Science
In 1938, Dennis Hoagland and Daniel Arnon, at the University of California, Berkeley, published a nutrient formula that still underlies many commercial concentrates sold today. Nearly ninety years later, researchers are still refining the details: the right nitrogen ratio at each growth stage, how electrical conductivity affects micronutrient uptake, and the role root oxygenation plays in calcium absorption. Plant physiology moves slowly, but it moves. The articles in this category track that progress and explain the mechanism behind what works, for growers who want to understand before they apply it.