In your vegetable garden, mow green manures as soon as they encroach on space needed for main crops. With years of hands-on experience in organic gardening, I've found this timing maximizes soil benefits while minimizing competition.
Always mow green manures before they bolt to seed. Leave the clippings in place to dry, then bury them into the soil. For versatility, compost them or repurpose as mulch in other beds.
No deep tillage is required post-mowing if growth is short and residues are cleared—a simple soil scraping to aerate suffices. Crucially, leave the roots intact; their decomposition builds humus and delivers nitrogen riches from legumes like clover, alfalfa, and sainfoin.
Above all, never leave soil bare. Return what harvests remove through balanced inputs—organic matter, minerals, or natural fertilizers—to sustain long-term fertility.

Meadow red clover, Trifolium pratens