Seeds the day
My pick for Spring seed sowing would be root vegetables like Japanese turnips, swedes, carrots, and parsnips.
There will also be time for planting seedlings of cauliflower, broccoli, spinach, leeks. celeriac, kohlrabi, and Florence fennel.
Carrots and parsnips can be sown directly into well-drained sandy soil. Make sure the soil is weed free, then rake, in preparation for making shallow seed rows into which you will sprinkle the seeds. Carrot seed is small, and it is hard to space the seeds out evenly, so once the seedlings come through you will need to thin them out.
Cover the seeds with bent wire frames and then old net curtains, frost cloth, or light green shade cloth. This will help with germination and also keep the birds off.
Parsnips also like a loose soil. The seed is slow to germinate, often taking three weeks.
Parsnip seeds also loses its viability very quickly, so I always let one of my plants go to seed and collect fresh seed for the Spring planting.
Sow swedes and turnips seeds directly into the garden. Prepare the soil as for carrots and cover as well. You will find these seeds are up in less than a week (depending on the warmth of the soil).
Space the plants by thinning out the seedlings that can be transplanted. The plants mature quickly, especially the Japanese turnip, which looks like a little golf ball and will be ready to eat in about five weeks. These white-flesh turnips are delicious raw or grated into salads along with kohlrabi, young swedes, celeriac, and beetroot.