The best time to seed is late summer through mid October. The second best time to seed is March through early April. https://extension.umd.edu/hgic/topics/seedingsodding-lawns
Did you know that at one-time clover was part of home lawn seed mixtures. It is also a pollen source for pollinators especially early in the season when not much else is blooming. There is now a growing interest in what is referred to as 'bee lawns'.
It is an unrealistic expectation to totally rid your lawn of clover using either conventional or organic herbicides.
Clover is tough to control and you may want to aim in limiting spread. You also need to take a look at conditions that favor growth of this weed. Here is our website on clover https://extension.umd.edu/hgic/topics/clover
Here is more information on lawn weed control in Montgomery County.
Replies to lawn weed control questions from people in Montgomery now need to allow for the Montgomery County Pesticide Law. The Court of Special Appeals of Maryland recently ruled in favor of the law restricting the use of pesticides on private lawns and childcare facility grounds in Montgomery County. This is a new law and Montgomery County officials are still deciding on how to proceed. The Montgomery County Department of Environmental Protection has information about the law and organic lawn care on their website
We also have some resources on our website that may be of help to you:
Organic lawn care - https://extension.umd.edu/hgic/topics/organic-lawn-careTips for Lawn Weed Prevention and Management -