Weeds in the Onion Garden

Problems With Weeds

• Some weeds harbor insect pests that damage onions. If an entire area of your garden is devoted to growing onions alone, this means that once the insects are attracted by your onions and harbored in the neighboring weeds, they can easily spread throughout the garden, chewing up your onions or sucking them dry and transmitting diseases in the process.

Reducing Weeds

• Mulch helps suppress weeds and conserves moisture: two critical roles in the onion garden. Setting out transplants that have been grown in weed-free seed trays means the onions are off to a good start, and you don't have to leave the soil in the garden open to weed invasion while you wait for onions to germinate. Heavy mulching combined with hand-pulling weeds takes care of most weed problems.

Replacing Weeds

• While onions aren't very good at competing with weeds, other herbs, vegetables and flowers might be excellent at it. If onions are surrounded by other garden plants that shade out weeds, but aren't tall enough to shade out onion transplants, onions have a better chance of getting the water and nutrients they need. Plants that harbor insects that prey on the pests of onion plants are an even greater boon, because they also serve as a kind of pest repellent or pesticide for the onion garden.

Considerations

• Many predatory bugs, such as green lacewings and ladybugs, eat thrips by the truckload. However, these predatory bugs also feed on nectar, so planting flowering plants and herbs near onions will help convince them to stick around while simultaneously helping to suppress weeds. Onion flies are harder to combat, so nematodes are often sold as biological deterrents. However, even these microscopic creatures need an inviting environment, and mulched, rich soil plays host to many creatures that the nematodes can live on over time, waiting for the next season of onions and possible onion fly pests that may come through.