Does Basil Need Fertilizer? (Everything You Need To Know)

Basil is a popular herb to grow.  This herb adds flavor to many dishes.  Growing basil is easy.  However, you may be wondering, “Does basil need fertilizer?” 

Fertilizers have gotten more expensive and may seem like an unnecessary expense.  This guide will discuss whether you need to fertilize your basil or can grow it without fertilizer. 

Does Basil Need Fertilizer?

Sometimes basil can grow without fertilizer.  If basil is grown outdoors in fertile soil, it can grow without fertilizer.  However, it will not grow as well as when it is fertilized.  You will need to fertilize the basil in containers or hydroponically to get a healthy crop.

Can Basil Grow Without Fertilizer? 

Basil that is grown outdoors in fertile soil will grow without fertilizer.  Usually, you will get a much larger plant if you fertilize the basil in the ground.  Basil grown in pots, whether indoors or out, will need fertilizer since the plant quickly uses the nutrients in the pot. Hydroponically grown basil needs fertilizer to grow, or it will die. 

What Nutrients Does Basil Need to Grow? 

All plants require large amounts of nitrogen, phosphorus, carbon, oxygen, hydrogen, and potassium to grow.  Plants also need other nutrients in small quantities.  These include calcium, magnesium, and sulfur.  Finally, plants need boron, chlorine, copper, iron, manganese, molybdenum, and zinc in minute quantities.  Without any one of these elements, the basil cannot grow and complete its lifecycle. 

Too Much Of A Nutrient Kills 

Too much of a specific nutrient can make a plant sick and can even kill it.  Do not exceed the recommended nutrient dose, or you may kill your plants. 

What Fertilizer Does Basil Need? 

Choosing a fertilizer can be a bit complicated.  Basil will not have as much essential oil in the leaves if you over-fertilize it. So you need to put just the right amount of fertilizer but not too much. 

The best basil fertilizer has nutrients not already in the soil.  The best way to determine what fertilizer you need to apply to your basil is to do a soil test.  You take a sample of the soil in which you will be planting the basil and mail it to the soil lab for your state or province.  Tell them you want to grow basil.  The results will include what is already in the soil and what you need to add to grow your basil. 

Without a soil test, here are some general guidelines for fertilizing your basil. 

In the Ground 

Before planting your basil, work a 5-10-5 fertilizer formulated for herbs into the top six inches of soil.  After six weeks, if the basil is not growing well and is pale green, fertilize with calcium nitrate.  Follow the directions on the fertilizer package.   

Dr. Earth Organic 5 Tomato, Vegetable & Herb Fertilizer is a good organic fertilizer.  You can use the same fertilizer to add calcium nitrate if you need it. 

A good synthetic fertilizer is Espoma GF51056 Garden Food Fertilizer 5-10-5

A good synthetic source of calcium nitrate is Bloom City Professional Grade Ultra Pure Cal-Mag Growing Fertilizer

In Containers 

When basil is in a container indoors, you will need to fertilize it with a half-strength water-soluble fertilizer every four to six weeks.  For outdoor containers, fertilize every three to four weeks.  

A good organic fertilizer is Burpee Organic Tomato and Vegetable Water Soluble Plant Food 6-2-3.  A synthetic option is Miracle-Gro Water Soluble Plant Food Vegetables & Herbs

Hydroponic  

Basil can be grown hydroponically but requires a fertilizer formulated for hydroponics.  Most hydroponic fertilizers are synthetic because they have to provide everything the plant needs.  A good synthetic fertilizer is Miracle-Gro AeroGarden Liquid Plant Fertilizer for Use in AeroGarden Hydroponic Indoor Garden.  

Homemade Fertilizer for Basil 

Basil will grow best with commercial fertilizer. Homemade fertilizer may not contain all the required nutrients. Basil grown hydroponically needs special fertilizer so that homemade fertilizers won’t work. Here are some things people have used as homemade fertilizer and how well they work. 

Homemade Fertilizer for Basil

Coffee Grounds 

Coffee grounds have nutrients that most plants need. However, coffee grounds are very acidic, and basil grows best in alkaline soils. Therefore, putting coffee grounds around your basil may make the soil too acidic for the basil to grow well. 

Banana fertilizer 

Banana peels add potassium to the soil. Therefore, they should be buried in the top layer of dirt to decompose and make that potassium available. Indoors, the banana peels will have a bad smell while decomposing. Outdoors, adding potassium without nitrogen and phosphorus can cause an imbalance of nutrients in the basil and keep it from growing well. 

Eggshells 

Eggshells are a good source of calcium. First, you will need to wash out the eggshells and let them dry. Crushed eggshells have to decompose before they release their calcium, which can take up to a year. So instead, grind the eggshells into a powder and spread it around the basil. 

Compost 

Compost makes a good addition to the soil. Mixing an inch of compost into the top three inches of soil will provide nutrients and help aerate the soil. Make sure the compost is fully composted so it will not burn your plants. 

When and How Often Do We Need to Fertilize Basil? 

If you are growing basil in the ground, fertilize when you plant your basil seeds or transplants. Check your basil six weeks after planting. If it is pale green and isn’t growing well, fertilize again. 

If your basil is in a container indoors, fertilize every four to six weeks during the growing season. Basil in outdoor containers needs fertilizer every three to four weeks.  

If you grow basil hydroponically, you will add the fertilizer to the water solution your plants are growing in. How much fertilizer you add and how often you add it will depend on the hydroponic fertilizer you buy. Follow the label directions for best results. 

How to Fertilize Basil Properly? 

Basil is fertilized differently depending on whether the basil is in the ground, in a container, or grown hydroponically. 

How do you fertilize indoor potted basil? 

Use water-soluble fertilizer formulated for herbs. Mix the fertilizer at half the recommended strength. Every two weeks, water the basil with fertilizer instead of plain water. 

How do you fertilize outdoor potted basil? 

Outdoor potted basil is fertilized the same way indoor potted basil is fertilized. See above for the instructions. 

How do you fertilize basil in the ground? 

The same day you plant your basil, mix dry fertilizer in the top three inches of dirt. Then, plant your basil normally and water the plants or seeds. Water is necessary to release the nutrients in the fertilizer so the plant can use them. 

Six weeks after planting the basil, check the leaves and growth. If the leaves are pale green and the plant is not growing well, you need to fertilize again. This time, put the fertilizer six inches from the plants. Water the plants and the fertilizer, so the nutrients are released for the plants. 

How do you fertilize basil grown hydroponically? 

Basil grown hydroponically sits in the water with fertilizer in it. Use a fertilizer formulated for growing basil hydroponically and follow the instructions on the label, as the amount of fertilizer you use depends on your system. 

Common Problems When Fertilizing Basil 

You can have several problems when fertilizing your basil. These are the most common ones. 

Too much fertilizer per application 

If you use too much fertilizer, you will burn the plant and can even kill it. Therefore, always follow the instructions on the label when fertilizing. 

Fertilizing too often 

Fertilizing too often can build up a residue that can burn or kill your basil. In addition, too much fertilizer will reduce the amount of essential oil in the leaves, so they will not taste as good. 

Using the wrong fertilizer 

If you use a fertilizer that is not formulated for basil or herbs in general, it can contain the wrong amounts of the nutrients basil needs to grow. For example, too much nitrogen makes the plant grow so rapidly that it doesn’t have enough essential oil in the leaves. Too little or too much boron will kill basil. 

Not fertilizing 

Not fertilizing basil

While your basil will grow in the ground without fertilizer, it may or may not grow. If you do not fertilize your potted plants, whether indoors or outdoors, they will not grow for long. The nutrients are quickly used up, and unless they are replaced by fertilizer, the plant will stop growing and die. When growing basil hydroponically, you must use the required fertilizer levels because that is the only way the basil gets the needed nutrients.

In conclusion, while basil will grow without fertilizer in the ground, it may not grow as well as fertilized basil. If the basil is in a container or growing hydroponically, it will starve and die without fertilizer. 

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Stephanie Suesan Smith

Stephanie Suesan Smith has a Ph.D. in psychology that she mainly uses to train her dog. She has been a freelance writer since 1991. She has been writing for the web since 2010. Dr. Smith has been a master gardener since 2001 and writes extensively on gardening. She has advanced training in vegetables and entomology but learned to garden from her father.

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