How To Fertilize An Indoor Herb Garden

Even Your Indoor Plants Need a Little Food

Assorted herbs on windowsill
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Once you have decided on the herbs to use for an indoor garden, you will need to choose the right fertilizer. Not all fertilizers are the same and, despite some of the advertising claims, all fertilizers can be overused enough to damage your indoor herbs.

What Types Of Fertilizers Can I Use Indoors?

There are many types of fertilizers that will work for an indoor herb garden. For indoor feeding, use a water soluble fertilizer or one that can be dissolved in water.

These can include: 

  • A packaged granular that you measure and dissolve in water before applying.
  • A fish emulsion that is concentrated and must be added to water before applying.

How Do I Apply Fertilizers?

No matter which type of fertilizer you choose, you will be applying it at one-quarter of the packaging's recommended rate. The standard fertilizer ratio is too concentrated for containers.

In an outdoor garden, the fertilizer naturally filters out into the soil surrounding the plant and the rest of the garden. This disperses the vital components and the plant takes as much fertilizer as it needs for healthy growth. For potted indoor herbs, everything inside the container is trapped inside the pot and there is nowhere for the fertilizer to go. This can lead to a build up and too much fertilizer can end up doing more harm than good for your plants.

To apply fertilizer in the most efficient manner, follow this procedure once a week:

  1. Mix the fertilizer at a strength of 1/4 of the manufacturer's recommendation.
  2. Water your herb plants thoroughly. 
  3. Apply the weak fertilizer solution. 

By watering the plant prior to fertilization, you will increase the plant's absorption rate. This is because the potting soil is already saturated and the roots are actively soaking up the water.

If you forget to fertilize for a week or more, do not over fertilize the next time to make up for the missed opportunity. Simply fertilize as if you didn't miss a week.

Monthly Maintenance When Fertilizing An Indoor Herb Gardens

Despite your best efforts, it is important to do a monthly flushing out of your indoor herb plants. The containers can trap harmful elements and salts inside the soil that would normally be filtered through the soil of an outdoor garden.

Also, the environment inside your home is not as friendly to natural cleansing processes such as fresh air circulation and rain. This can inhibit plant growth and counteract your fertilization efforts.

To keep your indoor plants healthy and happy, take the time once a month to flush the soil. It's very easy and is a chore you can do while working on other projects in your home.

  1. Simply place the herb plant in a sink and water it completely.
  2. Allow all of the excess water to drain out.
  3. Once it stops dripping, water it thoroughly once again.
  1. Allow it to drain completely in the sink and return it to its sunny spot.

This simple process will remove any salts that build up in the plant's soil and it is the perfect time for your weekly fertilizer.