Fertilizing Cool-Season Pastures in May
Most pastures have good soil moisture from spring rains. Fertilizing now might help you take advantage of that moisture for increased grass growth.
One key to profitable fertilizing of pastures, though, is to time fertilization to stimulate grass growth to occur 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 spring most pastures received abundant rain. These pastures should be able to continue to grow longer into summer if soil fertility is adequate. To take advantage of this extra soil moisture, fertilize cool-season pastures with 30-60 lb of nitrogen per acre between now and Memorial Day to gain extra summer forage.
To make this May fertilizing work best, it helps to graze pastures moderately before fertilizing. 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 slowly.
Would it be smart to fertilize again in May if you applied nitrogen earlier this spring? Normally I'd say no, especially with nitrogen so expensive, but if you applied just a light amount earlier and already have grazed off most of the grass, a second application might be beneficial, similar to the multiple nitrogen applications used on irrigated pastures.