Sarah Raven's tips for success

Work the area of soil until it is crumbly; wet soil with clods of clay is death to a fine seed like a cornflower. If your soil is heavy, work in some grit. Some well-rotted manure or garden compost will give the seeds a great start.

Sow in blocks or rows, never free-style; then you'll know which are seedlings and which are weedlings and need to be removed. To sow in rows, mark out with string or fine silver sand, poured from a bottle. To sow in blocks, sow in a noughts-and-crosses grid, using silver sand to mark your lines. Drag the handle of a rake or trowel along the row to make a shallow drill; sow seed at a depth related to the size of the seed.

To speed up germination, water the trench before sowing and avoid watering afterward, as this will displace the seeds. Sow them as thinly as you can and replace the soil by hand, patting it down firmly all the way along the row.

If there is no rain, water twice a week; not just a quick sprinkle, but wet the ground to a depth of several inches. After a couple of weeks, the roots will have reached the ground water in moist soils, so don't water unless there is prolonged drought.

Keep the seedlings free of weeds, which will compete for light, food and water.

When the seedlings are about 2.5cm tall and have at least two pairs of leaves, thin them out. Be brutal: leave one good plant every 10cm, and chuck the rest.

When the seedlings have formed tiny plants, transplant some to create the right final spacing, indicated on the packet. When they reach about 30cm, give them support.