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How to Fertilize Basil Plants for Your Best Harvest Ever

Watering and pruning your basil will help it grow significantly. However, if you want the best harvest ever, all you need is a fertilizer. Each plant requires a different type and amount of fertilizer. Continue reading to find out everything you need to know about basil fertilization.

Ways of fertilizing basil plants.

Hi there, my fellow basil fan. If you’re reading this article, you’re either planting your own basil for the first time, or you weren’t happy with the last harvest you had from your basil plant. Perhaps you slacked on watering and pruning, or you forgot about fertilizer. Either way, I’m here to help! We’ll be reviewing all things fertilizer, so you’re in the right place. Hooray!

When it comes to fertilizing basil plants, less is actually more, as backwards as that may sound. I know, my instinct too was that a small herb plant like basil would need all the help it can get, but basil actually does best with just a small amount of fertilizer. 

You see, too much fertilizer can compromise the quality and the taste of your basil. I don’t know about you, but when I need to add basil to my pizza or pasta, or put it in the blender for some fresh pesto, the last thing I want is poor tasting basil! It can throw off the whole flavor profile. 

Keep reading to learn more about everything you need to know, from why basil doesn’t need much fertilizer, to what kinds of fertilizers are available, to the proper use and storage of fertilizer. I am hopeful you’ll have all the information you need to achieve your best basil harvest ever!

What is the purpose of fertilizer?

A hand with gloves holding a chemical fertilizer.

Now, before I begin, I think it’s helpful to quickly review why plants need fertilizer in the first place, and what its purpose is. If you’re a gardening pro and you just need more information on fertilizing basil specifically, feel free to skip this section. 

Commonly, fertilizer is used on plants and herbs to help feed them to maximize growth. It acts as a sort of supplement or vitamin to provide extra nutrition to the plant. 

Fertilizer is especially helpful when the soil is not rich in nutrients, or when you are growing a plant that may become deficient in a certain element (such as nitrogen, phosphorus, or potassium). If you think your soil may be deficient, you can conduct an at-home soil test to assess whether a little extra fertilizer may help to balance it all out. 

How often should you fertilize your basil plant?

A basil sprout with fertilizer on ground.

If your soil is properly balanced, then you’ll only need to use fertilizer sparingly.

You’ll want to use (sparingly) 10-10-10 NPK fertilizer for your basil plants. NPK stands for nitrogen / phosphorus / potassium. If you remember the table of elements from your high school chemistry class, N, P, and K are these chemicals’ letter symbols. 

When a fertilizer is 10-10-10, it means that it has 10% each of nitrogen, phosphorus, and potassium. This is generally considered to be a standard fertilizer ratio. 

Like I said above, I suggest testing your soil before buying fertilizer to see if your soil needs an extra boost. If you have rich soil, you should only need the fertilizer a few times throughout the season. So don’t go running to Costco or anything for a giant bag of fertilizer––you really won’t need all that much! 

Liquid versus solid fertilizer for basil

A woman spraying liquid fertilizer on basil in pot.

Once you’ve found a 10-10-10 fertilizer, you’ll need to decide whether to go with a liquid or a solid fertilizer. The most common household fertilizer is liquid, and that’s what I would recommend if you’re just starting out in gardening. 

Liquid fertilizer is really easy to use; you’ll just need to mix it with the right amount of water. The directions on the back of the bottle will tell you what that mixture ratio is. You can also use a sprayer to spray the fertilizer for an even better distribution. Just be sure to apply the liquid mixture directly to the soil under the leaves; don’t spray it over the top of the plants.

Solid (or granular) fertilizer, on the other hand, is not absorbed as quickly by plants as liquid fertilizer. This is convenient because it means you don’t need to apply the fertilizer as frequently. If you go with a granular fertilizer, you’ll need to sprinkle it directly on the soil under the leaves. Then, take a fork and dig the fertilizer down into the soil and water it generously. 

You want to be sure you water the solid fertilizer into the plant so that it’s properly absorbed. It can feel a little more like a guessing game with granular fertilizer, because you’re not exactly sure whether you’ve watered the soil enough for the fertilizer to be seeped and evenly distributed. 

This is why I recommend that beginners start with liquid fertilizer. The instructions on the back take all the guessing out of it! 

How to properly apply fertilizer 

A hand in yellow gloves planting basil plants.

I kind of like to look at the process of caring for plants the same way I look at the process of getting my hair done. There’s the wash and conditioner, then the cut, then the styling. Fertilizer comes at the end, like styling.

It should happen after you’ve done everything else (watered the plant, pruned and cut). I guess if you’re going to be watering the plant with the fertilizer, you could just give it a quick spritz before you prune and cut. It’s up to you. You just want to be sure that you put the fertilizer on a well pruned basil plant to optimize its effectiveness. 

It will depend on whether you’ve chosen a liquid or solid fertilizer, which I explained above. Either way, don’t drench the basil plant in fertilizer––especially if you live in a hot and humid environment. This is not baptism by immersion. The basil will already be thriving on its own. You’re applying the fertilizer just to give it a little oomph. 

Fertilizer will not kill your basil plant.

A healthy basil plants in the garden.

As long as you properly place the fertilizer in the soil, water the plant appropriately, and do not get any fertilizer on the basil leaves, you will be just fine. If you get fertilizer on the leaves, wipe it off immediately to prevent the leaves from being burned by the NPK chemical mixture. 

So I guess all that is to say, fertilizer may burn your basil leaves if it’s left there too long, but it will not kill your basil plant. It just may not grow and reach its maximum harvest if you use too much of it. Have I gotten that point into your head yet?! I hope so!

Natural fertilizer options

A mixture of natural fertilizer in a box.

In addition to liquid versus solid fertilizers, there are more natural and organic kinds of fertilizer options that are usable with basil. I know many gardeners aim to prioritize organic nutrients and techniques in their harvests. 

Organic fertilizer, also known as 4-4-4 fertilizer, has the same NPK ratio as 10-10-10 (the same amounts of N, P, and K) fertilizer, it’s just less potent. This is why it’s considered organic, because it’s a more diluted and natural solution. Organic fertilizers contain tiny microorganisms that help to improve the soil makeup over time. This means the soil will be better positioned to retain water and nutrients. 

However, this is a much longer process than say a liquid fertilizer because it is, well, more natural. I know it’s frustrating if organic gardening is important to you, but it’s just the name of the game. So, if your heart’s set on natural and organic gardening, be sure to take this into consideration.   

FAQs

Here are some answers I’ve put together based on some other related questions I got about fertilizer for basil plants. I hope this is insightful for you!

Is proper fertilization enough to maximize my basil plant’s harvest?

In addition to properly fertilizing your soil and basil plants, there are a handful of other techniques that can help you to maximize your harvest. 

First, make sure you have enough sunlight. I know this seems like a no-brainer, but basil does best in direct sunlight, for 8 hours per day. So, if you have the choice between a spot with some shade and a super sunny spot, pick the sunny one. 

You also want to make sure you are cutting and pruning your basil regularly. Consistent pruning encourages new growth, which means a greater harvest. Always leave at least half of each stem’s length intact on the plant. If you cut too close to the base, then you will stunt its growth. Cut above leaf pairs when you are cutting the stem. This will have an exponential effect, as the stem will grow back twofold. 

A freshly harvested basil leaves.

In addition to sunlight and consistent pruning, wait to plant your basil until your soil reaches 70ºF in temperature. If you plant it too early, it will not get the momentum it needs to grow. 

You will also stunt the momentum if you do the first cut too early. Wait until the basil plant reaches 6 to 8 inches in height before the first cut. Otherwise the plant will not have the energy it needs to bloom to its full potential. 

Do banana or coffee fertilizer methods work?

As you’ve been searching for tips and tricks to maximize your basil harvest through proper fertilization, you’ve probably come across claims that homemade banana or coffee bean fertilizers are effective. This is not true. 

Bananas contain potassium, yes, but plants will only absorb nutrients as they need them. The same principle applies to coffee beans. Coffee beans are natural and organic, but they may harm the plant more than help it. As coffee beans decompose in the soil, they’ll absorb the nitrogen and deprive the basil of the food it needs. 

Does it matter how I store my fertilizer?

A hand holding fertilizer from the sack.

Make sure to store your fertilizer in a cool dry place. I thought my garage was a “cool dry place” until I realized how hot it gets in there in the summertime. I’m not saying you need to add ventilation and AC to your garage, but just try to be smart about where you put it. And if you have little kids at home, please be sure to store the fertilizer high off the floor if possible. The last thing we need is them getting into it!

Keep your fertilizer in its original bag or packaging. This will ensure it stays with its original ingredient list and instructions. I know it may be tempting to transfer it to another container, but you don’t want to forget what the product is specifically, or what all its ratios and directions are. 

If you need to store it in something, just put the whole bag (or bottle) of fertilizer in a plastic bin or even a large garbage bin. I remember my grandfather used to do this with the dog food, to ensure his dog wouldn’t be tempted to have a midnight snack. 

Finally, keep it away from any possible water or moisture. What I mean is, don’t leave it by the hose or a sink. We want to keep moisture out of the fertilizer bag (or bottle). If you’re up for it, this could be a great excuse to reorganize the garage or even build out a specific “gardening supplies” area of your garage or shed. I’m a sucker for any excuse to re-organize any part of my household!

Will fertilizer burn my skin?

Because fertilizers contain chemicals, there is always the risk of irritation if fertilizer is mishandled. Touching the fertilizer may irritate your skin, but the greatest risk is ingesting or inhaling it. If this happens, you’ll probably want to call poison control immediately. Be careful not to rub your eyes or face if you’ve been working with fertilizer without gloves on.

As the old adage says, it’s better to be safe than sorry. Throw on a pair of gloves, store the fertilizer in a secure, safe, cool and dry place, and wash your hands when you’re all done. You don’t want an enjoyable day in the garden to be brought to a disastrous halt because of something that could have been so easily avoided!

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