How do I keep premium mint supplying year round and stop it dying back in winter or summer?

Premium culinary mint buyers (bars, hotels) want leaf every week all year, but open-field mint slows in cold winters and suffers in peak summer heat, so continuity takes planning. Mint grows from runners and spreads fast, so propagation is easy; the challenge is steady tender leaf. To keep year-round supply: stagger plantings and keep several beds at different growth stages so you always have fresh flush to cut; in peak summer give partial shade and steady moisture to stop scorching and small tough leaf; in cold areas, mint may die back, so protected cultivation (net house or polyhouse) or growing in beds you can shelter keeps it producing through winter. Keep cutting and pinch off flowers, because flowering makes leaves small and tough and breaks your grade. Refresh beds periodically by replanting clean runners, since old mint beds get crowded, rust-prone and woody. Maintain good nutrition and moisture for large soft leaves. Because supply continuity is what keeps a bar buyer loyal, only commit to a standing order you can actually meet year round, and if your climate has harsh extremes, plan protected cultivation from the start. Agree the standing weekly quantity and grade with your buyer in writing.