Best soil for herbs in pots: what to buy and 3 easy mixes

What is the best soil for herbs in pots?

The best soil for herbs in pots is a bag labeled potting mix or potting soil. Both names mean the same thing. The same mix is the best soil for indoor herbs on a windowsill and for pots out on a porch.

Most bags hold peat moss or coconut coir, plus bark, perlite, a little lime, and a little plant food. There is usually no real soil in them at all.

Skip garden soil. In a pot, it packs down hard and stays wet. That leaves too little air for the roots, and wet, airless soil is how root rot starts. Garden soil can also bring in weed seeds, bugs, and disease.

Watch the name on the bag. Bags sold as “garden soil,” “raised bed soil,” or “topsoil” are made to mix into the ground. They are too heavy for pots, even when the bag says it is for herbs.

FoxFarm potting soil is one well-known bagged mix that works for herbs. For light, water, and the other basics, see our guide to growing herbs indoors.

The best soil mix for each kind of herb

Herbs fall into 2 groups. Some like the mix to dry out between waterings, so they need a mix that drains fast. Others like steady water, so they need one that stays evenly damp.

Herbs	Easy way	Make your own	Why
Rosemary, thyme, oregano, sage, lavender, marjoram, bay	2 parts potting mix to 1 part perlite, or a bag of cactus mix	2 parts peat, 1 part perlite, 1 part coarse sand[1]	Their roots rot if they sit wet
Basil, parsley, mint, cilantro, chives	Potting mix straight from the bag	1 part peat, 1 part vermiculite, 1 part compost[2]	They grow best in evenly damp mix
Seeds and cuttings	A bag of seed-starting mix	Half coir, half vermiculite or perlite	Light and clean, so tiny roots push through easily

A “part” is any scoop you like. Just use the same scoop for each one. Coir works in place of peat in either recipe.

Seedlings in a bark-rich potting mix with perlite. Image: Rob Bertholf

Rosemary, thyme, oregano, sage, and lavender: a fast-draining mix

For these herbs, mix 2 parts potting mix with 1 part perlite.^[3] The same goes for marjoram and bay. All of them like the mix to dry out between waterings.

Perlite is the white, crunchy stuff you see in potting mix. It is volcanic rock, heated until it pops like popcorn. It keeps air in the mix and lets water run through.

A bag of cactus or succulent mix works too. It is the same gritty mix we suggest for growing rosemary indoors.

You can use sand, but only coarse builder’s sand, never play sand. A handful does very little. A mix has to be almost half sand before it drains fast, so perlite is the easier fix.^[4]

Skip the layer of gravel in the bottom of the pot. It does not help the pot drain.^[4] Water just sits in the mix above the gravel.

A clay pot helps these herbs dry out between waterings. Our guide on how to pick the best pot for herbs compares clay and plastic.

Basil, parsley, mint, and cilantro: a mix that holds water

Plain bagged potting mix is right for these herbs. They like it evenly damp, never soggy and never bone dry.

To make your own, mix equal parts peat moss, vermiculite, and compost. Vermiculite looks like small gold-brown flakes. It soaks up water like a sponge.

If a pot of basil dries out in a day, move it to a bigger pot. More mix holds more water, so it stays damp longer.

How to choose the best potting soil for herbs

Pick a bag that feels light and fluffy when you squeeze it. Then check the label for 5 things.

• The name. It should say potting mix or potting soil. Leave garden soil, raised bed soil, and topsoil for the ground.
• What’s in it. Peat or coir, perlite, bark, and compost are all good signs. Skip bags that feel heavy or gritty, look dusty, or have hard clumps.
• Plant food. Many bags have slow-release plant food mixed in. The label tells you how long it lasts, often up to 6 months. That is fine for herbs you eat, but don’t add more food until that time is up. With a plain mix, start feeding lightly after 4 to 6 weeks. Herbs need very little, as our guide on how and when to feed herbs explains.
• Moisture control. Mixes sold as “moisture control,” or with water crystals or gel, stay wet longer. Skip them for rosemary, thyme, oregano, sage, and lavender.
• Organic. Organic mixes leave out man-made plant food and man-made wetting agents. A wetting agent helps dry peat soak up water. Both kinds grow good herbs, so pick the one you like.

What’s in potting mix, and what each part does

Each part of a potting mix does one of 3 jobs. It holds water, lets air in, or feeds the plant. Once you know which does which, you can fix any mix.

Part	What it does	Use more for
Peat moss	Holds lots of water. Very sour on its own, so bagged mixes add lime.	Leafy herbs, seeds
Coconut coir	Holds water like peat and soaks back up easily after drying out. Has almost no plant food.	Leafy herbs, seeds
Perlite	White volcanic grains. Keeps air in the mix and lets water drain. Never breaks down.	Rosemary, thyme, oregano, sage, lavender
Vermiculite	Gold flakes that soak up water and hold plant food. Flattens after a season or two.	Basil, parsley, seeds
Compost	Adds plant food and holds water. Use up to a third of the mix.	Leafy herbs
Coarse sand	Adds weight and a little drainage. Builder’s sand only.	Herbs that like to dry out

Compost from your own bin works well in any of these mixes. Our guide shows how to make compost at home.

When to repot herbs into fresh potting mix

Repot herbs that live for years, such as rosemary, thyme, sage, oregano, mint, and chives, about once a year.^[4] Use fresh mix, and do it in spring, when they start to grow again.

Old mix breaks down into smaller bits over time. It packs down, holds less air, and drains worse.

Signs it is time to repot:

• Roots circle the pot or poke out of the drainage hole.
• The mix dries out very fast, or water runs straight through.
• Growth stalls, even though you feed it.

Go up just 1 to 2 inches in pot width. A pot that is far too big stays wet for too long.

Reusing old mix. Mix from a healthy plant can be used again. Break it up, pull out the old roots, and mix it half and half with fresh mix.^[5] If you are not sure it is clean, sterilize old potting mix first. Throw out mix from a plant that died of root rot or another disease.

Questions & answers

Can I use regular potting soil for herbs?

Yes. Regular all-purpose potting mix is the right soil for most herbs. For rosemary, thyme, oregano, sage, and lavender, stir in 1 part perlite for every 2 parts mix.

Can I use Miracle-Gro potting mix for herbs?

Yes, if the bag says potting mix. Most kinds have plant food in them, so don’t feed until the time on the bag is up. Skip the Moisture Control kind for rosemary and other herbs that like to dry out. Miracle-Gro Garden Soil is made for the ground, so keep it out of pots.

Can I use garden soil for herbs in pots?

No. In a pot, garden soil packs down, stays wet, and chokes the roots. It can also bring in weeds and bugs. Keep it for garden beds, and buy potting mix for pots.

Can you use cactus soil for herbs?

Yes, for rosemary, thyme, oregano, sage, and lavender, which like to dry out. It dries too fast for basil, mint, parsley, and cilantro.

Do herbs like acidic soil?

Only slightly. Most herbs grow best at pH 6.0 to 7.5, where 7 is neutral and lower numbers are more sour. Fresh bagged potting mix starts near 6.2, so you rarely need to change it. To check an older pot, see our guide on how to test soil pH.

What is the best soil for herbs in a garden bed or raised bed?

Any good garden soil works if it drains well. Mix in compost before you plant. If the spot stays wet after rain, grow your herbs in a raised bed instead.

Feature image: John Tann

References

1. Clemson Cooperative Extension, Indoor Plants: Soil Mixes. https://hgic.clemson.edu/factsheet/indoor-plants-soil-mixes/ ↩︎

2. Penn State Extension, Potting Media and Plant Propagation. https://extension.psu.edu/potting-media-and-plant-propagation ↩︎

3. University of Maryland Extension, Growing Herbs in Containers and Indoors. https://extension.umd.edu/resource/growing-herbs-containers-and-indoors ↩︎

4. NC State Extension, Extension Gardener Handbook: Plants Grown in Containers. https://content.ces.ncsu.edu/extension-gardener-handbook/18-plants-grown-in-containers ↩︎ ↩︎ ↩︎

5. University of Maryland Extension, Growing Media (Potting Soil) for Containers. https://extension.umd.edu/resource/growing-media-potting-soil-containers ↩︎