Media Test Review
This media test is from some hanging baskets. The test was taken to check the basis for poor plant growth. The crop was 6-8 weeks old. To start, the pH of this test is low, especially for plants that have been growing for this length of time. The grower is acidifying, and needs to take a break to help raise the pH at least one full point. A pH of 6.2-6.5 is more appropriate. Associated with this low pH is the high phosphorus level. While the level is not near the toxic range, the level is high and the addition of more phosphorus will probably not be necessary for the duration of this crop. It is very possible that when the grower resumes acidifying the irrigation water, nitric or sulfuric may be the acid of choice. Since another soil test would be recommended before beginning to acidify again, a decision can be made at the time.
Source: • Minnesota Commercial Flower Growers Bulletin Vol. 43 No. 2