Every time an Indoor Plant is watered, nutrients leach out of the soil. Even if that didn’t happen, plants would quickly deplete the nutrients in their soil.
Unlike plants planted outside on the ground, house plants don’t have a regular source of nutrient replenishment unless you fertilize them regularly. This is the reason why Indoor plants need fertilizers to replenish the lost nutrients from the soil.
Plants growing on the ground send new roots searching for food. Here that is not possible as the area of movement and amount of soil is restricted. Fertilization will thus, ensure the growth of healthy, beautiful plants.
When to fertilize Indoor plants
Almost all house plants need regular fertilizers in the growing, flowering season. Think of fertilizers as the second half of the potting soil. When the potting soil is fresh, plants will not need fertilizers. This is especially true of modern, fortified potting soils, which often have fertilizers mixed in.
After about two months, however, the indoor plant will have consumed the nutrients in the soil
During winters, when the plants are dormant and not growing much, so do not fertilize. They do not need any fertilizer and if you fertilize you can burn or brown leaf tips.
Some of the signs an indoor plant shows when it needs fertilizer are a plant dropping its lower leaves, showing weak growth or an overall yellow-green color.
These signs are also common when a plant needs more light or less water. To analyze all conditions before feeding the plant. A good rule of thumb is to fertilize every three to four weeks in the growing season and no fertilizers in winters.
Once all danger of frost is over and just when the temperature starts getting normal in spring, fertilize your indoor plant. This is the period when the plants will shift from semi-dormant to a period of active growth.
How to fertilize Indoor Plants
Read the instructions and use 1/4th of the amount mentioned. That is because plants growing indoors will not require as much fertilizer as plants growing outdoors under the sun.
Do this once a month. Then, if the overall plant color becomes lighter, increase the fertilizer application to every two weeks.
On the other hand, if the new growth is dark green and the leaves are small and the space between two leaves on the stem becomes longer, fertilize less often.
Always follow the label instructions properly. Too much feeding can kill the plant and scorch its foliage.
In case of plants reviving from semi-dormant to a period of active growth in spring, give it half the strength of the recommended amount for the first three applications.
Types of fertilizer to use for indoor plants
Fertilizers come in several different varieties. Liquid, sticks, granular, tablets and slow-releasing forms.
The best fertilizers to opt for indoor plants are organic fertilizers as slow-releasing forms or liquid form. You can even go for solid compost form.
Sticks, pills, and tablets look cool, convenient and easy. But they don’t distribute nutrients through the soil very well. And once a fertilizer stick is inserted in the soil, you have no control over its release.
These are added to the watering can. This way, when you water, the fertilizer goes into the soil. Depending on the instructions, and the type of plant, mix the liquid once every two weeks or a month and feed the plant by watering this mixture with it.
Liquid fertilizer provides a steady stream of nutrients you which distributes well. You can control the amount of fertilizer. This way you can stop feeding in winters when plants go dormant. And start feeding again when new growth appears in spring.
This is especially used outdoors and mixed with soil. It is not preferred for container plants as they supply a lot of nutrients all at once when the pot is watered.
This makes it difficult to control the amount of fertilizer received at once. This is very inexpensive and therefore can be used for container plants but it is not a great choice.
This is the ideal fertilizer for indoor plants. It is very popular for both outdoors and indoors potted plants.
These fertilizers are quoted with time-release shells that slowly leach nutrients into the soil. The individual pellets have coatings of different thicknesses that dissolve at different rates.
The release of fertilizers is slow over a long period of time. A single application can last between four and nine months. It is quite expensive but because it lasts for so long, that evens out the expense in the end.
Organic Versus synthetic fertilizers
It is better to go for an organic fertilizer specific to most houseplants. The advantage is that these organic fertilizers for indoor plants can be applied to almost all of the houseplants.
Natural fertilizers are less likely to burn or harm your indoor plants than synthetic fertilizers. Organic fertilizers come specifically for houseplants and have a good combination of rich nutrients required for plant growth.
Organic fertilizers often use alfalfa meal, cottonseed meal or fish emulsion to provide nitrogen, bone meal or rock phosphate to provide phosphorus and kelp meal or granite meal to provide potassium.
One downside to using organic fertilizers is that they provide nutrients to the soil but these nutrients take time to break down into forms the roots can easily absorb.
One popular organic fertilizer is liquid seaweed. It is applied as a foliar spray and absorbed by the plant’s leaves.
You can also use synthetic general all-purpose fertilizers. They come with a combination of basic macronutrients that plants need to grow. They are commonly called NPK (nitrogen, phosphorus, and potassium).
Nitrogen encourages healthy foliage growth, phosphorus encourages root growth and potassium encourages bigger healthier blooms and helps the plant fight diseases.
Some of the fertilizers come specifically to a particular plant. They come in optimized proportions of these nutrients (nitrogen, phosphorus, and potassium) for particular kinds of plants. Some plants grow well with more nitrogen content while some require less of it. These fertilizers are readymade suiting particular plant requirements.
In addition to these nutrients, high-quality ready-made fertilizers also contain micronutrients such as boron, magnesium, manganese etc to encourage healthier growth.
Study the fertilizer label to determine what nutrients it contains. Whether it is suitable to make the soil acidic or alkaline depending on the plant.
Synthetic or chemical fertilizers are popular with houseplants because they are easily available, relatively inexpensive and provide mineral nutrients that are immediately available to plants. Besides they are precisely formulated.
Some of the downsides of this synthetic or manufactured fertilizers are chemical burns on sensitive plants due to overuse. The excess mineral salts get deposited over time in the soil and build-up to toxic levels in the potting soil. This weakens the plant and damages the roots.
While these synthetic fertilizers deliver precise nutrients to plants, chemical fertilizers do nothing to build the soil. This potting soil eventually loses its organic matter, as well as its microbial ecosystem, becoming compacted, lifeless and unable to hold water or nutrients.
Lastly, these fertilizers are derived primarily from non-renewable sources such as petroleum and their mining and refinement consume fossil fuels.
In the end, whichever fertilizer you choose, just make sure it is specifically for houseplants. The reason being that soil fertilizers are different and houseplant fertilizers are differently made with a combination of appropriate nutrients in equal proportions.
For example, fertilizer proportions for tomatoes are different and fertilizers for African violets are different.
Flowering plants require more of phosphorous while plain green plants without fruit or flowers need a fertilizer higher in nitrogen. Read up on your particular plant requirement and choose accordingly.
Natural ways to fertilize houseplants
There are also simple natural ways to keep houseplants healthy.
Eggshells are filled with calcium, which is important to develop a strong cellular structure. You can make eggshells fertilizer tea. Simply crush up a bunch of eggshells.
Add them to boiling water. Leave it overnight in the same water. In the morning, sieve and pour the tea right into the soil. Another way to use the eggshells is to make it a powder with the help of grinder and then mix the powder into the soil.
Add coffee grounds to the compost. You can also use brewed coffee liquid or just make a plain mix of coffee and plain water. It will nourish the plants and kill weeds and pathogens.
Brewed coffee contains a good amount of potassium and magnesium. Because of the acidic nature of coffee, this technique should be used for plants that do well in acidic conditions like ferns, roses and aloe.
green tea increases the nutrient level in the soil and improves oxygenation which helps roots thrive. The tannic acid present in green tea raises the acidity of the soil just like coffee.
Make sure your houseplant will thrive in acidic conditions. You can mix the tea leaves directly into the soil or water your plants with brewed tea after it has cooled.
Indoor plants love starch water that is left over after boiling potatoes or pasta. Just let your starch water cool and add to the soil
Banana peels are rich in potassium. Chop the peels and soak them in hot water. Let the water cool. Remove the peels and add the water to your plants
Fish Tank Water and Fish Food
Fish tank water is quite rich in many nutrients such as nitrogen and potassium which is very beneficial to houseplants. Remove some of your water from the fish tank and feed it to the plants for a nutrient-rich liquid solution.
I have personally added some fish food in my pot and seen amazing growth in case of money plant
Fruits and Vegetable Peels
keep saving your fruits and vegetable peels in the fridge. Once you have a handful of them, soak them in cold water overnight. In the morning, remove all peels and the leftover water is rich in minerals and nutrients and ready to be used for your indoor plants.
The best thing is that household waste doesn’t cost a thing and it’s a great feeling being able to put your household waste to good use.
They are gentle and safe and ensures no toxic soil buildup in the soil or leaching into groundwater. They also ensure no burning of plants and are biodegradable.
Natural fertilizers with organic material improve the structure of the potting soil and increase aeration. They improve the ability of the soil to hold moisture and nutrients.
Some Useful Tips for Adding Fertilizer to Indoor Plants
- Over time, soluble salts from synthetic fertilizers build up and create a crusty layer of salt deposits on the soil surface. Excessive salts can damage roots and make the plant more susceptible to disease attack. You can leach this salt layer away with generous amounts of water once a month. This will remove and avoid a toxic sand buildup.
- If the plant becomes wilted, water it first. Then apply a generous dose of fertilizers after it has recovered.
- There are environmental concerns regarding overfeeding the plants. These nutrient-rich solutions, when leached out, sometimes find a way to reach groundwater supplies. This leaching is mostly for pots kept on the ground and without a tray. It can happen when we take the indoor plants out in the sun and place the pot on the ground for a good wash once a month in the growing season.
- If you live in a tropical climate, where it is warm all the time, keep your houseplants on a summer fertilizer schedule year-round.
- Newly purchased houseplants or repotted houseplants should be given about a month or so and then fertilized in the growing season. Do not fertilize newly purchased houseplants in the winter season as they do not need fertilizers.
- If your houseplant is growing in the soilless potting mix then regular fertilization is important as they offer very little in terms of nutrients.
- If you notice any mold or fungus growing on your plant or soil, lower its pH with aspirin. Just crush one tablet into one quart of water and stir it until it dissolves. Then use this water to water your plants.
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