Media Test Review (1993)
The media test results shown above are from a sample early in a poinsettia crop. The grower isn't experiencing any particular problems, but is running an early test to help monitor the crop and see where the plants may need some nutritional help. As would be expected on an early test, the nutrient levels are generally low. This will be amended as the plants are fertilized.
Source: • Minnesota Commercial Flower Growers Bulletin Vol. 42 No. 3