Reproduction by seeds

By: Troels Andersen

Tropica produces several of the major genera from seeds - such as Alternanthera reinickii "pink"Lobelia cardinalis, and Ludwigia glandulosa.

Producing plants from seeds has many advantages - seen from the end-user's point of view, it produces many plants in each pot and the plants tend to be compact. But more important is the fact that plants produced in this way grow on the same mineral wool from the time the seeds are put onto it to the time the plants leave the nursery. This makes them stronger and more capable of survival as the roots are not disturbed during the growing process and, as will be familiar, healthy roots are the basis for prolific growth and a high level of adaptability to new environments.
Tropica has several members of staff who possess great experience in producing plants from seeds - from the time a new plant is ready for production to the weekly delivery of thousands of plants propagated in this way. The process can be outlined as follows:

Mother plants
The first step in the process is to propagate mother plants that can supply seeds for production on an ongoing basis. It is particularly important in this connection to be familiar with the factors that promote flowering, such as light, the length of the day, and temperature, but also to ensure a stock of healthy, robust mother plants.

The species produced from seeds by Tropica are all autogamous, which means they pollinate themselves - but some of them can be helped to yield more seeds through manual pollination. Tropica's staff therefore play 'birds and bees' and harvest pollen manually from the stamens and place it on the style. This increases both the number and size of the ovules on the mother plant.

Harvesting seeds from mother plants
When the mother plant reaches the right age, flowers and forms ovules, the next challenge is to determine when and how the seeds should be harvested. The majority of our seeds are harvested from the pods - some plants are cut and laid to dry with stems, leaves, and pods so that the seeds can mature as the plant dries. With other plants, seeds can be harvested direct from the pods on the plants. When the seeds have been harvested they must be threshed to separate them from their capsules and then passed through sieves to remove the remains of the plant and capsules. Finally, it is necessary to make sure the seeds are absolutely dry before storing them.

Seed germination
Some seeds germinate easily when spread on mineral wool under normal light, nutrition, moisture, and temperature conditions in the greenhouses. Other seeds must be treated in order to promote their ability to germinate. Temperature and moisture are usually decisive in determining whether a seed will germinate. Light is a third factor - both its composition and the length of the day.

From seed to sales plant
During the time the seed has germinated to the time Tropica has a plant ready for sale, the most important factor is to adapt moisture levels on an ongoing basis (newly-sown pots are put into a tent), but otherwise, growth conditions for these plants are comparable to that of the other plants in Tropica's production. It typically takes eight to ten weeks from the time the seeds are placed on the growth medium to the time there are many plants in each pot ready for sale.

If you have any questions or comments on Tropica's producing plants from seeds, you are welcome to contact us at