Herbs in the Greenhouse

Spring has begun. The days are longer, and the greenhouse is warmer. Who does not dream of a corner in the greenhouse filled with herbs? There is a lot of great herbs. You probably have your personal favourites.

Here at Spirekassen, we often see some confusion regarding which herbs you can plant in the greenhouse and when. In this article, you can learn more about the difference of various groups of herbs.  

Not everything is suited for the greenhouse

Most herbs don’t like being cultivated on a windowsill in the kitchen for a long period of time. Often, it is possible to purchase pots with herbs in the supermarket, that we often automatically place in the windowsill and water from time to time. ‘Supermarket herbs’ are grown in industrial greenhouses with artificial warmth and light. Supermarket herbs are only suited for a short life, after which they will die. The reason for the plants' short life span is a weak root net. The roots are not robust enough to survive outside of the protected world of industrial greenhouses.

In order to achieve success with herbs in the greenhouse, we must have knowledge of the different types. Every herb has specific cultivation demands.  

Rosmarry

Division of Herbs

Herbs can be divided into two groups. The heat demanding herbs and the less heat demanding herbs. In order for you to get an understanding of the cultivation needs of the herbs, you must look at where the herb is originally from; where it is native. The climate conditions, in its native area, should be replicated for the herb to be able to thrive.  

Herbs that Can Withstand the Cold

This group of herbs can be described as either herbaceous perennial, subshrub or two-year plants. These herbs thrive for several years in a row:

Characteristics of This Group:

• All herbs in this group can be pre-germinated in the greenhouse in March.  
• Start early with the pre-germination, as the seeds might take a while to germinate.  
• This group of herbs can be cultivated in the greenhouse all year.
• It is a good idea to learn about the cultivation needs of every single herb.  

Especially basil needs at least 15-20°C all day and night before the seeds will germinate and thrive. Coriander and basil are so heat demanding, that they thrive the best in the greenhouse. A less heat demanding herb is dill. Although dill will quickly evolve and form seeds in the heat of the greenhouse, dill can get too hot. At the same time it doesn’t like the cold.  

Characteristics of This Group:

• All herbs in this group can pre-germinated in the greenhouse from May.
• The gemination happens quickly, usually after 1 to 2 weeks.  
• This group of herbs cannot be cultivated in the greenhouse all year.