Fertilizing Cool-Season Grasses in May
One key to profitable fertilizing of pastures is timing fertilization to stimulate grass growth for when you need it. We often fertilize cool-season grass pastures like bromegrass in early April to get a good boost in early growth. By June or July, though, these pastures run out of both moisture and fertilizer. Add in hot temperatures and their growth nearly stops. This may not be the circumstance this year.
Most pastures received abundant rain this spring and should be able to grow longer into summer if soil fertility is adequate. To take advantage of this situation and grow these cool-season pastures longer into summer, fertilize with 30-60 pounds of nitrogen per acre between now and Memorial Day.
This May nitrogen application works best if pastures are moderately grazed first. This seems to encourage more thickening of the grass stand and slightly reduces the number of seed stalks produced. Don’t graze too short, though, or plants will be stressed and regrow more slowly. Would it be smart to fertilize again in May if you applied nitrogen earlier this spring? Normally I would say no, especially given the current cost of nitrogen, but if you applied just a light amount earlier and have already grazed off most of the grass, a second application might be beneficial, similar to the multiple nitrogen applications used on irrigated pastures.