Herbs worth a greenhouse

A greenhouse changes which herbs are possible rather than merely easier — basil, Thai basil, lemongrass, curry leaf and Vietnamese coriander are the ones it unlocks, and a further group of soft annuals gains real weeks at either end. Set to include both, because for herbs the extension is genuinely worth the bench: an autumn sowing of chervil or coriander under cover crops when nothing outdoors will. What it excludes is the group most often put under glass by mistake — rosemary, sage, thyme and lavender, which are hardy, and which die of winter damp under cover far more often than they die of cold outside.