Gladiolus stefaniae is not more difficult to grow than most other winter-rainfall gladioli. It requires an acid, sandy growing medium such as 3 parts medium-grained river sand, mixed with 1 part fine, acid compost, or finely milled, acid bark. Plant mature corms in 15 or 20 cm diamiameter plastic pots in late summer, at a depth of 2 cm, and provide an initial heavy watering at the same time, to stimulate the appearance of flower buds. Once the flowers have withered, water heavily once per week until mid-spring. The plants need a well-ventilated and sunny aspect, preferably receiving morning sun and afternoon shade. Inland forms of this species can probably tolerate light frost for short periods of several hours. Hand-pollinate the flowers, by collecting ripe pollen (it should be dry and easily removed) from the anthers with a water-paint brush, then dab the brush onto the stigmas of different individuals. Harvest the seeds as soon as the dry capsules begin to split, otherwise they will soon be lost during wind gusts. As temperatures rise markedly towards the end of spring, discontinue watering altogether until late summer, placing pots where they will remain dry, and will not overheat on very hot days.

Offsets form slowly, so separate clumps in late summer at planting time. Propagation by seed is the most feasible method of multiplication. An almost 100% germination rate can be expected from sowing fresh seeds (those harvested and sown directly after they have matured in winter). Germination of fresh seeds typically occurs within 4 weeks. Sow the seeds in late winter, and choose a still day for sowing, as the light, aerodynamic seeds are rapidly whisked away by the slightest breeze. Sow the seeds in deep seed trays, pots or deep seed beds, in an area receiving morning sun, and under protection from heavy rain. Use a light, well-drained, acid, sandy medium, such as 3 parts medium-grained river sand and 1 part fine, acid compost, or finely milled, acid bark. Before sowing, moisten the surface of the sowing medium, using a watering can, fitted with a fine rose-cap. With an index finger, or tip of a trowel, make shallow furrows about 5 mm deep, sow the seeds thinly into the furrows, and cover with 5 mm of sowing medium. Apply a thorough watering with a watering can, and keep the medium moist by watering every second or third day. When the leaves start to turn yellow at the tips in early summer, cease watering altogether and allow the seedlings to remain dry over the summer dormant period. Freshly harvested seeds that have been stored at low temperature in a fridge, should maintain viability for many years. Allow seedlings to remain in the same position for two years, and at the beginning of the third season, lift and plant them into permanent containers. In ideal conditions, flowering usually commences in the fourth season.

The leaves of Gladiolus stefaniae are occasionally susceptible to attack by aphids, and the corms to mealy bugs. Corms are also subject to fungal attack, caused by Botrytis and Fusarium fungi. Provision of a well-ventilated environment, a perfectly well-drained growing medium, and adherence to watering and dormancy procedures, will assist in keeping pests and diseases at bay.