Animals that browse and burrow

Rabbits like to clip the young and tender hollow green leaves as they emerge in the early spring. As the leaves grow and get larger, the rabbits tend to leave them alone, possibly because the onion flavor gets stronger and the leaves get tougher for them to chew.

Here in the state of Washington prairie voles can be quite a nuisanse. In 2024 I lost thousands of Egyptain Walking Onion bulbs to these voles. They like to tunnel underground and chew the bottom of the bulbs where the roots are attached (the basal plate). This part of the bulb must be very tastey. They will usually eat the entire basal plate which kills the plant. They will eat no other part of the onion plant. I have seen nice green, mature, topsetting plants just fall over - seemingly for no reason - only to find that during the night the prairie voles ate out the bottom of the bulbs. They usually eat an entire clump of onions - one clump at a time. Landscape fabric around your onion plants may be a good weed deterrent, but it invites prairie voles. The fabric creates excellent cover for them to travel under.

Mice can also cause damage to the onions by chewing on the bulbs. Having a cat or a dog that likes to roam in your Egyptian Walking Onion patch can really help deter these critters.
Read more about the Egyptian Walking Onion Guardians.

Fencing can also help to prevent rabbits, mice, and prairie voles from accessing the Egyptain Walking Onions. Rabbits can be kept out of the onion patch with wire mesh fencing about 2 feet high. Prairie voles and mice require 1/4" hardware cloth that is above and below the ground. The hardware cloth must be burried in the ground at least one foot deep, and it should extend above the ground at least one foot (2 feet would be better so it could keep rabbits out as well).

Insects

Grasshoppers arrive in summer and chew on the topset stalks of the Egyptian Walking Onions. Amazingly, the topsets themselves are untouched by the grasshoppers. When they chew the stalk, they usually only chew it near the top about 2 or 3 inches below the topset cluser, and only on one side until the stalk bends over. This does not harm the topsets because they are still attached by half the stalk. Even though the stalk is bent, it can still keep the topsets alive. I have not observed the grasshoppers eating the Egyptian Walking Onion leaves, or topsets - only the stalk, and only half of it!

Thrips, onion maggots, and bulb mites are common onion pests, but I have not observed them on any of my Egyptian Walking Onions. If you do run across these pests on your onions, treat with neem oil. Crop rotation and keeping the soil surface dry and clean helps too.

Grass and weeds

Fast-growing grasses and broadleaf weeds will compete with your onions for light, water, and nutrients. Keeping your Egyptian Walking Onion patch weed free is crucial to enable nice, big, healthy plants to grow. Weeds also create inviting habitat for prairie voles by providing cover. After years of trial and error, I have discovered some strategies to keeping my organic onion gardens weed free. Some of which are: location, initial garden preparation, and mulch. Read more about maintaining your Egyptian Walking Onion garden.

Standing water

Onions don't like their feet wet. They can withstand short spurts of standing water, but not for very long. Standing water causes the bulbs to rot. This can be remedied with good drainage, raised beds, or gently sloping ground. In 2025 I lost hundreds of Egyptian Walking Onion bulbs to a flood. Standing water remained over the onion patch for a couple months.

Fungal visitors of damp seasons

In cool, wet, or humid weather, leaf diseases such as rust, blotches, and mildews may appear as spots, pustules, or soft, dusty growth on the foliage. These spread most readily when air is still and leaves remain wet for long periods. Sun, spacing, and removing affected leaves usually keep these troubles in check. Keep your onion patch weed free to allow air flow, and let the onions dry out in late summer as the topsets are ripening.

Balance in the onion patch

Every garden is a small world of pursuit and protection. Where pests gather, so do those that hunt them: birds, beneficial insects, soil life, and larger predators. The onions themselves, with their strong scent and hardy nature, often discourage more trouble than they invite.