Which Soil is Best For Rosemary Growing in Pots?

Last Updated on November 5, 2022 by Stephanie

While overwatering is the main cause of rosemary plants in pots dying, choosing the right pot soil is just as crucial as a proper watering schedule. This is because if the rosemarys roots are placed in a potting soil that holds plenty of moisture, it roots will rot, even if you water your rosemary in the right quantity…

The soil used for potting rosemary is quick to drain, doesnt retain a lot of moisture, and is relatively fertile to thrive and give the most fragrant aroma. Try to use two-thirds compost and one-third horticultural sand for the most potent potting mix you can get for rosemary.

Read on to find out how to make the most effective potting mix, and why you should not use peat moss, and how to avoid the most common mistakes when planting rosemary…

Criteria for Good Potting Soil for Rosemary Plants

  • Porous, well-drained soil that doesnt hold water for long.
  • Aerated soil structure that allows for effective respiration of the roots (rosemary is not a fan of soil that is compacted).
  • Low fertility to medium fertile soil.
  • The soil of rosemary must be rich in organic material (similar as the sandy and grity soils in its native habitat).

The herb rosemary originated in the Mediterranean region of Southern Europe where it is naturally found on the hillsides within Spain, Portugal and France.

In its habitat on the hillsides, the rosemary flourishes on sandy and grippy soils that are poor in nutrients and rapidly drain, retaining very little water.

Hillsides are naturally able to drain well and the aerated, gritty porous soils guarantee that any excess moisture doesnt remain in the ground around roots because it can cause root decay which is among the most frequent issues that plagues rosemary growers.

Soils that hold a lot of moisture, such as amended compost that has clay soils or wetting agents increase the risk of fungal diseases affecting the rosemary plant, which could change the leaves to either black, brown, or yellow and cause it to die back.

(Read my article on the best way to bring back the dead rosemary plant).

If you plant rosemary in soil that is high in nutrients, such as compost, loam soil with fertilizers added or soil that has been altered by manure (which is extremely high in nitrogen) Then these soil conditions are not compatible with the gritty, low fertility sandy soil conditions to which the rosemary has specifically developed.

The richness of the soil in nutrients makes rosemary in a droopy manner, and the addition of nitrogen in the soil decreases the amount of essential oils within the leaves that are the reason for rosemarys distinct scent and taste. So if you plant rosemary in fertile soil, it wont smell or taste the same as many blooms.

The rosemary plant actually thrives in containers and pots as containers have favorable drainage conditions that mimic the well-draining conditions that are found naturally on hillsides.

The most important thing to keep the health of your potted rosemary garden is to mimic its well-draining Mediterranean soil condition…

flowering rosemary

How to Create the Perfect Potting Soil for Rosemary

While you dont require an Mediterranean climate to cultivate rosemary, it is possible to create the conditions for a soil.

To make the most suitable soil for rosemary to grow in pots, it is essential to mimic the sandy, grippy, moderate to poor fertility soil conditions found in the natural Mediterranean environment.

This is accomplished by amending the multipurpose compost by adding coarse sand for horticulture or grit.

The horticultural sand and grit replicates the inorganic component of the soil that is natural to rosemary. It is extremely stony and sandy providing excellent drainage as well as an open structure that allows for oxygen to circulate in the soil, which is essential to allow root respiration as well as stopping any soil compaction that could slow drainage.

To replicate the rosemarys Mediterranean soil Mix at minimum 30% horticultural sand or grit and 70 percent compost.

A lot of sand or grit is better than not enough, as the sand greatly reduces the possibility of root rot, which is the most frequent cause for the dying rosemary plant.

If you reside in a region with higher rain (such such as Pacific North West or Northern Europe) then I suggest including a larger amount of either sand or gravel to the soil.

The rosemary plant has been specifically designed to withstand drought environments and soils that are dry, therefore it is crucial to stress how essential rosemary needs the soil to be draining.

The addition of grit or sand to the mix can help combat the effects of climates with high rainfall and the rosemary will grow quickly once it has started developing in its ideal well-draining environment.

I have spoken with commercial lavender and rosemary Mediterranean herb farmers from Washington as well as Oregon who suggest amending their potting soils by adding as much as 50 percent horticultural sand, or the grit mixture to 50% multi-purpose compost in order to achieve the best drainage balance for rosemary to thrive in spite of a wet climate and conditions.

Sand and grit contribute to the fact helping to establish the ideal soil fertility that is suitable for rosemary.

Its as surprising as it might be, rosemary thrives in soils that have lower fertility and produce the most delicious flavor and aroma from its leaves, as well as the highest number of flowers.

Sand and grit dont provide any nutrients to soil, which aids in balancing the fertility of the compost you use for your potting soil, allowing it to replicate the same level of soil fertility as the Mediterranean range, ensuring that your rosemary is bursting with flavor and aroma.

The rosemary is able to get every nutrient they need from the grit, compost mix.

Beware of this error!

It is crucial to remember that you cant replace horticultural sand by regular beach sand for your rosemary mixing.

The sand used for horticulture is coarser and has a bigger particle size than ordinary beach sand, which are much finer.

The larger sized horticulral sands let more air into the soil, allowing the water to drain more efficiently.

Sand particles from beaches can be tiny and can create soil mixes that drain too slowly and eliminate oxygen through less porous structures.

The horticultural sand, grit, or perlite are usually sold at a reasonable price at garden centers or on Amazon.

(Read my article on selecting the most suitable containers for the rosemary).

Potting Soil pH for Rosemary

The native habitat of rosemary is that have calcareous soils, which tend to be alkaline in pH. The most commonly used acidity range of rosemary can be the pH range of 6-7.5 (which is slightly acidic, neutral and a little alkaline) However, some varieties of rosemary can tolerate pH 4.3-8.3.

The majority of commercially available potting soils as well as compost are within the optimal pH 6-7.5 range, with only soils labeled as ericaceous must be avoided because it means that it designed specifically for plants like camellias that require more acidity levels.

There is no need to amend the soil using lime or any other substance which raises pH to an alkaline. While it is unlikely to harm the rosemary, it could cause harm if you apply excessive.

(Read my article on on how you can take care of the rosemary inside pots).

Do not amend Rosemary Potting Soil with Peat Moss

The reason you should avoid peat moss is that it is a hard baker in full sunshine (rosemary needs full sunlight) and turns hydrophobic after it dries , which means that it blocks water from the surface of the potting soil. This causes water to flow across the soil, and then down the sides of the pot, without getting into the roots.

The rosemary is a drought-resistant plant, however if water is being sucked away from on the top of soil, the roots are unable to absorb any moisture, and the rosemary will die back.

Always opt for a peat-free compost, or pot soil when making your rosemary potting mix that should be clearly labeled on the package.

In addition to the peat content, it is also not recommended to plant rosemary in any compost that contains added fertilizers or wetting agents because both are contrary to rosemarys preferred soil conditions.

A normal multi-purpose compost that has been modified with grit or sand is the best soil mix for rosemary.

(It is vital to know when you should water your potted rosemary in order to complement the drainage of the soil, to ensure the ideal balance of the amount of moisture in potted rosemary, so check out my article on on how you can water your rosemary to learn the best methods of watering).

Key Takeaways:

  • Rosemary likes dry, poor sandy potting soil that has low fertility. Make the most fertile soil for potting rosemary using two thirds of compost and one third horticultural sand that recreates the ideal soil conditions of the native rosemary Mediterranean habitat.
  • Do not plant rosemary in potting soils that contain fertilizers added to them or in soils that hold excessive moisture, as this can cause root decay.
  • The sand used in the production of horticulture is larger in particle size, which helps replicate the porous aerated soil to which the rosemary has adapting and encourages drainage, and lowers the risk for root rot.
  • The rose can thrive in pH neutral, acidic as well as alkaline soils. Mixes of compost and sand dont require to be amended with lime since rosemary is able to thrive in the typical pH range of soil.
Stephanie

Stephanie

Went from an inexperienced gardener to a half-decent one over 10+ years. I cover anything from general indoor plant guides and lawn care, to succulents and flowers. Super happy to share my tips and tricks with you :)