Harvesting parsnip seeds. Since parsnip seed doesn't keep well from one year to the next, fresh seed is usually used each year to ensure germination. I let four or so parsnips we had left in the ground over the winter go to flower and then seed for planting next year, we eat the rest. The bees were nuts over the flowers when they were in bloom as they were bright yellow and besides my annuals, and other crops I let flower and go to seed, there was not much else in bloom at that time.  I do not plant a whole row of parsnips usually, we dig a couple up over the winter months and leave most of them in the ground until the spring when they are at their very sweetest.  We cook several chicken dinners on beds of parsnips and then I like to make a big pot of parsnip soup. I probably plant about twenty parsnips in all. They are surprisingly tasty and taste nothing like any parsnip I've ever bought in the grocery store.  Although I don't plant many, they are definitely a must-have in the winter/spring garden.