Thinly (sowing)

This is a vague term which is used ubiquitously. In general, if you place small seeds roughly 1.2 to 2.5cm (half an inch to an inch) apart then you won’t go far wrong. Larger seeds (such as peas) are placed further apart. If the germination rate is high and many seedlings are wasted by later thinning, just sow thinner next time!