Picking varieties for a 2°C warmer growing window

Across Southern and Central Europe, the frost-free window has lengthened by 10-21 days since 1990.

But peak summer heat now triggers bolting in spring lettuces three weeks earlier than the seed packets suggest.

Swap Romaine for Jericho, Black-Seeded Simpson for Muir, and stagger sowings every 14 days from week 8.