Cool-season grasses like orchard grass, timothy, and tall fescue have been the most often cultivated plants for hay. Every one of these grass varieties has a high nitrogen (N) fertilizer need. A common suggestion for N fertilizer is 40 lbs of nitrogen per ton for predicted hay production. A soil test helps you determine how much phosphorus to apply; typically, 20-40 lbs per acre can boost legumes production in most hay fields.