Unpredictable weather, spongy soil, and plants that are tender are all common in Iowa during the spring, which can make it a sensitive time for yards according to horticulturists with Iowa State University Extension and Outreach.

They state that the key to controlling crabgrass in lawns is correctly timing a pre-emergence herbicide application. It needs to be applied before the crabgrass seeds germinate. In southern Iowa it is normally applied in early to mid-April. To relieve soil compaction lawns can be aerated, which improves water and nutrient movement, and discourages thatch accumulation. They advise that aerating in April or September allows the grass to recover quickly during favorable growing conditions. If aerating in April, then apply a pre-emergence herbicide afterwards.