Caroline Gengo, a UC Master Gardener from Yolo County, outlined on Apr. 10 several ways gardeners can help their plants withstand heat waves and high temperatures. As people seek relief indoors or near water during hot weather, Gengo said that most garden plants cannot move and must cope with the conditions where they are planted.
Gengo explained that plants cool themselves through evapotranspiration, a process in which water evaporates from small pores called stomata on leaves. She recommended watering deeply and more frequently during hot spells to support this process. “Watering early in the morning or late in the evening, when temperatures are cooler, will ensure that the water has a chance to seep into the soil rather than evaporating,” she said. Adding mulch can also help retain moisture by reducing evaporation from the soil surface.
Some plants are especially vulnerable to heat stress, particularly young or newly transplanted ones without established root systems. Gengo suggested these may require extra watering or shade cloths for protection: “These plants may need more frequent watering or, in some cases, a shade cloth to reduce temperatures around them.” She also advised against fertilizing before heat waves because new growth is sensitive and dries out quickly.
The University of California Agriculture and Natural Resources (UC ANR), which manages Cooperative Extension services as part of the University of California system according to its official website, supports sustainable gardening practices like those described by Gengo. UC ANR secures funding through public contributions according to its official website and promotes resilient ecosystems and economic vitality according to its official website. The organization operates nine research and extension centers across California’s diverse ecosystems according to its official website.
UC ANR is recognized for connecting research with community needs according to its official website. It conducts over 33,000 educational events each year with participation from more than 18,000 volunteers according to its official website.
As climate patterns shift toward warmer weather extremes, advice such as Gengo’s may become increasingly important for home gardeners looking to maintain healthy gardens.