Peppermint: Cultivation in Pots and Garden

Today, we get to know the peppermint, a well-known aromatic plant. It is a plant appreciated by all for its unmistakable fragrance and its medicinal properties. In this article, we will discover the techniques for growing peppermint, both for planting it in a pot and in the garden or yard. As always, we will also see the characteristics of the plant, the suitable climate, and the right time for direct sowing. Lastly, we will analyze the methods of reproduction and propagation, along with the proper care to make it grow healthy and flourishing using only organic methods.

But first, as usual, let’s explore the origins of this herb and its spread around the world.

Origins and Spread of Peppermint

Peppermint, scientific name Mentha × piperita, is a perennial herb belonging to the botanical family Lamiaceae (or Labiateae). In reality, this type is a natural hybrid between two wild mint species, Mentha aquatica and Mentha spicata.
It was discovered and classified in 1696 by the English botanist John Ray, who noticed it for its intense fragrance. The cultivation of peppermint, also known as peppermint, quickly spread throughout Europe and the rest of the world, except for tropical regions. The plant achieved great success due to its high content of essential oil. From this oil, menthol is extracted, a substance still widely used in the pharmaceutical, confectionery, and liquor industries. You can find a small package of organic peppermint essential oil here.

The Peppermint Plant

The Stem

Peppermint is a plant that can grow up to 70 cm in height. It has an upright or ascending stem with a square cross-section, slightly hairy, and reddish in color. It grows stoloniferously, meaning it emits several lateral branches that sprout from axillary buds near the plant’s base. This way, the plant elongates along the ground, manages to produce new well-developed roots and leaves, from which new seedlings are generated. Due to this characteristic, peppermint is a very prolific plant.

Leaves, Flowers, Fruits, and Seeds

Peppermint leaves are opposite, ovate, pointed at the apex, and serrated along the edges. They have a deep green color and are lighter on the lower surface, where the veins and glands containing essential oil are evident.
Peppermint flowers are very small, with a purple calyx and a pink-violet corolla. They are clustered in long cylindrical spikes located at the top of the branches.
The flowering period of the plant occurs in late spring/early summer when daylight hours are abundant (14-16 hours). For this reason, peppermint is considered a long-day plant. The fruits, achenes, are small and oval, with a brownish color. They contain the seeds, which, however, have low germinability. We will see shortly what this means for the plant’s reproduction.

Varieties of Mint

Peppermint can be divided into additional varieties. The most appreciated ones are:
Mentha piperita officinalis forma rubescens, better known as black mint. It is a very hardy plant, with a dark stem and leaves with reddish reflections. It is rich in essential oils.
Mentha piperita varietà officinalis forma pallescens, or white mint. It has white flowers, a green stem, and lighter leaves. A very valuable essential oil is obtained from these leaves.

Peppermint Cultivation

Climate and Sowing Period for Peppermint

The peppermint plant adapts well to any cultivation climate. It can be placed in both sunny and shaded positions. It is a plant that thrives both when cultivated in a pot and in open ground. In the latter case, as it is a perennial plant, it should be placed in an external location in the vegetable garden or yard. This way, the plant will not interfere with annual crops. It may be beneficial to associate it with other perennial aromatic plants we have already learned about, such as sage, oregano, and rosemary.
To start peppermint cultivation, you will need to get some seeds, preferably from organic agriculture. The ideal direct sowing period is from the end of February to May.

Growing Peppermint in a Pot

For growing peppermint in a pot, you will need to choose a large and deep container filled with good soil. For further specifics on pot cultivation, you can refer to our article dedicated to balcony gardening.
The seeds should be sown thinly and covered with a thin layer of soil. Watering should be consistent but not excessive until the seeds germinate. Therefore, the soil should always be kept moist but not waterlogged. To improve water absorption, it is recommended to use terracotta pots.

Keep in mind that the plant grows vigorously in pots, so you will need to repot it annually.

Growing Peppermint in the Garden

As for growing peppermint directly in the soil, more attention should be given to the soil’s consistency. It should be well worked and fertile, rich in organic matter. This can be achieved, for example, by adding the result of home composting. The plant requires a presence of potassium in the soil, which can be obtained by fertilizing before sowing, using a moderate amount of wood ash.
Clayey soils should be avoided as they promote water stagnation, which the plant dislikes.

Irrigation

Whether grown in pots or in the ground, peppermint will need regular irrigation, especially during the summer months. A precaution to take when watering is to avoid wetting the leaves directly. This is for two reasons: first, water evaporation causes a loss of essential oil content, and second, direct contact of the leaves with water can cause leaf yellowing.

Propagation by Cuttings

As mentioned earlier, peppermint seeds generally have a low germination rate. Additionally, the plant can easily hybridize with wild species that may be present nearby. For these reasons, if you already have a plant (or have access to one), it is preferable to reproduce it through cuttings. This can be done in March and April. Take a 20 cm long vegetative apex, remove the basal leaves, and place it in water for a few days to promote the emission of new roots. Then, place the cutting in a pot with a diameter of 10-12 cm, filled with a mixture of soil and sand in equal parts, and make holes with a stick or pencil. The soil should be slightly compacted and kept constantly moist. It is recommended to keep the pot in a more shaded position initially. The first new small shoots indicate that the cutting has been successful. After their appearance, the pot can be placed in a sunnier area. When the plant has produced vigorous shoots, it can be transplanted into a larger pot or directly into the ground.

Propagation of Peppermint by Stolons

Even simpler is the propagation technique by stolons, which are the basal branches that the plant naturally emits. Stolons can be taken from adult plants. In the spring, they should be planted in the soil or a pot at a depth of about 15 cm. The stolon is already equipped with roots, so if you have adult plants and want to multiply them, this is an excellent method.

Harvesting and Preservation

Peppermint, in home cultivation, can be harvested fresh all year round, as needed. However, the best time for harvesting is summer when the plant is in full bloom and the essential oil content is at its highest.
If you want to harvest it abundantly during this period and preserve it, you can dry it in a well-ventilated and shaded place. Even when dry, peppermint retains its aromatic properties.
We will dedicate further study to the beneficial properties and uses of this plant. The subject is so vast that it deserves appropriate treatment.

Biological Pest Control

Peppermint is generally very resistant to attacks from pests. One of the few pests we need to keep under control are snails, as we have already mentioned. These creatures are quite fond of this plant.
More troublesome is the possible presence of a fungal parasite: Puccinia menthae. This fungus finds ideal conditions for proliferation when there is a lot of moisture or water stagnation. It causes a kind of rust, which manifests itself as reddish spots and swelling on the leaves. The spots then evolve into blackish stains and leaf withering.
When we notice the presence of Puccinia menthae, the only thing we can do in biological defense is to remove the affected parts of the plant, making sure to aerate the canopy more and reduce water stagnation.

Peppermint: Cultivation in Containers and Vegetable Garden

Peppermint is a highly popular aromatic plant. If you're interested in growing it, you can do so in containers or directly in the open field, employing solely organic methods for cultivation.