Different Types Of Fertilizer: The Ultimate Guide For Your Green Thumb

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When I moved into my new place, I planted flowers. They didn’t last long because the soil was dead. That’s when I started learning about different types of fertilizer, because, as I soon learned, fertilizers are essential to keeping plants healthy. And alive.

As I soon learned, there’s a lot more to fertilizer than I ever knew. There are different types of fertilizer for different types of plants. And, much like humans are affected by what we eat, so are plants.

If you feed your plant the wrong kind of nutrients (or the wrong amount of nutrients), you could end up with something unexpected.

Feed your plant the right types of nutrients (and in the right amount), and you’ll have a healthy garden, flower bed, and lawn all year round.

Because plants are organic, living things, they need food to live. And, just like humans, they need a well-balanced diet to grow and thrive. Part of that healthy diet includes water and sun. The rest of their diet comes from the soil.

You might think that soil is just dirt. And, you’re mostly right. But, did you ever think about what’s in the soil (other than worms)?

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There are six essential nutrients in your soil that help nourish your plants. Three of them, nitrogen, phosphorus, and potassium, are considered essential nutrients. Without these, your plants will starve.

Your plants also need other essential nutrients like calcium, magnesium, and sulfur, though in smaller amounts.

Feed Me

Soil, in conjunction with water and sunlight, feed your plants and help them grow. However, unlike many breakfast buffets, the nutrients in the soil are not an endless buffet.

Just like dinner at a fancy restaurant, you get only so much. The bread basket might be refillable, but your lobster is not. The same is true of soil. It feeds your plants as long as it can.

However, over time, continual use of the same land will deplete all the nutrients. And when that happens, your plants will go hungry.

That’s where fertilizer comes in.

You might think that only professional farmers need to fertilize their soil. They grow a lot of crops every year, so of course, they’re going to deplete the nutrients.

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However, the average home gardener or landscaper also needs to fertilize their soil. Just like a farmer, your regular use of your garden and even your grass will result in soil that, after a while, is tapped out and can no longer nourish your plants.

Adding different types of fertilizer to your soil helps replenish its nutrient content. It’s like taking another trip through the buffet line. Fertilizer helps to refill your plant’s plates so they can eat and grow healthy roots and produce more fruit, vegetables or flowers.

A Healthy Diet

Before we talk about different types of fertilizer, we need to talk about what’s in it.

As we stated above, plants need three essential elements to thrive, nitrogen, phosphorus, and potassium.

When we talk about these elements in relation to fertilizer, reach back to your high school chemistry class and try to remember the periodic table of elements. What are the symbols for nitrogen, phosphorus, and potassium?

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Give up?

It’s N, P, and K.

Yeah. The “K” for potassium got me, too.

When you buy different types of fertilizer, every label will tell you how much of each element is in the bag. It’s three numbers, and they are always the same. The first number is the amount of nitrogen, the second is phosphorus, and the third is the potassium.

On most bags, all you’ll get are the numbers, no symbols. But all types of fertilizer brands list them in the same order, N, P, then K. If you get a bag of fertilizer that says 5-5-5 on it, that means there are equal amounts of N, P, and K in the bag.

Specifically, it’s a ratio of N, P, and K per weight of the bag. So, if you buy a 100-pound bag of fertilizer that says 5-5-5 that means 5 percent of the fertilizer is N, 5 percent is P and so on.

Of course, if you buy a type of fertilizer with a different set of numbers, you’re getting a different ratio. A bag that says 7-5-4 would be 7 percent N, 5 percent P and 4 percent K.

The Different Types of Fertilizer

hand holding a soil

​Via Pixabay

There are two different types of fertilizer: organic and inorganic. While they are created differently, they are pretty much the same thing: nitrogen, phosphorus, and potassium. Before picking a type of fertilizer, know that each of them has advantages and disadvantages to consider.

What’s that smell?

Different kinds of rotten veggies in the pit types of fertilizer

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Organic fertilizers come from organic materials, like plants and animals. One organic fertilizer you might be familiar with is manure, but organic fertilizers can also come from fish as fish emulsion (ground up fish bones) or even from rocks (like calcium or phosphate rocks).

Many gardeners choose organic fertilizers because they want to avoid using chemicals in their gardening. However, if you use organic fertilizer, be aware that you may need to fertilize your soil more often than with a chemical fertilizer.

Unlike their chemical counterparts, organic fertilizers are considered slow-release fertilizers. Because they are not water soluble, the nutrients are released over a long period of time.

There’s nothing wrong with this. However, if your plant needs emergency nutrition, an organic fertilizer will not do the trick. You may have to consider using chemical fertilizer instead.

To help offset the slow release nature of organic fertilizers, you can incorporate compost into your soil. Using compost (like broken down grass clippings, eggshells, or even used coffee grounds), can give your plants some immediate nutrition while the organic fertilizer releases into the soil.

Some gardeners feel that using organic fertilizer (and compost) helps create a more workable soil, meaning it’s easier to use. Organic fertilizers tend to keep the soil softer, making it easier to turn over, dig, and plant in.

Inorganic but not fake

Pile of Fertilizer sacks in the farm

​Via Pixabay

Inorganic fertilizers come from non-organic sources. While this makes them mostly chemical, it doesn’t make them fake. Some of the nutrients in inorganic fertilizers are mined, while others are created in a lab. While some gardeners object to the use of chemicals, plants don’t know the difference.

Many inorganic fertilizers are water-soluble, meaning they are quickly and easily absorbed into the soil. If your garden needs an immediate feeding, inorganic fertilizer may be the way to go. Keep in mind, be cautious when applying the fertilizer. It is easy to overfeed a plant with inorganic fertilizers.

That said, some inorganic fertilizers are designed to be slow release like organic fertilizers. Here’s a quick tip to help you tell the difference. An inorganic fertilizer that is in a liquid form (or something that dissolves in water) is a quick release fertilizer. A dry (or pellet-like) fertilizer is usually slow-release.

Which One Works?

The one that makes your plants grow, of course!

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Different types of plants need different types of fertilizer. Not only will you use different types of fertilizer for different plants, the time of year and your specific climate influences the type of fertilizer you need to use.

It’s important to note that there’s no way to know what’s in your soil without testing it. While that may not be possible, there are other signs you can look for to tell you that you need to fertilize.

In general, if your grass is brown (or has brown patches), you probably need to fertilize your lawn. However, keep in mind that grubs could be the cause of your lawn problems.

If your garden or flower beds grow plants, but the blooms aren’t very big or seem to thin out with each passing year, it’s time to fertilize.

And, of course, if nothing grows, it may not be that you have a brown thumb. It may be time to feed your plants.

Tomato, carrot, and squash, oh my!

Group of vegetables on the table

​Via Pixabay

To produce the biggest and juiciest tomatoes (and everything else), you need to do two things. Keep the rabbits out, and fertilize properly.

Most soils have a sufficient amount of nutrients to grow vegetables. However, most vegetable plants require more nitrogen and phosphorus than the soil can provide. The best types of fertilizer to use would be something that is 10-10-10, 5-10-5, or 5-10-10.

Why so many choices?

While nitrogen is an essential plant nutrient, too much of it is not a good thing. When you overeat, you might feel gassy and bloated, maybe even a little tired. While a plant won’t feel bloated, too much nitrogen can make the plant sluggish and unable to produce fruits or flowers.

For example, if you’re growing something in the vegetable garden, you might find your plants produces a lot of vines but not enough flowers to result in vegetables. Or, in the case of root vegetables, you’ll get plenty of big leaves, but small roots (meaning smaller carrots).

In any event, a problem with your crop means a problem with the soil, likely too much nitrogen. While you probably can’t save that year’s crop, you can adjust the soil at the end of the growing season to correct it for the following year.

Fruit is better than vegetables

A bowl of different kinds of fruits


If you’re lucky enough to have a fruit tree, I’m jealous. Also, you should know that there are special fertilizer requirements for fruit trees.

Like vegetables, fruit trees need nitrogen to live. But, also like vegetables, they need just the right amount. Too much nitrogen in the soil will cause similar problems, as in lots of leaves but very little fruit.

The best ratio for fertilizing fruit trees is 1-1-1 or 1-2-1. If possible, try to get a fertilizer that’s half slow-release and half water soluble. This gives your trees an immediate feeding and also provides nutrients over the long term.

The flower bed

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There’s nothing like the beauty of a blooming flower bed. To keep yours in great shape, choose a fertilizer that’s either 10-10-10 or 5-10-5. Once again, too much nitrogen is the enemy here. Excessive nitrogen will create plants that have large green leaves, but little to no blooms.

Phosphorus encourages bloom growth. The right amount results in flowers that are bigger, more colorful and last a long time.

In most flower beds, slow-release fertilizer is sufficient. However, at times, you may find it useful to add a water-soluble fertilizer to help boost plant growth.

A perfect lawn

Green lawn

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No matter what kind of grass you have, fertilizing the lawn is a bit different than fertilizing the rest of your outdoor oasis. That’s because grass needs different types of fertilizer throughout the entire year.

For starters, you should plan on fertilizing your lawn four times during the year and by “year,” we mean the active growing season for grass in your climate. During the winter (or dormant season), you don’t need to fertilize your grass.

You’ll begin your fertilizing schedule some time in late spring (depending on when that is for you), then fertilize approximately every 6 to 8 weeks until the fall. So, if you started in May, you might also fertilize in June, September, and October.

For each feeding, you’ll use different types of fertilizer. For the first two feedings, use something that’s high in nitrogen, but (again), not too high. Excessive nitrogen will give you grass that’s very green but also grows very quickly.

The third feeding should be something that’s slow-release. By that point, your soil needs a boost, but not an immediate one. The last feeding needs to be high in phosphorus and potassium. This is the time to feed the roots and prepare them for hibernation, not encourage growth with nitrogen.

The Early Bird Schedule Isn’t Always Best

Watering the pink flower

​Via Pixabay

While some people like to eat dinner at 4:00, that’s not the right choice for everyone. Just like people, plants have internal clocks and schedules that they need to follow. To ensure the best plant growth, make sure you’re not only using the right type of fertilizer but also feeding your plants at the right time.

Safety first

Before we talk about when to feed your plants, let’s talk about doing it safely.

If you have a professional applying fertilizer for you, you can skip this section. However, if you’re a DIY gardener, there are a few safety tips to keep in mind.

In some towns, homeowners are not allowed to apply fertilizer to their outdoor plants at all. Some towns may allow it, but only if you get a permit first. If you’re not sure what the rules are where you live, check it out before you start. You wouldn’t want to get a ticket for feeding your plants.

Assuming you are allowed to apply fertilizer, remember these safety tips.

Wear gloves and goggles. While you’re at it, make sure you wear close-toed shoes (no sandals!), long pants and maybe even long sleeves. Better safe than sorry. On the off chance that fertilizer comes in contact with your skin or eyes, flush with clear water for 15 minutes.

Wait at least 48 hours before letting anyone (including pets) walk on the lawn (or wherever the fertilizer is applied). If possible, use a pet-friendly fertilizer.

Store the fertilizer where kids and pets can’t get into them.

If you used a granular fertilizer, sweep up any leftover grains and toss them in the yard or back in the bag. Make sure you wash off your shoes, too. Grain can get stuck in the treads, and you don’t want to track them into the house.

Let’s eat

So, we covered when to fertilize lawns, but we haven’t talked about everything else. Depending what you’re growing, you’ll have to plan out when you want to apply fertilizers.

For your vegetable garden, plan on fertilizing the soil once every 4 to 6 weeks during the growing season. In the early spring (before you plant anything), make sure to prep the soil with some fertilizer.

Fertilize fruit trees in the late fall or early winter depending on your climate. You want to get the fertilizer in the ground before the tree becomes dormant and can no longer absorb the nutrients.

The flower beds are a little trickier. When you fertilize depends on what you’re growing.

For annuals, apply fertilizer when you’re prepping the bed, then again about 6 to 8 weeks after you plant. If you’ve planted late bloomers (for fall), you may need to add a third application in late summer. For spring and summer bloomers, apply fertilizer as soon as you see new growth.

Add fertilizer when you prep the bed for perennials and again 6 to 8 weeks later.

Roses need fertilizer in May, June, and July. Do not fertilize them after July (depending on your climate). You could encourage new growth, and if there’s an early frost, you may harm the plant.

A Balanced, Healthy Diet

Fertilizing plants, grass, and even trees is more than throwing some food at it. Making sure you get the right types of fertilizer with the right balance of nutrients is essential to growing healthy plants.

However, not only do you have to get the right fertilizer, but you also have to feed your plants at the right time. Just like you may not want curry or meatloaf first thing in the morning, your plants may not want too much nitrogen late in the season.

A healthy garden, like a healthy person, starts with a healthy diet. It also includes a regular schedule of meals and lots of water and sunshine. So, check your soil, check your crops, and start feeding your soil today to have the healthiest outside possible.

Do you have any tips on fertilizing your plants? Share them with us in the comments below!

​Featured Image Source: Pixabay

Rachel Pelta

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