Plant Food: Why Houseplants Need Fertilizer

* Image sources: All images used in this post are from the author

Giving your houseplants a good fertilizer is like treating them to a gourmet meal—they thrive on it just like we do! After all, who could resist pampering these green beauties with some nutritious goodness? Nevertheless, one can also easily go overboard in a fertilizing frenzy.

In natural ecosystems, rainfall and organic decomposition replenish soil nutrients and wash out toxins. However, potted houseplants lack access to these processes. Fertilizer serves as their nutritional sustenance, compensating for the absence of natural replenishment.

Even though I am not a fan of overly fertilizing indoor plants, it is still necessary to know a little bit about why your plants need fertilizer at all as well as how to avoid using to much or too little of it. That said, you can already keep in mind that with fertilizer, less is more! You will see why this is the case in this post!

Is It Necessary to Fertilize Houseplants?

In nature, rainfall and the organic cycle of leaves and other organic material decomposing rejuvenates the soil regularly, providing new nutrients while washing out toxic build-ups. The plant roots extract nutrients from the soil, the natural cycle provides new nutrients.

Your houseplants though, live enclosed in a pot.

By putting them in a pot, we as plant parents are responsible to mimic their natural habitat and cycle best we can. As the soil doesn’t naturally refill with nutrients, we use fertilizer when watering them to provide our houseplants with the necessary nutrients to stay healthy and grow well. The fertilizer is the food you feed your plants.

Reading recommendation: Do you want some in-depth knowledge about what your plants actually need and what nutrients are most important for their well-being? Explore all that plants need in my post linked here to better understand the life of your green fellows!

There certainly are plant parents who instead of fertilizing opt for a yearly repotting of the plant in fresh, nutrient-rich soil. Even though I do think this is a healthy option in terms of nutrients, it is not ideal for a plant to be repotted each year as this is quite a strenuous process for the plant. Thus I don’t think one can completely avoid fertilizing.

What Happens If You Don’t Fertilize Plants?

If you don’t fertilize your plants, over time, the soil will lack nutrients and the plant will starve. I would like to note here though that it takes a very long time for a plant to starve because of lack of nutrients. Especially if you repot your houseplants every two years or so, the fresh soil gives them fresh nutrients they can feed on for quite a while.

Lack of light or lack of water (or too much water) leads to much faster plant death than lack of fertilizer.

Still, lack of fertilizer over time can show its signs such as very slow or no growth of the plant, browning of the leaf tips, or eventually also wilting and yellowing leaves.

To spot any signs of illness, pests, or improper fertilizing or watering, it is best to integrate a regular health check to your plant care routine. Here are some easy steps with which you can check on your houseplant’s health.

How Often Do I Need to Fertilize My Indoor Plants?

How often should you feed your plants with liquid or granular goods? (Image source: author photo)

In my personal experiences, I’ve noticed a common tendency among plant owners to fertilize their plants excessively or too frequently, all in an earnest effort to promote faster, stronger, and healthier growth of their green pets.

With fertilizer though, it is always better to use a little less than you think the plant needs. The same goes for watering. Most people tend to overwater their plants, soaking them instead of letting the soil dry out in between which is what most common houseplants prefer.

Tip: Are you worried about overwatering your plants? Here’s my complete guide on how to water your houseplants with plenty of advice to avoid overwatering!

Most fertilizer is needed in spring when the growth season of the plants starts, and because the no-fertilizer period in winter may have leached out some of the remaining nutrients. In spring, I recommend fertilizing every two weeks with the indicated dosage. Throughout summer, fertilizing half the indicated dosage every 2-3 weeks is enough.

In winter, it is best to stop fertilizing or to use at the max one quarter of the indicated dosage every two months or so. The watering rhythm decreases as well in winter, so that works out just fine.

I also recommend using organic fertilizers. There are also plenty of organic substances which you can add to plant water as natural fertilizers. Most of them are common in any household. Intrigued? I have summed up the most effective natural ingredients for plant water in my post linked here, including the pros and cons of each.

Can You Over-Fertilize Houseplants?

You can indeed over-fertilize your houseplants. Overfertilizing is actually, along with overwatering, the main enemy houseplants face. The caring plant parent might think that more fertilizer equals more growth and hence is only beneficial for the plant. But just as with human food, too much of it causes metabolic problems.

Fertilizer is full of all the good nutrients your houseplants need but it is also a concentrate. Using it too often or too much of it can cause a fertilizer burn. How do you recognize this? Yellowing or dry edges of leaves are what is called fertilizer burn (it looks as if the rims have been burnt, just like when you light a piece of paper and it starts to get these burnt edges).

Another very clear sign of a fertilizer overdose is white salt build-ups on top of the soil. This is probably the most clearly identifiable sign and it illustrates the harmful effect overfertilizing has on the soil: Fertilizers contain lots of salts, which in low doses are needed by the plant but in high doses cause an effect called reverse osmosis. In short, too much salt in the soil hinders the roots from taking in any nutrients at all.

In this image, you can see how the soil turns white due to fertilizer build-ups. It looks as if the soil is covered by a layer of mold. (Image source: author photo)

To prevent over-fertilizing your plants, always check the dosage indicated on the bottle and stick to that. Usually, even less of the indicated dosage is enough. I recommend using only about half the indicated amount to avoid over-fertilizing your plants.

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