Portulaca grandiflora should be planted after the danger of frost has passed. It requires full sun, as its flowers only open in sunlight and close at night or on cloudy days. The species thrives in poor, sandy, or gravelly soil but can also grow in any well-draining soil. While drought resistant, it benefits from moderate, regular watering during hot and dry periods. Poorly drained soils, however, can cause crown rot.

Portulaca grandiflora can be propagated either by seeds or by shoot cuttings.

For seed propagation, the very small seeds should be mixed with sand for easier distribution and sown in seedling trays or directly into well-prepared garden beds in spring or summer. Germination occurs best at temperatures between 24 and 26°C and requires light, so the seeds should not be covered. Seeds typically germinate in 2 to 4 days in ideal conditions, but may take longer in cooler soil. Plants will bloom 12 to 14 weeks after sowing. Seedling trays should be placed in a bright, warm location, as Portulaca is sensitive to cool temperatures and low light. The seedlings quickly grow to about 100 to 150 mm in height and spread around 300 mm wide. In warm climates, P. grandiflora may self-seed in the garden, but direct sowing into the ground is recommended, as the plants do not respond well to transplantation.

Vegetative propagation of this species is done by taking cuttings of plant stems with leaves and nodes (areas where leaves attach to the stem). The stem should be about 200 mm long, with 8 to 12 nodes. Root formation is facilitated by the presence of a node, and the cut end of the stem should be planted in soil, allowing adventitious roots to form at the nodes. New leaves will appear in about 21 days, and applying fertilizer can encourage faster growth.

Portulaca grandiflora needs minimal pruning. The plants self-clean by dropping faded blooms and don’t require deadheading. However, a mid-summer trim can rejuvenate the foliage and encourage flowering into autumn. This plant is ideal as an edging or groundcover for beds, rock gardens, or along walkways. It also thrives in containers, hanging baskets, and can spill over stone walls. Although aphids and slugs can occasionally affect it, Portulaca grandiflora is perfect for poor, dry soils where other plants may struggle.