We fertilized late in the spring and added iron last week. A mixed cool season and warm season lawn creates some difficulties. The cool season fescue should receive less fertilization and be allowed go dormant in the heat of summer, while the bermuda grass needs to be fertilized and grows best in the hot weather. Keeping both healthy is difficult. Fertilizer needed by the bermuda creates increased disease susceptibility in the fescue when the weather is hot.
Water management becomes especially critical.
As far as fertilization, apply a light application of fertilizer to the bermuda grass once or twice a month through the summer. The most important constituent of the fertilizer for growing grass is nitrogen. Other nutrients are needed as well, but the nitrogen is needed in the greatest amounts. Apply fertilizer so that one-half pound of nitrogen is applied per 1000 square feet with each fertilization. If the fertilizer contains 10 percent nitrogen, you will need to apply 5 pounds of the fertilizer per 1000 square feet to achieve the rate of one-half pound nitrogen over this area.