California Tan Nursery Grit (9996906) is a well-graded, processed sand produced from California sources. Foreign material and dust are removed in a high temperature drying process and by screening. The product is available in two size ranges, and contains mainly natural, sub-rounded to sub-angular particles in the following US sieve sizes: Regular No. 5 to No. 12 (2 to 4 mm) Coarse No. 8 to ¼” (2 to 6 mm)
It is suitable for seed and planting operations requiring clean, free-draining sand. Current cultural practices show that most tree species benefit from a seed cover after sowing. The required thickness of this cover varies, but in general the cover depth should not exceed 1/4″ (6 mm) for small-seeded species and ⅜” (9 mm) for large-seeded species. The main function of the cover is to hold the seed anchored during germination. The cover also protects the seed from direct sunlight and aids the moisture retention necessary for germination. Water and air are readily able to penetrate the sand, but moss and algae growth and the resultant adverse effects on germination and seedling growth are inhibited by the relatively inert sand particles. Crusting, which hinders water penetration, does not occur to any significant extent with California Tan Nursery Grit. Significant crusting often occurs with poorly graded sands. Because it is dry, dense, and evenly graded, California Tan Nursery Grit is easily applied and anchors the seed well. Perlite and vermiculite have proven to be poor seed covering materials because they have a light density and tend to blow off. Because it is chemically neutral it does not interfere with seedling nutrition programs.