Living Columns & Blogs

Ask a Gardener: Nitrogen helps compost destroy fly larvae

Rich, loamy compost is a gardener’s gold. Turning weekly and adding nitrogen allow compost to heat up to destroy fly larvae.
Rich, loamy compost is a gardener’s gold. Turning weekly and adding nitrogen allow compost to heat up to destroy fly larvae. Tribune News Service

Question: Ick! There are a lot of fly larvae in my compost. What’s wrong, and can I get rid of them?

Answer: Of course you can. A well-managed compost is a delight and won’t result in fly larvae. In your case, it’s a simple matter of your compost not heating up enough.

Without aeration, compost does not heat up fast enough to discourage flies from laying their eggs. Turn the pile once a week and it should stay hot. If it still doesn’t heat up, you might need to add more nitrogen, in the form of fresh manure or grass clippings. Make sure the compost is moist, but not soaking wet, like a wrung-out sponge. And if it’s still raining from time to time, cover it with plastic to keep it from getting too wet.

Master Gardeners of Whatcom County conducts free workshops on composting and has a wealth of information on composting. You might find some of this useful. And good luck. Rich, loamy compost is a gardener’s gold.

Q: My children think the little sow bugs they find in the garden are cute, but I wonder if they aren’t a pest. I have gazillions in my gardens. Can you tell me something about them?

A: Cute, yes, particularly when they roll up in a defensive ball. Which they’d better do when I’m out to get them.

Yes, these darlings favor young, succulent growth and so can be a scourge, particularly in a newly planted garden or early in the season.

They prefer damp, cool hiding places, and you often can find legions of them under boards and stones, and in mulch and manure. Females retain the eggs in a body pouch until after the young hatch, 25-75 at a time. Ouch.

Fight these voracious pests in two ways. First, practice good sanitation. Keep your gardens and outdoors clean of anything that can provide the damp and cool hiding places sow bugs love. The drier the better.

Then, after you’ve cleared all potential sow bug hiding spots, set your traps. And that’s as simple as a rolled up sheet of newspaper or corrugated cardboard. The sow bugs crawl into these at night, for shelter. In the morning, simply dispose of the shelters, sow bugs and all. Do this for several nights and you can make good inroads into your sow bug problem.

A welcome garden sight

Those of us who have gardened for a number of years know that often while you’re out in the garden you’re witness to the most amazing natural phenomenon that you would completely miss were you not on your hands and knees in the dirt.

While weeding around a plant recently, I came face to face with an unexpected and unusual sight: a wasp had landed on the plant and was eating the remains of a tent caterpillar I had squashed moments before. Though I’ve heard for years that wasps do eat insects, seeing this one in action made my day. Though not in the numbers as last year, those blasted caterpillars still are doing damage. Go wasp!

Update: In my description of making rhubarb juice to control aphid infestations, a reader wasn’t clear what I meant by “stems.” I meant you chop up and boil whole stems, including the leaves, which contain the oxalic acid necessary to kill aphids. I’d be interested to hear if anyone has used this remedy and what the outcome was.

Kathleen Bander of Bellingham is a life-long gardener. Her column will appear in The Bellingham Herald weekly through the summer growing season. If you have a gardening question you'd like answered in the column, please email it to For more gardening information online, go to