When to plant new lawn in Netherlands — spring or autumn?

In NL climate, best lawn-seeding windows are mid-April to mid-May AND early September. Early April can work if soil temp stays above 8C for a week — this year thats unlikely before the 15th. If you sow too early, germination is slow and birds eat the seed before it roots. For bulletproof results, lay kant-en-klaar gras rollen (rolled turf) instead — 4-8 EUR/m2, instant lawn, best laid March-May.