Monsonia speciosa is best cultivated from seed. "Seed capsules" (dry fruit splitting up into five 1-seeded parts, when ripe) are long and thin, resembling Pelargonium seed capsules. The elongated seed capsule will start to split longitudinally when the seeds reach maturity. Seeds take nearly two months after flowering to mature. Once the seed capsule is dry (pale brown colour) and starts splitting open, seeds must be harvested as soon as possible otherwise they are likely to be blown away. Seeds are spear-shaped with a corkscrew tail attached to them.

Seed can be sown at most times of the year. Avoid very hot weather (January/February). Sow the seeds in a flat seed pan. Ensure that there is adequate drainage in the bottom of the seed pan. If the seeds stand in too much water, they will more than likely rot. The best medium to sow the seeds in is coarse sand and a loam mixture with one part sieved compost. On top of this mixture, sprinkle a thin layer of coarse river sand, 5 mm in depth. Sow the seeds on this mixture and cover them with a similar sand topping to a depth of 5 mm. Ensure the sand topping is firmed down. Keep the area weed-free and water every second day. During very hot and dry weather water daily, preferably in the early morning when it is cool. Ensure, when watering, that the seeds are not blasted out of the soil; gentle watering is advised. Ensure that the seed trays are positioned in a partly sunny area. The ideal is morning sun only. Do not sow the seeds too deep. If sown too deep, they will be smothered and probably will not germinate. Under ideal conditions, seedlings will grow rapidly. Plant the seedlings out when they are 30-50 mm high.

Monsonia speciosa flourishes in well-drained, loam soils. It can also be grown successfully in compost-rich soils, but the medium must drain well. They are most effectively cultivated in groups in the garden. Remember to plant them in a sunny position, otherwise they will not flower properly.

A word of warning - great care must be taken not to plant this species in heavy clay soils.