Leek seeds are one of the more complicated vegetable seed varieties to plant and need different levels of attention at different stages in their growth period. Quite often, you will begin by planting your leek seeds in containers and then moving them outside and re-planting them into the ground once they have established. When following the correct process, leeks are easy growers. Leeks take a while to grow fully, and a March planting will typically result in a winter harvesting. The end result is delicious leeks that can be used in a wide range of ways when cooking up your next treat.