How Deep does a Planter Box need to be for Herbs

When you are thinking of buying a planter box to grow herbs in, there are several things you will want to consider. First, you need to decide on the size and shape of your planter box.

Next, you will want to consider where your plants will be located and what type of planter box you would like to have. After that, it is just a matter of choosing the type of herb you would like to grow.

If you want your herb garden to be self-sustaining you need to get one with good drainage and enough room to allow for all the herbs you intend to grow to spread out evenly.

Choosing a Spot for your Planter Box

This will make it easier for you to keep them healthy, but you don’t want it to be too small. Your planter box also needs to have room to house a number of different types of herbs in it so you don’t have a shortage of containers to use. There are some things to look at when deciding which container to get and this article will help you get the right one for your needs.

Recommended Depth

The first and most important thing to consider is the type of herbs you intend to grow. Each type of herb has a slightly different growing medium and therefore requires a different-sized planter box for it to grow in. For example, a perennial herb such as basil requires a planter box that is 6 -8 inches deep, while an annual herb like sage requires a planter box that is 12 -15 inches deep.

Types of Planter Boxes

Some planters are made of ceramic, plastic, or even wood. Each material has advantages and disadvantages. Ceramic planter boxes are very inexpensive, but they can crack easily and need to be repainted often. Plastic or wood planter boxes may be more expensive, but they tend to hold their color longer than wood planter boxes. This tiered elevated garden below from Amazon is a great way to grow a large variety of herbs in a small area.

Soil Requirements

The next consideration is the type of soil your herbs need to grow in. Most of the common herbs and other plants require moist and loose soil for them to grow.

However, some herbs such as dill and oregano need their soil to be somewhat more firm and dense, so you need to take this into consideration before purchasing your planter box. Many people use gravel and peat moss to grow herbs, but many people swear by sand.

Most herb plants like to have some potting soil on them, but some herbs like to have their root ball completely enclosed in their planter. Either way you should be sure you are getting the correct potting soil for your plant to get the best results. 

Many people opt for an organic compost mix, because this is very beneficial and is rich in minerals that make it easier for the plants to thrive.

Mixing some sand with your potting soil is a great idea, because it is easier to work with and it keeps the soil from drying out. Be sure to buy soil that does not contain any chemicals so that the herbs do not become exposed to anything harmful.

Drainage System

Also, you will want to make sure that the drainage system in your planter can keep your herbs watered. When your planter is made of wood or a ceramic  it is easier to clean because you can just remove the soil and clean it on a regular basis.

However, you need to make sure that your drainage system is strong enough for your planter to keep your herbs watered without the water sitting on the ground. If you have a low drain, water can sit for days at a time, which is unhealthy for your herbs.

Air Circulation

The air circulation in a planter also plays an important part in how big should your herbs grow. Most planters allow for air circulation, but you should make sure that yours can keep the air circulating to keep your herbs healthy.

This is especially important during hot weather. If you live in a part of the world that experiences extremely hot weather, the temperature can get very high in your planter.


Once you know the size of your planter, you will be ready to plant your herbs and watch them grow. As you can see, it does not have to be very large to grow a lot of herbs. With the right amount of light and moisture, your herbs will bloom beautifully.


  • Vince S

    Hello, I'm Vince, and I bring over 25 years of dedicated experience in the world of herb gardening. From cultivating fragrant basil to nurturing hardy rosemary, my journey as a passionate herb enthusiast has allowed me to explore the wonders of these versatile plants. Through, I'm thrilled to share my knowledge, tips, and insights to help you embark on your own herb gardening adventures. Let's grow together!