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Basil is one of the most popular kitchen herbs and is not only used to eat, but also to repel insects. However, if it develops black spots, the care should be thoroughly checked.

In a nutshell

  • Basil can get black spots from cold weather
  • Burns are possible in summer
  • Cold damage and care errors are the most common causes of black spots
  • Growing basil yourself can prevent problems


Above all, damp, cold air does not do the basil any good and makes the aromatic plant susceptible to fungal infestation, which can cause black spots. Due to its origin, the herb is comparatively sensitive. Even transport in a poorly insulated truck can be enough to cause cold damage to the plant.
The difficulty here is that black dots usually do not appear immediately due to a temperature that is too low, but with a time delay. The cause can therefore lie long before the purchase. While the basil still looks fresh and healthy in the supermarket, problems quickly arise in the kitchen at home.
However, this can be avoided by taking appropriate action. These include:

  • Grow your own basil
  • buy from nurseries and not from supermarkets
  • Avoid temperatures below 15 °C

Tip: Even in summer, night-time temperatures can drop below 15 °C. Therefore, for safety reasons, the plant should be kept indoors or at least placed indoors at night.


High temperatures, or more specifically sunlight, can also cause black spots on the leaves of basil. Instead of fungi or cold damage, however, it's burns.
The risk of this is increased when dewdrops or rainwater collect on the leaves. These drops act as lenses, concentrating sunlight. As a result, localized burns not only occur more quickly, but also become stronger and darker in a shorter time. It is not only difficult for laypeople to tell the difference between cold damage and burns. In any case, the points are similar and require a review of the culture conditions.


When the growth is weakened, fungus can spread faster and easier, creating black spots. In addition, the chances of a full recovery from damage are reduced. With the right measures, however, it is possible to prevent problems on the one hand and to save the plant in the event of damage or infestation with pathogens on the other. The measures are:

  1. Recognize reason: Is the location too cold or is there too much direct sunlight hitting the leaves? Is there high humidity? Even these simple questions can provide information about whether there is a problem with the culture. If the care conditions are already optimal and the basil was newly purchased, it must be assumed that the basil was damaged during transport or was previously stored in an unfavorable manner.
  2. Care: Above all the correct pouring are to be considered. Because if the watering is done incorrectly, problems can quickly arise. Appropriate fertilization is also important. Coffee grounds, horn shavings, nettle manure or compost are suitable home remedies. However, you can also use special herb fertilizers. The additional nutrient supply should be weekly from May to September.
  3. Protection: The Mediterranean spice does not tolerate abrupt changes. Changing the location suddenly or peeling off the film too quickly can also cause problems. Slow changes are better. Remove packaging piece by piece and slowly move the planter to another position.
  4. Harvest and cuttings: Comparatively strong harvesting in combination with the right care is ideal if black spots are already present. However, removing the affected leaves only prevents the spread of fungus. You cannot prevent burns or black spots caused by temperatures that are too low.


Especially with regard to watering, the plant is prone to care errors. Therefore, you should consider a few points:

  • Water must be at room temperature
  • Watering should be done from below
  • Avoid waterlogging
  • use soft water with a low lime content
  • water frequently but in small amounts

Tip: Tap water is often very hard. Better options for watering the basil are rainwater, pond water, aquarium water or even stale or filtered tap water.


Ocimum basilicum - as the Mediterranean herb is called in botanical jargon - is rarely attacked by parasites. In fact, the plant is actively used against pests and is therefore wonderfully suited to mixed plantings as a natural defense.

Only snails use the leaves as a food source. Black dots do not have to be assumed to be a pest infestation.

frequently asked Questions

Why do homegrown basil rarely have black dots?

Herbs bought in the supermarket have already been transported for a long time. This can lead to a build-up of moisture and fluctuate in both temperature and light conditions. It is therefore not surprising that the plants often show damage or even die after a few days. This problem does not exist with self-grown plants.
In addition, a correspondingly resistant variety can also be selected for your own sowing.

When can the Ocimum basilicum be outdoors?

When a sheltered location is chosen and temperatures are above 15°C. Direct midday sun should be avoided. East and West are therefore ideal. Since the plant suffers quickly in cooler temperatures, strong winds should also be avoided.

Saving the basil plant - is it possible?

Even if black spots appear on the leaves of the basil, the plant can still be saved. The removal of the affected parts of the plant and the adaptation of the care is often sufficient. A change of location can also be useful.

What must be considered when combating?

If the basil leaves are still to be consumed, no harmful substances may of course be used. As a precaution, discolored leaves should no longer be eaten, as the cause could be fungi.

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