Best Organic Fertilizer for herbs

natural fertilizer for herbs

For many of us, growing herbs is a passion. Using organic fertilizer for herbs helps us bring out the character and strength of flavor in our plants. Fertilizing herbs with a natural fertilizer is a powerful tool we can use to enhance the health-giving benefits of our herbs. 

In this article, we look at the best organic fertilizer for herbs, what herb plants need to grow, and explore whether homemade or store-bought organic fertilizer is better for your herb garden.

No matter what size garden you have, be it a balcony or a 10-acre plot, herbs are important for you. They make food taste better, smell amazing and have health benefits. Many types of herbs grow very well in pots. I have a huge garden and I still grow herbs in pots. Most herbs will take over the garden if you give them half a chance. 

What is the best organic fertilizer for herbs?

One that contains the essential macro and micro-nutrients your herbs need to grow. These are discussed below. Whether you make your own or purchase a ready-made one from the store depends on what you have access to.

Should you use organic or synthetic fertilizers for your herbs

There are many philosophical debates around the use of synthetic versus natural fertilizers. Synthetic fertilizers often provide quick wins – your plants look great very soon after adding fertilizers. They then provide a long-term crash. In other words, you will get lovely plants for a year or two, and then after that, you have to work hard to keep the plants healthy. The fertilizers just add nutrients, but nothing to go with it. Short-term gain, long-term pain.

Organic fertilizers tend to be formulated from substances that feed your soil – bone meal, feather meal, rock dust, and many other things which build your garden soil up. The idea is that we are growing plants in soil, not hydroponics – synthetic fertilizers often result in growing hydroponic plants in soil – the soil becomes so dead it does nothing but hold the roots. 

I try not to use inorganic fertilizer in my garden because I eat my herbs. Much like I do not enjoy synthetic colors in my food and drinks , I do not want synthetic compounds in my garden. Nature does its own thing, and we can work with it to our benefit.

spraying liquid fertilizer on herbs

Homemade or store-bought organic fertilizer

There are many natural fertilizers for herbs – many of these are made by fermenting fish waste, or seaweed, or a combination of these. Some are made from slow-release natural compounds such as bone meal and bird feather meal.

What type of fertilizer for herbs

Store-bought fertilizer comes as either granules or liquid. Slow-release or quick-release. The kind you choose depends on personal preference. 

Jobes organic all-purpose plant food is a great option if you want to buy an organic fertilizer online. 

Alternatively, look in the fertilizer section of your local gardening store. Look for an organic option and check for the following nutrients:

Main or Macro Nutrients

Nitrogen (N), Phosphate (P) Potassium (K). Optionally it won’t hurt if it also gives Magnesium (Mg), Calcium (Ca), and Sulphur (S).


Boron (B), Chlorine (CI), Copper (Cu), Iron (Fe), Manganese (Mn), Molybdenum (Mo), Zinc (Zn), and Nickel (Ni). There are other micronutrients, but normally these are needed in such small quantities that they will be contaminants in any fertilizer of biological origin hence don’t worry about them at this stage.

Follow the dosage instructions on the bottle when mixing and adding natural fertilizers for your herbs. Despite these fertilizers being organic, you can still burn your herbs by adding too much.

There is a common misconception that a natural fertilizer cannot hurt a plant. This is not the case – natural substances can be just as poisonous as synthetic substances – think of a death cap mushroom or a snakebite. 

It is always good to start low and go slow with fertilizers – you can always add more fertilizer, but you cannot remove fertilizer once it is in the potting soil and your plant goes yellow.

What do herbs need to grow and taste delicious?

Herbs are plants that produce secondary metabolites – molecules that have a protective function to the plant. These tend to be flavor compounds that make a plant unappealing or even poisonous to pests. 

If we look at the biochemical pathways a herb plant uses to synthesize these compounds, we can see what the plant will need to boost its growth and metabolism.

Secondary metabolites in plants give flavor

Secondary metabolites are generally complex molecules and are made using several enzymes in different parts of the cell. These enzymes are often compartmentalized in special areas using membranes. If the enzymes roamed around freely in the cell they would cause endless chaos. So we know that we need enzymes and healthy membranes.

Enzymes that make the flavor and the importance of metal ions

Enzymes are complex protein structures that hold a chemical in a specific way. This allows the active section of the enzyme to act on the chemical substrate and transform it into something else. 

Normally these active parts of the enzyme have a metal ion, such as iron, copper, or manganese, coordinated into the structure of the metalloprotein enzyme. The main structure of the enzyme is made of amino acids, which are made from nitrogen compounds. 

We can now see that herbs need nitrogen, a mix of metal ions, and something that makes stable membranes.

The importance of Phosphate for cell membranes

Cell membranes are composed primarily of lipid bilayers. Lipid bilayers require phosphate. The rest of the membrane can be synthesized by plants themselves – assuming they have the starting materials to make enzymes.

How this affects what must be in our natural fertilizer

Our natural fertilizer for herbs needs to supply

  • nitrogen for amino acids to make enzymes,
  • metal ions so the enzymes can work and
  • phosphates to make more membranes.

Then our organic herbs can fill the membranes with enzymes to make secondary metabolites to make our herbs smell great.

Hence for an organic fertilizer for herbs to be useful, it needs to have a source of nitrogen, and traces of useful metal ions and phosphate. There are a lot of options. When I started gardening I used to buy pre-made Organic Fertilizers for my Herbs. Now I make my own.

fertilizer for herbs in containers

Best organic fertilizer for herbs in pots

Herbs in containers need more fertilizer than herbs growing in soil in a garden. This is because there are limited nutrients in the soil in the pot. Once the herb absorbs these nutrients it needs more. 

Also the roots are more confined in a pot. So you can fertilize herbs in containers every 2 weeks with an organic fertilizer. A slow-release liquid fertilizer at half strength is best. Just be careful not to over-fertilize as the essential oils that give the herbs their flavour and aroma may be diminished with over use of fertilizer.   

How to make organic fertilizer for herbs

You can make your own organic fertilizer using a variety of options including

  • Manure tea bag
  • Egg shells
  • Banana peels
  • Coffee grounds
  • Fish emulsion
  • Seaweed soup

To find out more about how I mix my own liquid fertilizer for herbs read this article on the best homemade fertilizer for herbs.

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