Purslane (Portulaca oleracea) is a resilient succulent, valued for its edible leaves and stems. It adapts well to warm conditions but is sensitive to cold, making understanding its temperature requirements important for cultivation.
Ideal Growing Temperatures
For vigorous growth and optimal leaf production, a consistently warm environment is beneficial. The ideal temperature range for established plants is 65-80°F (18-27°C), thriving best above 70°F (21°C). For germination, purslane seeds require warmer soil, with optimal rates seen when soil temperatures are between 70 and 85°F (21-29°C). Initially, seed germination is best above 86°F (30°C), though this requirement can decrease to 68°F (20°C) as spring progresses.
Thriving in the Heat
Purslane demonstrates exceptional tolerance for high temperatures, often flourishing in conditions that stress other plants. It performs well when temperatures exceed 100 degrees Fahrenheit (38 degrees Celsius). This plant can even endure temperatures up to 122 degrees Fahrenheit (50 degrees Celsius) when provided with sufficient water. Its succulent leaves and stems store water, contributing to its drought resistance.
The plant employs physiological adaptations, such as small stomates and a waxy outer layer, which help reduce water loss. In hot, dry conditions, purslane can utilize Crassulacean acid metabolism (CAM), a photosynthetic process where leaf stomata open at night to conserve moisture. While these mechanisms allow it to endure intense heat, extreme temperatures above 109 degrees Fahrenheit (43 degrees Celsius) may cause leaves to lighten, curl, or wilt.
Understanding Cold Tolerance
Purslane is a tender annual, highly susceptible to cold temperatures and frost. It cannot survive outdoors in freezing conditions, and even chilling temperatures can cause damage or death. The plant is typically killed by the first hard frost of the season. Its inability to withstand sustained cold temperatures means it is cultivated as an annual in most temperate climates, completing its life cycle within a single growing season.
Protecting Your Purslane
Gardeners can use several strategies to manage purslane across varying temperatures and extend its growing period. Seeds can be sown outdoors after the last frost, when soil temperatures consistently reach around 60°F (16°C). For an earlier start, seeds may be sown indoors two to four weeks before the final frost date.
In mild winter regions (USDA Zones 10-11), purslane can remain outdoors, though covering it during cold spells can offer protection. For colder climates, bringing potted purslane indoors before temperatures drop below 40°F (4°C) to survive winter. Indoors, plants benefit from a sunny window and minimal watering, allowing the soil to dry between applications. For young plants, maintaining temperatures above 40°F (5°C) is beneficial, and providing shade cloth can protect them from intense summer heat above 80°F (27°C).