Plants have a very innovative system to produce the nutrients they need through photosynthesis. However, photosynthesis alone cannot produce leaves, flower buds, and fruits. Therefore, they grow by supplementing their growth with nutrients from the ground.
However, because indoor plants are grown in pots, the amount of nutrients available in the soil is limited, unlike in the natural world.
If you leave them alone to grow as they do in nature, you will not be able to appreciate their beautiful foliage and flowers. It is essential to manage them with regular fertilizers.
So, what kind of fertilizer should you apply? And when should you give it to your plants?
In this article, I will introduce the types of fertilizers for houseplants and how to feed them with the right kind of fertilizer.
What Are The Essential Fertilizers “N, P, And K” For Houseplants?
There are three types of fertilizers required for houseplants: nitrogen (N), phosphoric acid (P), and potassium (K), and they are the main meals in human terms. They are the nutrients that are needed the most.
Nitrogen (N) is needed for leaf and stem growth, phosphoric acid (P) for flower and fruit formation, and potassium (K) for root growth.
In addition, there are 11 other necessary nutrients, such as calcium and iron. However, these are in small amounts and are not considered fertilizers. Therefore, they are supplemented with fertilizers.
Types of Fertilizers for Houseplants
Even if you know about the nutrients your houseplants need in fertilizers, the story is different regarding the types of fertilizers.
Many types of fertilizers are sold on the market, and it isn’t easy to know which one is best for your houseplants.
Fertilizer types, ingredients, shapes, and sizes vary from manufacturer to manufacturer. However, if you know roughly about fertilizers, you can choose the right one.
Here is a detailed explanation of the different types of fertilizers.
- Chemical fertilizers
- Organic fertilizers
- Liquid fertilizers
- Organic Chemical Fertilizers,
To begin with, there are two main types of fertilizers: chemical and organic. Knowing these two types allows you to choose the appropriate one for your potted ornamental plants, flowers in your flower beds, and vegetables in your garden.
Chemical Fertilizers Are High In Ingredients And Fast-Acting
Chemical fertilizers are often used for commercial potted plants and as base fertilizers (when preparing for planting).
Since they are manufactured from inorganic materials by man, they have many fertilizer ingredients (nutrients), and their ingredients are precisely adjusted.
For example, fertilizer packages are often labeled “N:P:K = 10:10:10” to indicate that the ratio of ingredients is balanced and even.
Most of them are white solid types and have the characteristic of dissolving into the soil rapidly. However, since they are synthetic, their dissolution speed can slowly be effective for some if you choose the right type.
Advantages and Disadvantages
The advantage of chemical fertilizers is that they can put more nutrients into the soil at one time and send nutrients to plants faster than organic fertilizers.
They are also easier to formulate, making it possible to fine-tune the balance of nitrogen, phosphate, and potassium in the fertilizer.
In addition, it does not emit gases easily, so it has no odor and does not attract flies and other insects.
However, since the ingredients are made of inorganic substances, they are not friendly to soil where microorganisms live.
There is a demerit of continuing to apply chemical fertilizers, which kills the microorganisms and hardens the soil. In addition, overfeeding may cause growth problems.
Moreover, microorganisms in the soil help plants grow and build disease-resistant systems. Therefore, the absence of microorganisms in the soil may be difficult for plants.
Organic Fertilizers Are Gentle on The Soil And Effective For A Long Time
Organic fertilizers derived from animals and plants are gentle to the soil and allow microorganisms to live in the soil and grow plants more healthily.
They are available in powder, granular, and pellet types, and by applying them to the soil, the microorganisms become active, creating well-oxygenated, soft, and fertile soil.
Also, since microorganisms break down organic matter over time, the fertilizer ingredients reach the plants slowly, and the effect lasts longer than chemical fertilizers.
There are several types of organic fertilizers, both plant- and animal-derived. Here are the main types and characteristics of organic fertilizers.
|Oil cake||Nitrogen (Phosphate and Potassium are also in small amounts)||Slow-acting|
|Bone meal||phosphoric acid||Slow-acting|
|Fermented chicken manure||three elements||Slow-acting|
Advantages and Disadvantages
Organic fertilizers are made of soil-friendly materials and do not inhibit the growth of plants even when over-fertilized. Since it makes the soil more fertile, it creates an environment that makes plants easier to grow.
However, one disadvantage is the smell. As microorganisms decompose organic matter, they produce gases that give off a distinctive odor.
In addition, those using animal waste have a smell of their own, which can attract flies and other insects.
Also, unlike chemical fertilizers, it is difficult to adjust the ratio of fertilizer components, so the balance of nitrogen, phosphoric acid, and potassium could be better. Depending on the purpose, buying more than one type may be necessary of fertilizer.
Liquid Fertilizers Are Recommended For Potted Plants
Liquid fertilizers contain fertilizer nutrients in liquid form. You can use liquid fertilizers to supplement watering, and they can be applied without much effort.
It is suitable for pot plants, which are more challenging to dry out than plants in the ground because it works best when the soil fully absorbs it.
Advantages and Disadvantages
Unlike solid chemical or organic fertilizers, liquid fertilizers are fast-acting because the fertilizer content is already dissolved in water. You can give it as an alternative to watering, and it is less likely to damage the roots due to fertilizer burn.
However, once the water dries up, the effect of the fertilizer wears off, so the effect will not be long-lasting.
Planting in the ground, such as in fields or flower beds, is ineffective because the water runs deep into the ground before the roots absorb the fertilizer.
Therefore, you need to feed the soil regularly, which is a disadvantage that increases the management effort.
Suppose the soil has high water and fertilizer retention properties. In that case, it will not dry out quickly, and nutrients will not flow easily, so it is recommended to use it in combination with liquid fertilizers.
Organic chemical fertilizers are made by mixing organic and chemical fertilizers. Since it has both advantages, it can provide plants with nutrients efficiently without deteriorating the quality of the soil environment.
This fertilizer is recommended for those concerned about the growing environments and who want to grow beautiful and healthy houseplants.
Advantages and Disadvantages
Organic chemical fertilizers have a good balance of fertilizer components. Some products are available in both fast-acting and slow-acting types, making them easy to choose from.
They are all-purpose, as they can be used not only for houseplants but also for garden plants, flowers, and even vegetables and fruit trees.
However, they are relatively expensive among fertilizers and may cost extra. It may be suitable for those who grow houseplants at home but not for those who have a vegetable garden or gardening.
How to Choose Fertilizers for Houseplants
In general, you can feed your houseplants any fertilizer you want.
But plants are grown so that their leaves and flowers can be admired. Therefore, plants with too little nitrogen and phosphorus may be less effective, depending on the type.
Additionally, when a plant blooms or bears fruit, it directs its limited resources toward that part of its growth. As a result, the leaves may lose color or shrink in size.
Even feeding high phosphate fertilizers will only promote flower and fruit growth, resulting in less appealing leaves.
You can have beautiful leaves on your houseplants if you know how to choose the right fertilizer.
Here’s a quick look at how to choose a fertilizer for houseplants
1- Consider The Use Conditions And Purpose
The best way to choose the right fertilizer for your plants is to select the kind that works best for the circumstance and goal.
A primary fertilizer is used to prepare the soil for planting, while a secondary fertilizer is applied to the plants at the beginning of the growing season.
Excessive fertilizer application during top dressing to compensate for lack of fertilizer application during soil preparation risks burning the plant and negatively impacting its growth.
If you haven’t heard of it, top dressing is when fertilizer is spread on top of potting soil to give it a steady supply of nutrients.
Furthermore, depending on the shape and size of the fertilizer, some are intended for houseplants, while others are designed for garden plants. If you make a mistake, you may end up over-fertilizing your plants.
You need to research and find the best fertilizer if you want healthy houseplants. Some fertilizers are available for ornamental plants, and some are specially formulated fertilizers for popular plant varieties.
2- Select Either Chemical Or Organic Fertilizers
There are two kinds of fertilizers: chemical and organic, and each has advantages and disadvantages.
Chemical fertilizers have no odor and are easy to handle in any location, but they are unsuitable for long-term use.
On the other hand, organic fertilizers produce odor but can provide a suitable environment for plants in the long run.
Frankly, it is a matter of personal preference, and you are free to choose. However, you can combine the two depending on where you live and the time of year.
Use organic fertilizers, which smell different and tend to attract insects. You can only use chemical fertilizers from May to August when insects are more likely to be outside and less likely to come inside.
Also, chemical fertilizers are easier to use in apartments because they don’t smell. On the other hand, organic fertilizers are easier to use in houses with backyards.
Consider the problems you might have after using the fertilizers before making your choice.
3- Check The Ingredients List
Check the ingredients on the package once you have decided on the fertilizer’s intended use and type.
Different types and products have different amounts of nitrogen, phosphoric acid, and potassium.
Choose the one that best suits your needs, such as which part of your houseplants you want to grow well, whether you want them in balance, or whether you want one bag to feed multiple plants.
Chemical Fertilizers Are Recommended For Houseplants
So, what is the “right fertilizer for houseplants”?
If you are growing houseplants in pots, the author recommends using a small chemical fertilizer that contains a good balance of the three essential plant nutrients.
If you keep applying it for a long time, the microorganisms will be eliminated, and the soil will gradually harden. Plants grown in pots, on the other hand, should be repotted every two years.
If you repot at this interval, you can replace the soil with new, soft soil before it becomes too hard, causing less stress to the plant.
Furthermore, using a soil medium for houseplants eliminates the need for a base fertilizer when planting.
It is also recommended that liquid fertilizer be applied with water only during summer.
When and How to Apply Fertilizer for Houseplants
Indoor plant fertilization adheres to a few basic guidelines.
- Feed your indoor plants in the spring and fall.
- Adjust the amount of fertilizer to be applied.
- Apply fertilizer based on its type and shape.
1- Feeding in Spring and Fall
The growing season for many plants is at its peak in spring and fall, when temperatures are warmer. They need a lot of nutrients at this time of year, so you should feed them regularly with fertilizers.
However, some houseplants in tropical and savanna regions may reach their growth stage in summer.
The growth process may differ in detail depending on the type and variety, so it is a good idea to research the growth of each species before applying fertilizer.
2- Adjusting the amount of fertilizer
When you apply fertilizer to houseplants, be sure to measure and use the correct amount. The wrong amount of fertilizer may cause the plants to grow stunted and need to be more effective.
If you’re worried about using too much fertilizer, follow the instructions on the package and use half the amount they recommend. It would be enough, and your plants would be safe.
Also, please follow the dilution amount indicated on the package for liquid fertilizers.
3- Use According To The Type And Shape of Fertilizer
To get the best results from using fertilizers, whether as primary fertilizers (when preparing the homemade soil mix) or as top-dressing, selecting a fertilizer type and application method tailored to the plant’s specific needs is crucial.
When using fertilizer as a top dressing, spread it on top of the soil and be careful not to let it directly touch the plants.
For winter fertilizers, we recommend small granule-type fertilizers with a coating on the surface so that they work slowly and for a long time.
Since they do not readily dissolve in water, plants will gradually absorb the fertilizer components throughout the winter and be ready for spring.
Besides growing olives or eucalyptus indoors, grow them as garden plants. I recommend burying about four large granules of solid-type fertilizer around the plant for garden trees.
Tips for Using Fertilizer to Get the Best Result
Use organic compost and Sawdust
You should use organic matter-rich compost for the soil where you grow your houseplants. The presence of microorganisms makes it easier for the plant to replenish nutrients, and the soft ground makes root rot less likely.
Furthermore, because compost is a fertilizer, the plants will grow well without additional fertilizer.
Humus, bark, and cow manure are all examples of organic composts. The best organic composts to use indoors are humus and bark composts, which come from plants and don’t smell too bad.
Also, compost should be as entirely aged as possible. Compost that is too cheap is not fully ripe and will gradually ferment and heat up after use, potentially damaging the roots.
If you are concerned about odor or fly infestation, cover the soil surface with a 1-2 inch layer of Sawdust or something similar to eliminate the foul smell.
Repotting Every Two Years
Once every two years, you should repot your houseplants and give them a basal fertilizer and a top dressing.
A basal dose is not required if you use a ready-made soil mix for houseplants. Basal is only used if you are creating your soil.
If you do not repot at all, the soil in the pot will become old, and nutrient deficiencies will occur, weakening the houseplant. As the plant gets weaker, it becomes more vulnerable to pests and diseases, and the risk of dying increases.
Also, fertilizer can kill the plant, so it’s best to repot it before the roots fill the pot.
Combine Fertilizer Application With Supplement
Plants cannot thrive on nitrogen, phosphate, and potassium fertilizers alone.
In addition to the three fertilizer elements, plants require three secondary elements and eight essential trace elements.
The plant thrives when all nutrients are present and becomes robust and wither-resistant.
Use a supplement to add nutrients beyond the primary three that come in fertilizer. You can use these extra supplements to make up for nutrient deficiencies at any time of the year.
For instance, if the veins of your plant’s leaves are green but the leaves themselves are turning yellow, your plant may suffer from iron deficiency. Therefore, you need to use soluble chelated iron so plants can absorb it.
|Macronutrients (Requires in Large Amount)||Secondary nutrients||Micronutrients|
Phosphoric acid (P)
|Calcium (Ca), |
Add a supplement containing other trace elements to the fertilizer you use to feed your houseplants. As a result, the foliage on your houseplants will change to a more appealing appearance.
Digression: Silica Gel Can Be Used As A Fertilizer
Silica gel (SiO2), commonly used as a food desiccant, is also used as a fertilizer in farming.
Silica gel contains silicon (Si), also known as silicon dioxide. Silicon is not a nutrient required by the plant, but feeding it strengthens it.
Plants that absorb silicon have more cellulose cells, making them more resistant to pests and diseases and allowing them to grow into more robust plants less likely to fall over. Silicon is sometimes used to grow lawns and rice because it helps plants grow, especially rice plants.
For houseplants, a chemical fertilizer with a good nitrogen, phosphate, and potassium balance is recommended, and regular repotting will help prevent soil deterioration.
If you have difficulty selecting a fertilizer, consider the growing conditions and the purpose for which it will be used, and then select the appropriate one.
Also, you may overfeed them because you have a particular affinity for your plants. However, too much fertilizer can worsen the plant’s growing conditions and weaken it.
You should fertilize in spring and fall, before and after flowering, and before and after new shoots and flower buds appear.