Pteronia incana grows well in areas with dry, hot conditions in sandy loam to clay-rich soils with the presence of moderate to coarse sand particles, and a pH of about 5.5.

Pteronia incana is propagated with its relative, P. paniculata, at the Karoo Desert National Botanical Garden, using the same propagation techniques. This species does extremely well when propagated by seed. Seeds are collected in autumn, stored and sown in summer. Use a mixture of sand and sifted potting soil at a ratio of 50:50. Prepare germination trays with good drainage, place coarse bark chips or any coarse particles that will encourage drainage, in the trays. Firmly place seeds on the growth medium and cover them with fine soil particles to avoid being washed away when watering. Ash bush seeds are tiny and should not be buried under the soil when sowing them. Water the seed trays with a fine spray, or mist sprayer, which is preferred for watering tiny seeds. Place trays in a semi-shaded area, keep them moist all the time, and not damp, until germination takes place. Pteronia incana normally germinates in a period of about 2 to 3 weeks, on average.

After germination, reduce watering and allow aeration through the soil. Transplant the seedlings about 3 months after germination. Use sandy loam soil for transplanting, with the addition of organic fertilizers or well-decomposed compost. Do not apply too much of the nutrient supplements to avoid introducing soil-borne diseases to the plants. Handle roots carefully when transplanting and keep seedlings in a semi-shaded area after transplanting, until they are well adapted to their new conditions. When seedlings are well-established, move them to a full sun area before planting into an open space in the garden.

Propagation by cuttings has not being tried on this species at the Karoo Desert NBG. However, one of the relatives, P. aspera is being easily propagated by cuttings at Kirstenbosch National Botanical Garden. Cuttings are done throughout the year. About 30 mm to 60 mm of softwood to semi-hardwood cuttings are made. Make a cutting just underneath the node and dip the cuttings into a rooting hormone that is suitable for semi-hardwood cuttings. Use coarse river sand as a cutting medium, a ratio of 70% river sand and 30% peat or fine potting mix will support the growing of cuttings. Place cuttings in a glasshouse or misting unit with a heated bench. When cuttings have rooted, apply the same procedures as those described above for the transplanting and hardening-off of seedlings.