Companion Planting Herbs in Containers
Are you wanting to grow herbs in your garden this year? While herbs can be grown in your raised bed or in-ground garden, perhaps you’d rather keep them close to your kitchen. Many of us choose to plant herbs in containers for that purpose.
When you plant herbs in containers near your home, they are only steps away from harvesting — ideal for a quick snip while cooking dinner. The good news is, for many herbs you can companion plant them together in containers. But for best results, though, there are a few things to keep in mind before you start planting.
The first question you’ll find yourself asking is how many plants can you fit in one pot all together. You may also be wondering if there are some combinations that pair well together and some that maybe need their own space.
Before you can answer those questions, though, you need to understand the difference between annual and perennial herbs. Knowing this will inform which herbs and how many will go in one container.
Annual vs. Perennial Herbs
Let’s first consider which herbs will last only for the season (annual) versus the ones that will last for years (perennial). This will help determine what herbs can be planted together.
Why does this matter? Some perennial herbs, like oregano, may start small, but they will eventually overtake a pot after a couple years of growth. This makes oregano an ideal companion plant with annual herbs the first year but one I would think twice about planting with another perennial herb.
Examples of annual herbs are basil, dill, and cilantro. You will plant and harvest them in the same year, and then they will die. You will re-plant them the following season, just like you do your vegetable garden.
Perennial herbs are a bit more complicated because whether an herb will survive your winter depends on your garden zone. Chives and mint, for example, are perennial down to zone 3. Oregano, sage, and thyme should survive to at least zone 5.
Any perennial herb that does not survive your winter can be treated like an annual. For example, marjoram does not overwinter in my zone 7 garden, so I can tuck it between other perennial herbs during the growing season and replant the following year.
Perennial herbs are the ones that need the most consideration when thinking about where to plant them. Some can be overly aggressive (like mint), some can spread over time (like oregano), and some grow quite large (like rosemary). Other perennial herbs grow slowly and/or don’t overtake containers and are generally excellent companion plants (like sage and thyme).
For more help on annual vs perennial herbs, click here.
The second consideration when planting herbs together in the same pot is the herbs’ water requirements. For the most part, herbs do not require as much water as the crops in your annual vegetable garden. In fact, many herbs (like lavender and rosemary) do better with less water and can suffer from overwatering.
However, herbs in the mint family (such as oregano, peppermint, marjoram, lemon balm, etc.) require more water than others. Planting them with each other can be beneficial because you can give them the same amounts of water. Keep in mind that many herbs in the mint family can be aggressive and aren’t the best companions, but others are.
For example, in this video below, I planted lemon balm and marjoram together (along with stevia), and they all did great throughout the season. I was just sure to water this particular pot more frequently than the others.
If you were to plant a herb like thyme (with less water requirements) with marjoram, for example, the water needs would be different enough between the two that you could struggle to make both happy at the same time.
How do you know which herbs need more water than others? This Herbs Quick Reference Chart makes it easy to find. (Download it here.) Any herb you may purchase as a transplant or start from seed, can be quickly looked up to see what plant family it belongs to. Generally, herbs in the same plant family require the same amount of water.
Pot Size for Companion Planting Herbs
Because herbs grow to different sizes, develop widely varying root systems, and may or may not survive your winter, choosing the best pot size for your companions can be daunting.
While over time, you may find your own preferences, here are mine:
- Choose a deep enough pot so that the mature size of the herb is of similar height.
- Plant 3-5 annual herbs in the same 12″ pot
- Perennial herbs in the mint family, mostly, get their own pot, a minimum of 12″ across.
- Aggressive perennial herbs (like oregano and peppermint) eventually will need repotted into a larger pot, 18-24″ or more.
- An 18″ pot can hold 2-3 non-invasive perennial (or annual) herbs
- As a general guideline, I will plant one non-aggressive herb for every 6″ of space across a pot.
Again, these are just general guidelines to get you started. Observe how different herbs grow in your garden and climate, and adjust as necessary.
Plant Combination Examples
Here are a few examples of companion planted herbs that have performed well for me in containers:
- Lemon Balm, Marjoram, Stevia (see video above)
- Thyme and Parsley (see video above)
- Oregano and Basil (with the oregano taking over in the second year)
- Sage and Chives
- Sage, Thyme, and Tarragon
Plant Spacing Requirements
On most plant tags attached to a transplant from the garden center, or on the back of the seed packets, you will see a section on plant spacing and how far apart you should plant the herbs from one another. Honestly, I don’t even look at that because planting herbs in containers is different from planting in the ground.
Instead, I look at the mature size the plant is expected to be. Often, this is listed on the plant tags as well, but sometimes I do have to search online. This gives me an idea how much room I should give each herb.
Even that, though, I take more as a recommendation. Herbs can flourish in close quarters with adequate water, and when they fill out a container, they are quite gorgeous! In addition, herbs benefit from pruning anyway, so if I need to keep them in check, I just prune when needed — also known as harvesting!
Before placing herbs in pots, consider their growth habits. If you know one herb likes to grow taller (like dill or rosemary), plant it toward the back of the container. If one likes to spill out more and spread low to the ground (like thyme), plant it toward the front so it won’t be shaded by the taller plant.
Truly, growing herbs is pretty simple and very rewarding in the long run. It can save you a lot of money so that you aren’t having to buy them at the store. If you want to learn more about how to grow herbs, you can listen to Episode 308 of The Beginner’s Garden Podcast. Click here if you want to learn more about how to preserve the herbs you already have growing.
And don’t forget to download this Herbs Quick Reference Cheat Sheet to help you get started!
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