Germinating Calceolaria

Includes the following genera: Calceolaria, Jovellana.

Includes the following species: Calceolaria alba, Calceolaria arachnoidea, Calceolaria ascendens subsp. ascendens, Calceolaria cana, Calceolaria cavanillesii, Calceolaria collina ssp. collina, Calceolaria corymbosa ssp. mimuloides, Calceolaria dentata ssp. araucana, Calceolaria filicaulis ssp. filicaulis, Calceolaria flavovirens, Calceolaria glandulosa, Calceolaria hypericina, Calceolaria integrifolia, Calceolaria meyeniana, Calceolaria morisii, Calceolaria nudicaulis, Calceolaria pallida, Calceolaria paposana, Calceolaria paralia, Calceolaria petiolaris, Calceolaria polifolia, Calceolaria polyrhiza, Calceolaria purpurea, Calceolaria segethii, Calceolaria thyrsiflora, Calceolaria undulata, Calceolaria valdiviana, Calceolaria williamsii, Jovellana punctata.

The germination of most calceolarias is relatively easy, and the only problem they pose is due to the small, dust-like size of their seeds. Due to their size, the seeds must be simply sown on the surface. Light is often reported as required factor for germination. We have not yet run specific tests to confirm it, but due to the fact that the seeds must be sown superficially, they will receive light naturally.

To germinate calceolarias, prepare a finely ground germination substrate with very good drainage (containing 50% vermiculite, sand, or similar). The requirement for finely ground substrate is because if the substrate is rough, the seeds will fall deep between the substrate particles and many will not germinate. Moisten well the substrate before planting. We always prefer to soak the seeds before sowing (24-48 hours), but the sowing is then more complicated. We spay the water with seeds on the surface. Dry sowing also gives good results.

Expose to moderate temperatures (+14C +18C) and light. It is also very important to maintain the substrate humid at all times; to do so one has either to spray it several times a day or one can also cover the seeds with a film of a transparent or milky plastic, but be careful not to increse the temperature too much in this way!

The germination occurs normaly in 8 to 20 days. Transplant the seedlings after about 4 - 6 weeks after germination into the definive containers.

For growth, some species may tolerate less humid conditions and may spend several months in dry environment (check each individual record for watering information), but in general, calceolarias love humidity, light, and air.

During the last seasons we have tested most of the species, and the results are quite similar for the species tested. Right now we are germinating Calceolaria alba y Calceolaria williamsii.

For some calceolaria species (for instance, Calceolaria uniflora), a cold stratification is mentioned in literature as a means of increasing the germination percentage. This may be especially true if you germinate the seeds in a warm environment (+20C, at which standard germination tests are run, or more), however, we have never observed the need for cold treatment when germinating at cool temperatures. If you are in an area where cool temperatures are a problem, putting the container with seeds into a fridge (+4 C) for a couple of days may indeed increase the germination rate.