Direct sow parsnip seeds outdoors from April to May to produce quality roots with less risk of canker disease. Avoid sowing in cold or wet soils. Grow parsnips in a sunny position in stone-free, well prepared soil that has been deeply cultivated. Parsnips prefer a fertile, light, well drained soil, which has been manured for a previous crop.
Sow parsnip seeds thinly at a depth of 2cm ( 3/4in) in drills 30cm (12″) apart. Germination is slow and may take up to 28 days. When large enough to handle, thin out the seedlings within each row to 7cm (3in) apart or 10cm (4″) apart if larger roots are required.