Figures for Weed watch: weed species emergence is based on soil temperature

Karen Renner and Doug Buhler, MSU Crop & Soil Sciences

The relative sequence of germination times for common weeds is shown in Figure 1. Figures 2 and 3 provide more detail on the relative time of emergence of fall panicum, giant foxtail, and large crabgrass (Figure 2), and common lambsquarters, common ragweed, common waterhemp, and redroot pigweed (Figure 3). The narrow, dark bar shown for each weed species in each figure shows the time of peak emergence. The wide broad band depicts the time during which each weed species emerged. This research was conducted in Ames, Iowa (Buhler and Hartzler), which may be a bit warmer than Michigan. However, the sequence of emergence for these weed species would not change. You can see from Figure 3 why common waterhemp is such a problem in Iowa. It starts emerging at about the same time as redroot pigweed but peak emergence is later in the season and waterhemp keeps emerging into August.

Figure 1: Germination times for common Michigan weeds

Figure 2: Time of emergence of fall panicum, giant foxtail, and large crabgrass

Figure 3: Time of emergence of lambsquarters, common ragweed, common waterhemp, and redroot pigweed.