, coffee grounds, and much more. If you want to try composting, there are a ton of resources out there to help.

Composting is more time consuming and involved than many other natural fertilization methods but if you have the time and patience, it can be very beneficial to your indoor and outdoor plants.

Aquarium water

One of the more surprising natural fertilizers that is not often thought of is aquarium water. Water from fish tanks contains essential nutrients such as nitrogen, potassium, and phosphorus (the three main components of fertilizer). If you have a fish tank, you know that basic care requires you to periodically change a portion of the water. Instead of pouring it down the drain, you can use the water from your freshwater aquarium to fertilize your house plants.

Sticking to your regular schedule for changing your aquarium’s water, use it to water your house plants. Because various chemicals are sometimes added to fish tanks, don’t use fish tank water on house plants that you are growing for consumption such as herbs.

Blackstrap molasses

Molasses has long been used as a natural remedy for many ailments. Did you know it’s good for your plants too? Blackstrap molasses is high in several nutrients such as potassium, calcium, iron, and magnesium and it encourages the growth of microorganisms. To use it as a fertilizer, you want to use unsulphured blackstrap molasses. Sulfur is sometimes added to molasses as a preservative but it kills microbes which is not good for plants.

Add two tablespoons of blackstrap molasses to one gallon of warm or hot water. Stir to combine. Let the water cool and then it’s ready to fertilize. Use this mixture every couple of weeks to fertilize your house plants naturally.

Epsom salts

How to fertilize house plants naturally (Epsom salts)

Epsom salts are high in magnesium and sulfur and can be used as a remedy for house plants that may be deficient in magnesium or sulfur. Some house plants are more likely to be deficient in those nutrients such as some herbs and roses. Epsom salts will also aid in the creation of chlorophyll which is crucial for plant photosynthesis.

If you’ve diagnosed your plant’s soil to be deficient in magnesium, Epsom salts will help. You can use them in two ways. Either add them to the soil directly (1 teaspoon per every one foot of plant height). Or you can mix two tablespoons of Epsom salts with one gallon of water. Spray the mixture directly onto the leaves for better absorption. Repeat once a month.