Thyme is a popular addition to the herb garden - but is it hardy? Unfortunately, there is no general answer to this question, because breeding and variety determine how the plant reacts to sub-zero temperatures. When hibernating, a few factors must therefore be taken into account. Especially if the plant is to remain outdoors. Whether protection is necessary and how it should be designed depends on the climate and variety.
Hardy varieties
If you want to leave the thyme - or thymus, as it is also called - outdoors all year round and protect it as little as possible in winter, you should choose a variety that is hardy or one great frost tolerance having.
This includes:
- Wild Thyme down to -30 °C
- Upholstery thyme and cascade thyme down to -28 °C each
- Common thyme, fragrant thyme and wild thyme down to around -22 °C each
Unless these varieties are planted in a particularly harsh climate or if severe temperature drops are to be expected, they hardly need any protective measures during the winter. Only the location should be optimally tailored to the needs of the plants.
This includes for the successful culture and a corresponding overwintering:
- sufficient light: The thymus should be illuminated for at least four to six hours a day in summer. In winter it should also not be completely in the shade, as it is an evergreen plant that needs light.
- Reduce temperature fluctuations: The robust Thymus species are less disturbed and weakened by the frost and more by temperature fluctuations. A very exposed location is therefore unfavorable for successful wintering. Cultivation in planters with a diameter of less than 30 centimeters is also not recommended.
- no waterlogging: The roots of thyme suffer quickly if they are in too moist soil or are even exposed to waterlogging. However, this can also happen quickly in rather dry areas during autumn and winter. In addition to a dry location and adequate drainage, protection against precipitation should also be provided in rainy areas. For example, needle sticks, which are distributed around the thymus, are suitable for this.
- Avoid marjoram: If marjoram and thyme are planted close together, they hinder each other's growth. The plants go into hibernation already weakened. This increases the risk of the thymus dying-even if it's hardy.
Varieties sensitive to frost
cultivated forms of thyme are clearly more sensitive to frost. Spanish kitchen thyme, for example, only tolerates temperatures down to -10 °C. Cumin thyme, lemon thyme, hybrids and variegated varieties are also not suitable for overwintering outdoors. If you are unsure which variety it is, you should overwinter the plant indoors to be on the safe side.
winter protection
In the open air
If the thyme was planted outdoors and it is not a hardy variety, or extreme sub-zero temperatures are to be expected, the following protective measures can be useful.
- Cover ground: Leaves, straw and brushwood protect against frost and also help to avoid abrupt temperature fluctuations.
- Protection against moisture: In heavy snowfall or continuous rain, the ground can quickly become very wet. As mentioned, needle brushwood provides some protection against precipitation. An alternative are foils that cover the floor and can keep water away in the immediate vicinity.
- Sheath Plant: Thymus is evergreen and therefore needs sufficient light during the winter. If the temperature drops very sharply, it may still be necessary to protect leaves and twigs. For this purpose, the plant can be covered with fleece, jute or garden foil. On warmer days, however, the cover should be accepted so that the plant receives enough light.
hibernate
In the bucket
If the thyme is grown in a tub and is to be overwintered outdoors, it definitely needs appropriate protection. Because even hardy varieties with a high frost tolerance are only insufficiently protected by the smaller soil volume in the planter. The following points should therefore be observed.
- Light: The plant needs a bright and sheltered place. The south side near a wall or wall is ideal.
- Insulation from below: To protect the roots and soil from frost, the planter should be placed on a thick piece of wood or a thick styrofoam board. This also applies if the bucket is on the balcony and is therefore already elevated.
- External protection: The bucket must be covered to compensate for the small volume of soil and to allow less frost to penetrate. Suitable materials are base foil, jute, polystyrene fleece, fleece or special frost protection covers for plants.
- Planter size: If the plant pot has a diameter of less than 30 centimetres, the protective measures described are usually not sufficient. The more soil volume is available, the better the plant is armed against the cold.
in the house
Overwintering indoors is the safest for the thyme and also the easiest, as only a few things need to be considered. The following factors are necessary.
- a sufficiently bright location: Window sills are ideal. A bright room, hallway or basement with windows is also sufficient.
- a frost-free place: The spicy-aromatic herb can be overwintered cold or warm - the main thing is that it is frost-free. Therefore, the kitchen is just as suitable as the basement.
- adjusted watering: The warmer and lighter the plant is, the more water it needs. The substrate should generally never dry out. With a warm and bright hibernation, however, watering is of course more necessary than in a cool cellar.
Our tip: The cool hibernation means an invigorating break for the plant. If possible, varieties that are not hardy should also be cooler in winter.