Top 5 Most Common and Critical Fertilizer Mistakes

A plant experiencing chlorosis

Fertilizer is a huge factor to successfully cultivating a garden. Plants need a good amount of nutrients to survive as they use them for many basic functions. From growing their leaves to growing their roots, nutrients are the basis for plant growth. If you want to advance yourself as a grower, you’ll need to know a good amount about fertilizer to avoid these common fertilizer mistakes.

Why plants need fertilizer/nutrients

It is well known that plants need light and water to grow. They also need nutrients to perform certain tasks. Soil alone does not have all of the nutrients a plant needs to successfully thrive. Fertilizer has these nutrients which is why plants with fertilizer grow more than those without. There are a few primary nutrients, a few secondary nutrients and a few trace nutrients. They all matter, they just differ in how much of it you need.

The primary nutrients will be seen abbreviated as NPK. These are the most important nutrients for plants as they are consumed at a higher rate than the others. Secondary nutrients are definitely under-appreciated; they are important as they are used to do what NPK cannot. They may not be consumed by plants as much as NPK, but it is still important to have them in your soil. The same goes for the trace nutrients. They are consumed even less than secondary nutrients, but they still have a role to play in how a plant grows, survives and reproduces.

Primary Nutrients

  • Nitrogen- plants use this to make proteins in order to grow
  • Phosphorous- plants use this to help their seeds germinate and help the roots grow
  • Potassium- plants use this to produce flowers and fruit

Secondary Nutrients

  • Calcium- helps get other nutrients into the plant
  • Magnesium- helps with maintaining leaf health and chlorophyll

Trace Nutrient

  • Boron- used in conjunction with nitrogen to help the plant grow
  • Copper- useful in photosynthesis
  • Iron- helps move oxygen through roots faster
  • Zinc- helps produce chlorophyll

The Most Common Fertilizer Mistakes

  • Over fertilizing
  • Under fertilizing
  • Putting too much emphasis on NPK
  • Using a blanket approach
  • Wrong timing

How to identify and fix these common mistakes

     1. Over Fertilizing

Top 5 Most Common Fertilizer Mistakes

A plant leaf experiencing leaf burn from over-fertilization. Sourced via

If your plants are taking longer to mature than normal, is tall with weak stems, has yellow leaves, leaves that fall prematurely or reduced root growth, you may be over fertilizing.

The best way to fix over fertilization is to not do it in the first place. It is very difficult to notice the effects of over fertilization as they take a few days to show and by that point it is very hard to reverse. However, if you have over fertilized your plant, the best method to reduce the effects would be to give the plant as much water as the pot it is in will hold to bring the salt levels back down to normal. A good pot to use to both provide sufficient room to grow and good storage for soil is the Wally Eco Wall Planter.

     2. Under Fertilizing

Top 5 Most Common Fertilizer Mistakes

A plant experiencing chlorosis (left) next to a fully healthy leaf (right). Sources via

If your plant experiences chlorosis (loss of green coloring), stunted growth, purple/red leaves or dead plant tissue, you may be under fertilizing.

This is another difficult mistake to fix, fertilization is a very important part of growing so make sure you take your time researching what kind and how much fertilizer you need. If you notice the symptoms of under fertilization, you should retreat your soil. Restarting the treatment of the soil will allow your plant to thrive in the new conditions.

     3.  Over valuation of NPK

As stated before, NPK are the big guns when it comes to nutrients for plants. However, as is the case with most things in life, too much of a good thing can be a bad thing. If you have too much of NPK nutrients and too little of the others, your plants can experience symptoms of over and under fertilization.

Find good, well rounded fertilizer with more than just NPK in it. Plants need a well-balanced diet. They will utilize all of the nutrients that is available to them in the soil. Make sure your plant gets a good dosage of primary, secondary and trace nutrients. A good way to test your soil for the nutrient contents is with a soil test kit. One such as the Luster Leaf 1605 Digital Soil Test Kit is good for testing the NPK along with the pH of the soil. It is a fast tester that will get you your results fast so you can fix the problem as soon as possible.

     4.  Blanket approach

If you treat every plant and every soil type the same, you will not get the results you desire. Fertilization requirements vary depending on the plant, the location and the soil the plant is in. If you treat all your plants the exact same, you will likely experience either over or under fertilization symptoms as each plant has different needs.

Similar to the overvaluing of NPK nutrients, it is easily avoidable as long as you do your research. Find out which of your plants need which nutrients and how much. Also be sure to listen to your plant, if it gives you signals like yellow leaves, it is likely telling you there is a problem.  Check out our blog on yellow leaves and how to fix it to better understand the signals your plants are giving you.

     5.  Wrong timing

Depending on the type of plant you are growing, they may have dormant periods throughout the year. They also can vary in how much nutrients they need over certain periods. If you apply a nutrient after a plant needs it, its growth will be limited.

Again, do your research on when is best to fertilize your plants. You also should look into if your fertilizer is slow release. You don’t want to time up the fertilizing perfectly, just to have the fertilizer release late and miss the ideal time for fertilization. Paying attention to little details when growing and cultivating plants can go a long way to helping your plants grow as healthy and big as your heart desires.


Customer Reviews
5.0 Based on 581 Reviews
5 ★
4 ★
3 ★
2 ★
1 ★
Customer Photos
100reviewers would recommend this product Write a Review Ask a Question

Thank you for submitting a review!

Your input is very much appreciated. Share it with your friends so they can enjoy it too!

Filter Reviews:
I recommend this product

Working very well

We’ve been using our lights for 8 months now and really like their appearance and function. Great product.

I recommend this product

So far so good.

I’m writing this review for the 10% off. I’ve just received these lights, but after a week of use they seem to be working well. They are certainly more attractive than the average grow light and give a very nice ambiance. I’m not quite sure they are worth the cost, but I would probably still recommend these to someone who wants a visually pleasing grow light.

I recommend this product

Awesome Light

This light is beautiful and effective. My monstera is already growing faster!!

Sverre L.
I recommend this product

Beautiful + Great Instructions

It's a beautiful light and the entire kit is well thought-out – even the hardware is elegant! I also really appreciated the detailed booklet that covered not only install, but also a surprising amount of info on growing houseplants. I live in Alaska and have long used grow lights to keep my plants going through the winter. I recently purchased a bird of paradise and needed to up my growlight game. I could have rigged something up myself that looked nice for less money, but I was really curious about this company and wanted to check out their product, and I have no regrets. I haven't fully put the growlight to the test yet (we still have many hours of sun up here), but I've hung the light using Rousseau Plant Care's Curved Wood Wall Mount and I think together they increase the visual interest of my plant corner. Based on other reviews, I have no doubt that it will keep my bird of paradise happy through our dark season.

Soltech Solutions  Review

Related Articles

You might be interested in...

Sticky Traps from Amazon

8 Easy Ways To Get Rid Of Fungus Gnats Quickly


Pests are always a concern when it comes to the beauty and life of plants. Fungus gnats, although harmless to humans, are one pest that […]

Read More →
eduard militaru NgiE1A lIyY unsplash scaled 1

Bringing Your Plants in For Winter: A Step-By-Step Guide

Summer has officially passed and the cold temperatures are here to stay! As we switch to spending most of our time cozied up indoors, we […]

Read More →
best lights for growing plants indoors featured image 3 thegem blog default1

Best Growlights For Indoor Plants


Sometimes the toughest part about having houseplants is creating an environment for them to thrive. Worrying about your plants getting proper sun exposure can be […]

Read More →
Scroll to Top