Reading the sowing calendar on the packet

The months printed on each packet are a guide to when the seed will germinate reliably in an average British garden. They are not a rule.

Sowing early

If you have a heated propagator or a warm windowsill you can usually start a month ahead of the earliest month shown. The risk is not germination but what happens next: seedlings that outgrow their light.

Sowing late

Many hardy annuals sown in autumn will overwinter as small plants and flower a good three weeks earlier than a spring sowing, on sturdier stems.