Hollow Crown Parsnip Growth Habits: For the straightest roots, use deep, sandy loams and peat soil. Direct seed heirloom Hollow Crown Parsnip seeds 1/2" deep, spaced about " apart. Later, thin to 2-3". Parsnips take about 3 weeks to germinate, and require moist soil prior to germination. In the fall, when the parsnips are mature, they can be left in the ground and harvested when needed. The longer they stay in the ground, and especially after a light frost, the sweeter their taste. Seed packets , Organic seeds , Garden seed kits , Heirloom seeds , Non-GMO seeds , Vegetable seeds , Flower seeds , Herb seeds , Seed starter kits , Bulk seeds , Fast-growing seeds , Seed planters , Annual seeds , Perennial seeds , Indoor seed kits , Seed catalog , Microgreen seeds , Wildflower seeds , Seed subscription box , Seed tray sets