Hello,

Here are some references on seeding microclover. The preferred time is late summer to early fall to avoid competition with lawn weeds.  But it can be seeded in spring if you don’t apply crabgrass pre-emergent or broad leaf type weed killers to the turf. Use the same over-seeding techniques as you would with grass seed: https://www.canr.msu.edu/news/tips_for_reseeding_lawns_in_the_spring

Microclover:

https://extension.umd.edu/sites/extension.umd.edu/files/_images/programs/hgic/Publications/non_HGIC_FS/TT121%20Tall%20fescue%20microclover%20lawns.pdf

https://plantscience.psu.edu/reduce-runoff/questions-about-microclover

White clover, Trifolium repens, is hardy to USDA Hardiness zone 3..  Microclover is a small-leafed variety of white clover called ‘Pirouette’ or ‘Pipolina’. Overseed in spring or fall in the sunny parts of your lawn. It may not do well in part to full shade, according to some studies. 

Pros: It blends well with cool season lawns. Clover fixes nitrogen, and so reduces the amount of nitrogen fertilizer you need to apply for the grass. If allowed to flower, it provides an important food source for bees and other pollinators. 

Cons: It will be killed by common lawn broadleaf weed killers. And it goes dormant and the tops die back in winter, but it resprouts from the crowns in spring. It is not tolerant of heavy foot traffic. It prefers full sun and will dieout in too shady areas.  The ‘cons’ are why it is recommended to mix clover with a grass lawn, rather than trying to grow 100% clover as a lawn. Here are a few links to articles, with some details on pros-cons, and seeding rates.

MSU Extension is not permitted to recommend retailers or brand names. Use the scientific name given above to search for seed sources online, and check with farm supply type stores. We do have a nice article that discusses turf seed, and these principles can be applied when shopping for clover aeed:

https://www.canr.msu.edu/resources/purchasing_quality_turfgrass_seed_read_the_label

Thanks for using our service.