Indoor plants need to be fertilized to help them grow to their full potential and look stunning all year round. Natural houseplant fertilizers are a great option as they are safe, effective and provide a steady release of nutrients into the soil. In addition, they are eco-friendly and will even improve the quality of the potting soil over time.
How do you fertilize houseplants naturally? Natural organic material can be used to provide nutrients to fertilize your houseplants naturally. Household waste such as coffee grounds, egg shells, banana peels and green tea are suitable, or commercial natural houseplant fertilizer can be used.
In this article, we will explain what natural houseplant fertilizer is and explore some of the different ways you can fertilize your potted plants using safe, environmentally friendly nutrient sources ranging from kitchen waste to commercial natural fertilizers. We will also look at the reasons for choosing natural over chemical fertilizers. Read on for some great tips to fertilize your houseplants naturally.
What Is Natural Houseplant Fertilizer?
Natural fertilizers are materials containing nutrients that are minimally processed, so the nutrients remain in their natural forms.
In most cases, these nutrients are organic in form and are not immediately available for uptake by plant roots, as plants can only use nutrients that have been decomposed and converted into mineral form by microorganisms in the soil.
When applied, these natural fertilizers release nutrients to plants more slowly than chemical fertilizers do. Think of it this way: Natural fertilizers feed the soil rather than directly feeding the plant.
The terms “natural” and “organic” are often used interchangeably to refer to any type of naturally occurring fertilizer.
However, some people will insist that organic fertilizers can only contain organic materials that are derived from biological matter, whereas natural fertilizers can contain both organic and mineral components.
While there are natural fertilizers that are used in the same way as the familiar commercial chemical fertilizers that you can find in any gardening supply center, the term also applies to soil conditioners (also called “improvements” or “amendments”), which need to be worked into the soil before potting your plants.
The list of natural fertilizers used in agriculture is long, but among the best are kelp, cow manure, alfalfa meal, limestone, and chicken manure fertilizers along with compost, worm castings, and teas.
However, many natural fertilizers that are great for farms and gardens are impractical for use on indoor houseplants because of the smell.
But there are many commercial natural houseplant fertilizers, as well as DIY options made by recycling food waste that can save you money while nourishing your indoor plants. The next section discusses some of the best options for fertilize houseplants naturally.
5 Easy DIY Options To Fertilize Houseplants Naturally
Fertilizing your houseplants naturally can be as simple as using kitchen and household waste to feed your plants. Whilst you can purchase excellent natural fertilizers, they tend to be more expensive than synthetic fertilizers.
Household waste doesn’t have to cost a thing and it’s a great feeling being able to put your household waste to good use growing wonderful houseplants. Here are my top 5 natural houseplants fertilizers.
Eggshells
Eggshells provide the essential plant micronutrient calcium and also help lower the acidity level of soils as a substitute for agricultural limestone.
With cleaned, crushed eggshells, you can pulverize them and mix them into the potting soil when you are potting your plants, or make a fertilizer tea that you pour into the soil by steeping them in boiled water overnight.
Banana Peels
Banana peels contain high levels of potassium, as well as small amounts of nitrogen, phosphorus and magnesium and make a great slow release natural houseplant fertilizer.
You can either lay strips of banana peel directly on the soil, cut them up into small pieces and mix with the potting soil, or puree them with water and pour onto the houseplant soil. The banana peel will decompose slowly, releasing the vital nutrients into the soil for your plants to use.
Coffee Grounds
Used coffee grounds can be mixed with potting soil, used for compost, or you can make liquid coffee fertilizer by soaking them in water for a week. Coffee grounds are high in nitrogen, but relatively lower in potassium and phosphorus, so will be better for foliage plants.
See more about using coffee grounds to fertilize indoor plants in this article, which discusses the pros and cons and the best ways to use them.
Aquarium Water
If you have a freshwater aquarium at home, you have a supply of houseplant fertilizer ready and waiting. The waste water is rich in natural nutrients from the decomposing fish food and fish waste.
When changing the aquarium water, you can apply this directly to the soil for your houseplants to use.
Using aquarium water to fertilize your houseplants actually mimics the natural nitrogen cycle. In nature, plants in and around a pond will process and make use of nitrogen waste produced by fish, helping the plants grow and filtering and cleansing the water for the plants.
This is even used in a type of agriculture called aquaponics, where fish and plants are grown in the same system, creating a mutually beneficial environment for all. Learn more about aquaponics here.
Green Tea
Green tea grounds are a great option for fertilizing acid loving houseplants such as Begonias and African Violets.
Tannic acid within the tea leaves lowers the pH and the high nutrient concentrations ensure your houseplants will grow strong and healthy.
Twice brewed green tea can be used directly on your houseplants after it has cooled or you can keep and compost the green tea leaves and grounds to use later.
Commercial Natural Houseplant Fertilizer
There are many great natural houseplant fertilizers that you can purchase as either slowly releasing dry formulations or faster-acting liquids.
Natural dry fertilizers made for houseplants may be in the form of loose granular fertilizer that you sprinkle onto the potting soil or compressed spikes that you insert into the soil. They often contain bone meal, blood meal, rock phosphate, limestone, or dehydrated worm castings.
Common ingredients of natural liquid fertilizers include liquid kelp, fish emulsion, worm tea, compost tea, and plant extracts.
Because natural matter is complex and variable, you won’t find N-P-K ratios listed on the labels of these products. But if you need a certain one of the three main macronutrients, here are the natural fertilizers containing good amounts of eachto look for:
- Nitrogen: Fish emulsion, cottonseed meal, alfalfa meal
- Phosphorous: Rock phosphate, bone meal
- Potassium: Kelp meal, granite meal
The Benefits Of Using Natural Fertilizers For Houseplants
There are many advantages to using natural rather than chemical fertilizers for your indoor houseplants:
- Gentle And Safe: Since natural fertilizers are not overly concentrated and take time to break down, the risk of burning your plants is greatly reduced, and there’s no toxic salt buildup in the soil or leaching into the groundwater
- Soil Building: Natural fertilizers with organic material improve the structure of the potting soil, increasing aeration, enhancing its ability to hold moisture and nutrients, and promoting the microbial ecosystem
- Environmentally Sustainable: Natural fertilizers are much more environmentally friendly, with organics being both renewable and biodegradable
- Affordable Options: Although commercial natural fertilizers are typically more pricey than chemical blends, you can save money by using common household items to make simple homemade fertilizers
The Problems With Using Chemical Fertilizers
As opposed to natural fertilizers, chemical fertilizers consist of highly concentrated nutrients that are extracted and refined through industrial processes.
These may also be referred to as “synthetic,” “manufactured,” or “inorganic” fertilizers. They usually contain nitrogen, phosphorous, and potassium in ratios that are listed on the packages as N-P-K values.
Chemical fertilizers are popular for use with houseplants because they are easily available, relatively inexpensive, and provide mineral nutrients that are immediately available to plants. Also, they are precisely formulated, so you know exactly what nutrients you’re feeding your plants.
But these fertilizers have some pretty big downsides involving risk of harm to plants,along with their negative impact on the environment:
- Overuse: Since the nutrients in chemical fertilizers are highly concentrated and are immediately available to plants, it’s very easy to over-fertilize, which can cause chemical burns to sensitive plant tissues
- Toxic Salts: The excess mineral salts from chemical fertilizers can build up to toxic levels in the potting soil, which will damage the roots and weaken the plant
- Soil Depletion: While they deliver nutrients to plants, chemical fertilizers do nothing to build the soil, so the potting mixture will eventually lose its organic matter as well as its microbial ecosystem, becoming compacted, lifeless, and unable to hold water or nutrients
- Environmental Damage: Chemical fertilizers are primarily derived from nonrenewable sources such as petroleum; their mining and refinement consume fossil fuels; and leached excess nutrients from chemical fertilizers are wreaking havoc on the environment
How To Fertilize Houseplants Naturally Using Commercial Products
The principles of fertilizing with natural products are the same as those you would follow using chemical fertilizers.
- Fertilize with caution. Although natural fertilizers are much safer, too much can still harm your plants. Follow the instructions for use on the product labels carefully. And remember that fertilizing when a plant doesn’t need it is worse than not feeding it when it’s lacking nutrients.
- Fertilize only when your houseplants are actively growing or flowering.
- Know your plants. Do your research and learn whether each plant is a heavy or light feeder, choose the right type of fertilizer, and dilute it when in doubt. Generally speaking, plants in lower light conditions won’t require as much fertilizer as plants that require brighter lighting.
- Dry fertilizers are typically applied less frequently than liquid fertilizers.
Why It’s Important To Fertilize Indoor Houseplants
Most plants absorb the majority of their nutrients through their root systems from the soil. In places where plants thrive, the nutrients that plants use are constantly being replaced by the decomposition of chemical compounds in organic matter and other processes.
When a plant is growing indoors in a container, however, those natural processes are missing. And as the plant uses nutrients in the potting soil, they are not being naturally replaced.
Additionally, some nutrients are leached out of the soil each time you water the plant. So unless you provide the nutrients the plant needs, the soil will become depleted and the plant will suffer.
Many thanks for reading this article on natural houseplant fertilizers. If you want more tips to keep your houseplants healthy and thriving, check out the rest of my site and my other houseplant articles.