Summer 2026 Newsletter

Last year, this newsletter asked whether California should develop state-specific tree quality standards or a tree quality certification program. That article shared perspectives from California growers and sparked discussion about potential benefits and challenges.

Evaporation is the process by which water turns into vapor from a surface. After an irrigation or precipitation event, water evaporates from the growing media, soil, and wet plant surfaces. Conversely, transpiration refers to water traveling through a plant’s roots and vascular system and turning into vapor inside the leaf mesophyll, before leaving to the atmosphere through stomata.

In California nursery production, light is one of the most important environmental factors influencing crop timing, plant quality, and uniformity. While the state is known for high annual solar radiation, many greenhouse operations still experience periods, especially from late fall through early spring, when natural light is not sufficient to meet the needs of certain crops. Shorter day lengths, frequent coastal fog, and prolonged cloudy periods can significantly reduce Daily Light Integral (DLI), particularly in propagation and liner production systems. 

Controlled release fertilizers (CRF) are granular fertilizers that have been coated with sulfur or a polymer. These products have been developed to allow a slow release of nutrients into the root zone throughout crop development.  In the following article we will describe several characteristics of CRFs that should be understood and various cultural practices that should be implemented to optimize nutrient use and minimize nutrient leaching when CRFs are used as part of a fertilization program.

Producing high-quality vegetable transplants requires careful fertilizer management to ensure sufficient growth and uniform plant development while minimizing input costs and nutrient losses. With rising fertilizer costs and regulatory pressure to decrease nitrogen pollution in California, efficient fertilizer usage is increasingly important. 

The California Department of Food and Agriculture confirmed the presence of Hercinothrips dimidiatus, also known as aloe thrips, in Ventura, San Diego, and Santa Barbara counties. The CDFA assigned aloe thrips a B rating, which means they determined the pest is of known economic or environmental detriment. B-rated pests can enter the state if the receiving county agrees to accept them. You can read more about B-rated pests here. 

One of the strengths of UC Cooperative Extension is that each advisor’s program is grounded in local conditions while still benefiting from collaboration across the state. There is a great deal to learn simply by observing how experienced advisors approach their work.