Growing organic herb seedlings as a discipline in its own right

The little vervain plants still need a few weeks before they can leave their protected nursery in the greenhouse of the organic nursery Neubauer in Erlen TG. There, a woodchip heating system ensures that the temperature does not drop below freezing point. The frost-sensitive plants would not survive that, because they originally come from South America. The nursery, which has been certified organic for over 30 years, specialises in the production of somewhat more specialised young plants. Holderhof has some of its herb young plants produced here, such as nettles, lovage, mint and vervain. In May, the more than 60,000 vervain seedlings move to the Holderhof farm in Ufhofen, where they are mechanically planted in the freshly prepared soil in the open field. In the following summer months, the leaves are harvested and gently dried on site, and used in Holderhof beverages as needed – for example, in the “vervain lemon” BioTea, newly launched by Holderhof. In our climate, professional vervain cultivation only works if the young plants can grow in small pots in a protected environment, supported by LED light during the dark winter months. In order for this to succeed at all and for the many young plants to be ready in time, a lot of know-how is required from the team around senior boss Markus Neubauer.

Vegetative propagation

The propagation of mint or vervain is done vegetatively via cuttings. Markus Neubauer’s staff take these from so-called mother plants. A basic stock of such mother plants, necessary for the start, must be permanently available and is rejuvenated annually by newly grown plants. As early as September, the first cuttings are taken for the following year’s cultivation season, and in about five weeks they grow to the point where they can become cuttings themselves. This continues in several sets until finally the number of seedlings ordered is reached. Apart from organisational effort, a fine hand and a practised eye are needed to cut the small branches of vervain properly from the mother plant. The cuttings are then placed in soil pots with the nursery’s own peat-free soil mixture. As a preliminary stage to root formation, the so-called callus is formed first. In this first phase, the cuttings need sufficient moisture, light and the right temperature. “Finding and maintaining this balance is the prerequisite for successful root formation,” explains Markus Neubauer.

Nettle seeds from the Bernese Oberland

Last year, Markus Neubauer cultivated organic young plants of lovage and nettles on behalf of Holderhof. Unlike mint and vervain, these are sown individually in the soil pots. As a slow-growing plant, lovage is sown as early as August so that it is ready for planting outdoors the following spring. The cultivation of nettles was a special challenge for the organic nursery. Holderhof was the first and so far the only customer to order nettle seedlings on such a large scale. Even the procurement of seeds in organic quality was time-consuming. Markus Neubauer finally found what he was looking for at a small seed breeding company in the Bernese Oberland. Since there was hardly any experience with the crop, however, the nursery first had to clarify the plant’s requirements with small cultivation kits in order to finally create the ideal environment for growth. “If a plant just grows by itself in nature, that doesn’t necessarily mean that it will also work as a crop in a professional cultivation,” explains Markus Neubauer, who is keen to experiment. It has worked nicely for the nettles.

Lovage seedling ready for planting.