Do I topdress plants in March regardless of when last frost is due? Thanks.
If you read much about top dressing, there is lots of advice of when, sometimes fall (for cool season grass) sometimes spring (warm season grass.) Most often, spring is advised, so grass can get established before summer heat, but I don't think there's any hard rule about March. Do it when it's convenient. https://www.gardeningknowhow.com/lawn-care/lgen/top-dressing-lawns.htm