Plant Food Is Not Fertilizer, Here’s the Difference


You know you’re supposed to fertilize your plant every now and again, or wait, does that mean you should give it plant food? After all, they’re kind of the same thing, right? That’s what you’ve always believed, and now you want to know if you’re correct. We did a lot of research to provide you the answer.

What’s the difference between plant food and fertilizer? The main difference is that plant food is a naturally occurring type of sustenance while fertilizer is not. Plants make their own food for survival. Fertilizer delivers nutrients for survival as well, but commercially, not naturally.  

Plant food is not the same thing as fertilizer and vice-versa.

If you’ve always thought that plant food and fertilizer are two interchangeable terms, that’s okay. So too did lots of gardeners, at least at the start of their journey. In this article, we’ll help correct any misconceptions, defining both plant food and fertilizer. Then we’ll dive deeper into the differences between the two.

What Is Plant Food? What Is Fertilizer?

As we said, let’s get started with some definitions. This will explain a bit more about how plant food and fertilizer aren’t the same.

Plant Food

Your houseplants get watered regularly, but they need more than H2O to survive. They also require plant food.

Your indoor plants are pretty smart, in that they have the ability to make food themselves. Another term for this? Photosynthesis. Well, it’s one function of photosynthesis, anyway.

Your plant will begin making food through a combination of sunlight (which provides energy), carbon dioxide, and water. You give them sun and water, and the houseplant gets carbon dioxide through the air in your home or apartment.

The carbon dioxide gets within the plant via its leaves and interacts with chlorophyll or leaf pigment. The result is a food consisting of carbohydrates and sugar, with the latter made by the chlorophyll’s chloroplasts. When you water your houseplant, soil minerals and the newly-made sugar travel, keeping the plant healthy.

When the plant combines the nutrients it already has with its food, it can make vitamins, enzymes, and protein.

Fertilizer

Macronutrients and micronutrients keep a houseplant alive. (We’ll talk about these later in the article, so keep reading!). To fill in any nutrient gaps your plant has, there’s fertilizer. This can also supplement certain nutrients in the houseplant’s soil so there’s no risk of a deficiency.

Fertilizer comes in both natural and synthetic forms. As the name might imply, natural fertilizer only derives its ingredients from natural sources. These may include poultry manure, fish waste, seaweed, blood meal, bone, feather meal, and cottonseed meal. The most important trait of this fertilizer is the microorganisms within.

These microorganisms may include biological compounds, fungi, algae, or bacteria, any of which helps your plant thrive. The microorganisms need a soil temperature of at least 50 degrees Fahrenheit, often higher, to work their magic.

Your other option is synthetic fertilizer. This has no natural ingredients; in fact, it’s mostly made of liquid ammonia. The rest of the product may consist of filler or ballast. Most of the time, if you look at the label, you can see the ratio of nutrients contained in a synthetic fertilizer. Depending on which nutrient your houseplant needs the most, you’d want to shop carefully to buy a fertilizer with a good quantity of that nutrient.  

The Differences Between Plant Food and Fertilizer

Now that you have a better understanding of both plant food and fertilizer, let’s explore more differences between the two.

Plant Food Is Always Naturally Occurring While Fertilizer Is Not

This is the point we brought up in the intro. Houseplants will make their own food. They need water and sunlight from you to kickstart the process, but that process itself is entirely natural. It’s photosynthesis, remember? You don’t have to use any chemicals or foreign products to trigger your houseplant into making plant food. It will do it when necessary. If by chance it doesn’t happen, that would likely mean there’s something wrong with your plant.

Fertilizing isn’t a naturally occurring process. Yes, you can buy natural fertilizer, but houseplants don’t fertilize themselves. It’s something you have to do for them.

Fertilizer Is Commercially Available

On that note, you cannot buy plant food commercially. Okay, if you did a Google search right now for plant food, you would get lots of products that claim they’re plant food. Are they? More than likely, these products act as a type of fertilizer.

However, no matter what a product label says, the plant food we’re talking about in this article is the naturally occurring kind that houseplants make on their own. It’s not something you can label and sell, unlike fertilizer.

Houseplants Will Make Plant Food More Often Than You Need to Fertilize

How often does a houseplant produce its own variety of plant food? It depends, but it has to be semi-often since nutrients deplete, so maybe every couple of weeks and maybe even more often than that. You will not fertilize your houseplant nearly that regularly, or at least, you shouldn’t.

Admittedly, it does vary by houseplant, but for the most part, you should fertilize on a three-month schedule, maybe even four months. We’ll talk more about overfertilizing later, so make sure you don’t miss it.  

Micronutrients vs. Macronutrients

Okay, we’ve mentioned micronutrients and macronutrients a few times throughout this article, but what are these?

As we said before, your houseplant relies on both micronutrients and macronutrients for its survival. These nutrients can promote growth and keep your indoor plant healthy, strong, and happy. There are a lot of both nutrient types, with up to 16 macronutrients critical to your plant’s health.

Let’s talk first about micronutrients and then macronutrients.

Micronutrients

The following micronutrients should be a part of your houseplant’s “diet:”

  • Cobalt: If you just settled your houseplant somewhere, then it may need more cobalt than it will at other times in its life. This micronutrient will allow for nitrogen fixation and aide in establishment in a new pot or environment.
  • Zinc: To control sugar consumption and ensure carbohydrates become food, make sure your houseplant gets zinc. This can include zinc chelate, zinc sulfate, or zinc oxide. Through these sources of zinc, your plant could experience growth as the enzyme systems get fed.
  • Molybdenum: Without molybdenum, your houseplant cannot regulate nitrogen usage. This micronutrient also allows for sulfur and oxygen to cycle.
  • Manganese: To maintain your houseplant’s nitrogen metabolism, it needs manganese. This nutrient causes carbs to break down in conjunction with the plant’s enzyme systems as well.
  • Iron: We talked about the importance of chlorophyll when it comes to a houseplant generating its own source of food. Well, without iron chelate or iron sulfate, your plant lacks the chlorophyll it needs.
  • Chlorine: Another major plant process that any healthy houseplant should do is photosynthesis. Thanks to chlorine, photosynthesis is possible.
  • Copper: With copper, your indoor plant can use its proteins to the fullest potential. Besides that, the micronutrient boosts the metabolism of the roots and helps the plant in reproducing.
  • Boron: As a nutrient regulator, boron plays a big role in your houseplant’s health. From borax to organic matter, boron promotes the growth of fruit and seeds (only in houseplants capable of producing these, of course) and helps you plant make carbs and sugar.

If you’re using the right type of soil for your indoor plant, then it should get all the micronutrients it needs from that soil alone. There are exceptions, such as if you mix your potting soil or soil media by hand.

Macronutrients

The big three macronutrients are potassium, phosphorus, and nitrogen, but there are plenty of others. Let’s talk about them all now:

  • Sulfur: Although not one of the three major macronutrients, sulfur does a whole lot for your houseplant. It keeps your plant able to withstand cold temperatures (to a degree), generates growth, helps your plant make more seeds and grow stronger roots, and it creates chlorophyll. Further, without sulfur, your houseplant cannot produce any vitamins, enzymes, or protein.
  • Magnesium: Found within the chlorophyll of your houseplant is magnesium. Your plant couldn’t photosynthesize without it. Whether you use Epsom salt, dolomitic limestone, organic material, or soil mineral to get your magnesium, it will trigger growth enzymes in the plant.
  • Calcium: Through superphosphate, gypsum, and dolomitic lime, calcium can work wonders on your indoor plant. For instance, it lets nutrients travel while supporting the structure of cell walls within the plant.
  • Potassium: Potassium can safeguard your houseplant from damage caused by critters and pests, temperature fluctuations, and drought. With less stress, your plant should survive longer. It will mostly absorb this macronutrient.
  • Phosphorus: Yet another nutrient that plays a vital role in photosynthesis is phosphorus. Further, it leads to growth in the roots, encourages plant blooming and maturation, and aides in the transition of solar energy to chemical energy. Your plant can even handle stress better with phosphorus, be that its superphosphate, bone meal, or fertilizer forms.
  • Nitrogen: Most importantly, your houseplant needs nitrogen. Without it, your plant cannot do anything with the energy it creates. Nitrogen chiefly allows photosynthesis to happen, but it also lends itself to the production of chlorophyll and energy transfers within the houseplant.

What Happens If You Overfertilize Your Houseplant?

Whether you wish to catch your houseplant up on its micronutrients and macronutrients or you’re concerned about a deficiency, you may have overdone it on the fertilizer. You certainly fertilize more than every three or four months.

How will you know something has gone amiss? Well, for one, take a look at the color of your houseplant’s leaves. Have they turned yellow? That could be one indicator of overfertilizing. You may also notice the houseplant has wilted, the leaf margins look dried or burned, and the plant doesn’t grow as quickly as anticipated. Oh, and your indoor plant could die, too. That’s as clear a sign you need that you made a critical error.

Even if your indoor plant does survive, overfertilizing can cause an accumulation of salt. Your plants may not be able to absorb water as easily thanks to all this salt, which settles on the surface of your plant’s soil. If you flush the houseplant through with sink water several times (like three or more), you can get rid of all the salt buildup. Your plant should be good from there.  

Related Questions

Is compost the same as plant food or fertilizer?

Compost is not fertilizer, and it’s not exactly plant food, either. That said, you can use it as a form of plant food since it contains the nutrients your houseplant needs. Depending on what your compost consists of, it could have more than a dozen of the nutrients that will support a healthy houseplant.

You can make compost yourself using materials you already have lying around at home. For instance, try dried leaves, newspaper (rip or shred it first, please), kitchen waste, yard trimmings, or grass clippings for your compost. The key is letting decay take place over one to three months.

Does soil pH matter when it comes to your houseplant getting nutrients?

You probably learned about pH in science class, but you might not remember much these days. That’s unfortunate, because despite you fertilizing your houseplant only when needed, it doesn’t seem to be doing well. Why is that?

The pH of your soil absolutely matters when fertilizing your houseplant. First, a little lesson. pH is a measure of whether a solution is more basic or acidic. The higher up you get on the pH scale, the more basic your solution. The lower on the scale, the more acidic.

Houseplants need a soil that doesn’t fall below 5.5 or above 7.0. It’s that sweet spot in between. Going too basic or too acidic inhibits your houseplant’s nutrient absorption capabilities. When you give the plant fertilizer, it’s not getting the full extent of the nutrients promised. Your plant may make its own food much more slowly as a result.

Fred Zimmer

I'm a lover of plants, animals, photography, & people, not necessarily in that order. Currently, I'm focused on photographing indoor plants & chachkies. I write & rewrite articles about creating an environment where indoor plants can thrive. I'm good at listening to music but bad at shopping to muzak.

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