Whether you like your onions sweet or more tart, Burpee has a variety for you. While some onions from Burpee come as seeds, others are sets, which are simple to work with and a breeze to plant. Before you begin, you'll need to prepare your garden to plant Burpee onion sets. Once they are planted you'll just need to keep an eye on watering your onions to keep them growing.
Work the ground in spring to break up large clumps of soil once it thaws. Add well-rotted manure or compost to the bed to increase looseness as needed until the soil has a fluffy texture and look to it.
Make a shallow trench, or furrow, an inch deep and as long as necessary to hold all of the onions you want to plant. Create multiple rows 6 inches apart, or place your onions along the borders of your garden bed.
Place sets in the furrow, pointed end facing up, spacing each set 3 to 5 inches apart. Larger onion varieties will need the full 5 inches of space, while smaller onions, or onions grown for green onions, will only need 3 inches.
Press the sets into the soil just enough to firm them in place, then cover them lightly with soil from the edges of the furrow to fill in the trench.
Water the onions to moisten the soil and keep the soil relatively moist throughout the growing season, never letting the soil become overly dry or waterlogged for long periods of time.
Fertilize the onions with a liquid all-purpose fertilizer when leaves first start to appear to give them an extra boost.
Harvest green onions as needed by cutting stalks. For bulb onions, bend the stalks over without breaking them before the flowers open, and pull from the ground when the bulb has reached mature size and the stalks are dry.