Native flower plantings under Minnesota solar panels boost insects and cut costs

Researchers found that seeding native wildflowers and prairie grasses beneath two Minnesota solar farms tripled insect numbers and increased native bee populations twentyfold.

Two solar installations in Minnesota were built on former cropland and, instead of the usual gravel or mowed turf, were seeded with native wildflowers and prairie grasses. Argonne National Laboratory researchers returned to the sites for five years, documenting a threefold rise in overall insect counts and a twentyfold increase in native bees, along with more butterflies, wasps, hornets, and 73 bird species. Landscape ecologist Lee Walston attributes the success to the higher mounting height of the panels, which permits richer understory growth without shading the panels.

The taller design added minimal expense, while maintenance needs dropped sharply after the plants established. A 25-year cost comparison placed native seed mixes at roughly $14,150 per acre, cheaper than turf ($16,800) and gravel ($25,000). Although the findings prove the ecological benefits, pollinator habitats exist on only about 24,000 of the roughly 600,000 acres of U.S. solar farms, and broader industry adoption may hinge on willingness to invest in taller structures.