Post-Bloom Nutrition: As California tree crops move out of bloom and into early fruit development, nutrition strategies shift toward supporting crop set, nut fill, and long-term orchard health. In a recent Agronomic Minute, Dylan Rogers, Sales Account Manager for AgroLiquid, outlined what growers should be thinking about during the post-bloom window.
Rogers explained that post-bloom and petal fall applications often follow a familiar pattern across many permanent crops. Early in the season, calcium and nitrogen products are typically the first nutrients introduced through the irrigation system, followed by UN32-type products. As the season progresses, potassium applications ramp up to support crop development, nut fill, and overall quality.
The transition from bloom into fruit development is a critical decision-making period. Once pollination has occurred and crop set is visible, growers can begin adjusting fertility programs based on expected yields. Rogers noted that strong crop set allows growers to estimate nutrient demand using historical yield data, while lighter sets or weather-related challenges may require adjustments.
However, Rogers cautioned against cutting fertility programs too aggressively in low-crop situations. “We’re influencing next year’s crop,” he said, emphasizing that completely pulling back nutrition can hurt bud development for the following season. Maintaining a baseline fertility program helps protect long-term productivity.
Phosphorus timing is another key consideration during the post-bloom period. Rogers prefers an early-season phosphorus application as trees leaf out, when feeder roots are actively growing below ground. Even when soil phosphorus levels appear adequate, availability can be limited by tie-up from gypsum or other soil constituents.
He also recommended a second phosphorus application in early summer, around June, when bud differentiation occurs. Adequate phosphorus during this window supports the development of fruiting buds and helps set the stage for next year’s crop.
For more information on post-bloom fertility strategies, visit AgroLiquid.com.