How to grow Cape Primrose

Keep moist bright but cool and well ventilated

Streptocarpus will do well as a house plant on a north facing window, with no direct sunlight and enjoy a temperature of about 20C. As with most house plants it is best to improve the humidity around the growing plant. This can be most easily done by standing the clay pot in a tray of moist gravel. However do not let the plant stand in water or it will rot.
Streptocarpus need less water in the dormant season. If possible use rain water tepid or at room temperature

Streptocarpus as a house plant does not need much fertiliser. Use liquid tomato fertiliser once a month only in the active growing and flowering season, and not at all when approaching dormancy or when dormant

Very fine seeds, sow carefully on surface of compost. water from the botton or with a fine spray. Cover germinating seeds by placing the pot in a plastic bag
Streptocarpus can also be sown onto moss.
Break up a few hand full of sphagnum moss and place it in a bowl. Pour on boiling water and leave it to soak until it is cold. This will kill any weeds in the moss. In a pot place seed compost and top off with the sterilises sphagnum moss, that you have chopped up to give a fine texture. Sow the seed finely on top of the moss. Place in a plastic bag or in a propagator.
Sowing seem may produce plants that do not come true to the parent plants

Plants can also be grown from leaf cuttings, this will ensure that the new plant is the same as the original.
Choose a healthy, mature leaf and cut it from the plant close to the base. Prepare a sed tray of free draining compost by adding grit or vermiculite. Water the compost
Cut the mid vein out of the leaf by running a knife close to the vein making two crescent shapes of the remains leaf tissue. Make a shallow rut in the seed tray, the length of the leaf, and press the leaf into the compost, on edge, with the cut edge into the compost. Press the compost so it is in contact with the leaf tissue.
Cover with a propagator lid or use some sticks and a plastic bag so the bag does not touch the leaf. Keep this warm, 20C and after a few weeks, tiny plants will start at the veins of the patent leaf

For optimal germination, soil temperature should be a minimum of 20°C / 68°F.

Transplant when seedlings are large enough to handle into a mixture of perlite and potting compost.
Streptocarpus do best in not over fertile growing compost. ‘Dilute’ ericaceous compost with leaf mould and add drainage and air with perlite
Do not grow in direct sun

Cape primrose is tender, so ensure you wait until all danger of frost has passed in your area before considering planting outside - as a guideline, the minimum temperature outside should be approximately 13°C / 55°F.

Streptocarpus hybridise readily and the seeds are found in twisted seed heads that in the wild would be dispersed in air currents, so the seeds are very fine.
Streptocarpus may not come true to seed but it can be fun to try to make new hybrids. Harvest when the seed pod is brown and dry

Sow at once on a layer of fine moss at 70C

These estimates for how long Cape primrose takes to sprout, grow and harvest are from real observations from real gardeners, right around the world.

‘Cape’ in Cape Primrose refers to the Cape of Good Hope in South Africa. Streptocarpus are native plants to South Africa

Streptocarpus hybridise readily to produce many colour variations. Newer hybrids also have smaller less brittle leaves than the native plants

Streptocarpus

Streptocarpus Lindl.

¹ Missouri Botanical Garden