Moss Rose (Portulaca grandiflora)
Even though portulaca is from the purslane family, it is almost the exact opposite to grow. Because portulaca is a succulent, it prefers sandy soil and drier conditions. In zones 5 and warmer, it can be grown in-ground outdoors and makes a beautiful edging, ground cover, or cover crop. Otherwise, keep it potted to bring in over the winter. Tiny portulaca seeds are best started indoors where heat, light, and water can be more regulated. Use a tray and place small clay pebbles in the bottom, then layer sandy soil (typically labeled as cactus soil) on top. The portulaca seeds should be scattered across the top of the soil and very gently pressed down with a tamping tool (or a hand). Avoid covering the seeds as they need light to germinate. Use a spray bottle to mist the top of the soil and water the tray from the bottom. Once the tray has had a good soaking, remove the excess water and cover the top of the tray with glass, cling wrap, a plastic bag, or a dome cover to keep in the humidity. Place the tray on a heat mat and use grow lights just above the covering.
Portulaca seeds are faster to germinate than most succulents, taking about 2-3 weeks to germinate, instead of months. Check soil moisture every few days, adding mist if needed - do not let the soil dry out completely! Once growth occurs, remove the covering and heat mat, and begin to raise the light as it grows. Once all danger of frosts have passed, portulaca can be planted outside.
Pick a sunny place where portulaca can spread. More sun means more flowers. Portulaca is pest resistant and can be planted just about anywhere, though avoid putting it in an area that’s always getting watered. Portulaca needs very little upkeep once established, and will stay green year round. It will flower in warmer months, and like other purslanes, is fully edible.