Soil Testing Programs Tissue Testing Programs United Soils, Inc. offers several testing packages to meet specific needs. USI can test for the following Grid sizes: 1.1 / 2.5 / 3.3 / 4.4 / 5.0 / 6.6 / 10 / Perimeters Only Reference the list below to see available packages: Test # S1: pH, P1, K, O...