More low-germination and coated seed will be marketed this year to stretch the short forage-seed supply, says Dan Undersander, University of Wisconsin extension forage specialist. And that may increase a grower's costs, he adds.
“What counts is not the weight in the bag, but how many pounds of live seed you buy,” Undersander warns. Pure live seed (PLS) can be figured by multiplying the percentage of germination with the percentage of purity, which can be found on the seed bag (multiply by 100 to get the decimal point in the right place).
“Also, we see this more in other species than in alfalfa, but the germination will go down when seed is short.” If germination is at 80% rather than 90% or more, “you're buying a lot more seed that isn't live,” he says. “If the coating is 30% of the weight in the bag, that increases your cost per pound of seed. No university research has shown that coated alfalfa seed will germinate better than uncoated seed.”
A bag of seed typically holds 90%-plus PLS. But if germination is 80% and seed is coated (30% inert material), only 56% is PLS in the bag. At $200/bag, cost per pound of PLS goes from about $4/lb to $7.15/lb, he says.