Is There Such a Thing as a Good Weed?

We all curse weeds in the garden, but what is a weed and can it ever be a good thing? I define a weed as anything that's growing where I don't want it. The offspring of one season's prized tomatoes can be next spring's weeds! However, when we talk weeds, most of us mean common invaders like bindweed (Convolvulus arvensis), chickweed (Stellaria media), and other plants we fight every garden season.

What good could come of a common weed? Some weeds with taproots like dandelion (Taraxacum officinale) break up compacted soil. The deep rhizomes of horsetail (Equisetum telmateia) help bring nutrients up from deep in the soil. A winter cover crop is nice, but even weeds are better than bare soil. They help prevent erosion and trap nutrients that would otherwise leach from the soil.

Most over-wintering weeds begin blooming sooner than other plants, providing an early food source for foraging insects like honey bees (Apis mellifera). Any leafy plants left growing in the garden provide a home for beneficial insects like ladybugs (Coccinella sp.) and spider-like daddy longlegs (Leiobunum sp.) On the other hand, I invariably find cutworms (larvae of most moths in the Noctuidae family) hiding among the weeds in my plot. Larger weeds like the Himalayan blackberry (Rubus procerus) provide cover and food for birds and other small animals.

When chatting about weeds, the question "What's the name of this weed?" always arises. Here are a few descriptions of the most common weeds in my garden. (Click on the linked scientific name to see photos to help you recognize these common weeds).

• Bindweed (Convolvulus arvensis): That white morning glory's real identity!


• Chickweed (Stellaria media): Light green mass of tiny leaves that slowly invades your plot over the winter and leaps to life in the spring.


• Henbit (Lamium purpureum): Square stems look suspiciously like its invasive cousin, mint.


• Poison hemlock (Conium maculatum): The feathery leaves of this biennial are deceivingly beautiful, but treat this dangerous plant with care. Wear gloves and a long sleeve shirt when pulling it. Bag it and throw it away with your household green waste.


• Quackgrass (Elytrigia repens): This pesky grass grows from aggressive rhizomes. Each joint in the root can sprout a whole new infestation! Dig this weed and let it dry thoroughly or hot compost it before digging it back into your soil.


• Shepherdspurse (Capsella bursa-pastoris): This starts out looking a bit like a small dandelion, but I think the small flat seeds look like hot pepper at the pizza restaurant.


• Shotweed (Cardamine hirsute): These seeds shoot all over the place the moment you touch it.

With the exception of poison hemlock and quackgrass, you should simply pull your weeds before they go to seed and bury them 8 inches or deeper in your garden. That's too deep to re-sprout, and they will contribute to the organic content of your soil.

Copyright © 2006 Brian Ballard. All rights reserved.

Compost Q&A

Here are some compost questions from astute readers.

Q. What do we do with garden waste that isn't applicable for chopping up and putting back in the garden, like sticks, raspberry shoots, noxious weeds and the like?

A. Believe it or not, you can put most any plant material in a hot compost pile! Temperatures in piles I've described here can reach as high as 160 degrees F. That's enough to kill most bad bugs, weed seeds, and pesky roots. However, our reader is right: some stuff just should not be put back in the garden, especially plants suffering from viral infections. Bag infected plants and throw them away with your regular household trash. Any old wood (like stakes or raised bed boards) should also be thrown away as they'll simply take too long to compost.

Q. Are there 'manual' options to using a chipper/shredder? It would be nice to know if one could get garden waste and "browns" ground up nice and fine like the shredder does, without messing with a machine. Manual chopping doesn't really do the trick.

A. Mercifully, it's not necessary to chop everything super-finely for compost. If you can get your plant material chopped to about 3" sections or shorter, and bruise the tougher stuff, then enough critters and fungi will get access to break down the material. I like to step on sunflower or corn stalk sections, partially rotten onions or garlic, and tomatoes or other fruit to bruise or crush them first.

Q: I have been chipping away at a stump in our backyard and would like to know if I can incorporate this wood in my soil or worm bin?

A: Though the individual chips might be too large for a worm bin, you can certainly use the chips as mulch on top of the soil, or incorporate them into your soil. A few chips in the soil are fine by themselves, but if you add a lot of chips all at once, they will steal nitrogen from the soil as they break down. In that case, add some composted manure at the same time to provide extra nitrogen.

If you want to add the chips to compost, treat them as a brown and balance them with greens (lawn clippings, vegetable food scraps, coffee grounds, tea leaves, etc.) Be sure the chips are pretty small (about 1" across). Otherwise they'll take too long to break down.

Q: I am building leaf mold and have a variety of leaf types in bags. Are there any particular leaves that are not good for creating leaf molds?

A: Leaf mold is essentially slow compost made of just leaves. It's used in similar ways to compost, and also for starting seedlings.

Most leaves are fine for creating leaf mold. It's better if you can chop them with a mower or leaf shredder first, but starting with them whole is OK too.

You might want to exclude pine needles or large, waxy leaves like those from magnolias, hollies or rhodies simply because they take too long to break down. If you want to include these types of leaves, definitely chop them first.

Some gardeners are suspicious that leaves from certain tress will harm their compost or leaf mold. I couldn't find any definitive studies to back that up. The primary theory seems to be that, after enough decomposition, any natural poisons are broken down enough not to be a problem.

Here's some more info on making leaf mold: Leaf Mold FAQ at GardenWeb.

Copyright © 2003 Brian Ballard. All rights reserved.

Common Compost Problems

Here are some common composting problems and how to solve them. Don't worry - you can't do any permanent damage to your compost!

Pile Won't Heat Up

Once your compost reaches maturity, it won't heat up very much between turnings. But if you've just made a new batch and it doesn't heat up after a few days, there could be a few reasons.

You may have used too much brown material - in this case, add more greens like fresh grass clippings, used coffee grounds, or composted chicken or steer manure.

If your pile is too dry, add enough water as your turn it so it's as damp as a wrung-out sponge.

If your pile is too small, it won't have the critical mass needed to retain heat. Make your batches in one of the 3'x3'x3' wooden bins at Interbay.

Heat loss will be faster in the winter so you should cover your batch with several layers of burlap. The wooden sides on most bins at Interbay also help insulate your compost.

Larger Items Don't Break Down

Larger sticks and branches take a very long time to break down. Sometimes sticks interfere with your ability to turn the pile easily. If you can, use pruning shears or long-handled loppers to cut sticks into small sections. Otherwise, exclude large woody items from your mix.

Bugs!!!

Not all bugs in your compost are bad. Some bugs help break down large plant material so smaller critters can help with the decay process. Pillbugs (also known as roly polies) and sowbugs look like tiny armadillos and help chew up rotting material. Don't kill them. (Here's some trivia: The difference between sowbugs and pillbugs is that pillbugs roll up when frightened, but sowbugs can't roll up.)

Any big fat white grubs you might find in your compost are probably beneficial and should not be killed.

Fruit flies are attracted to, and breed in, exposed food scraps or fruit. Cover any food scraps or fruit with a layer of dirt or finished compost, or dig them deeper into pile so the flies can't reach them. Don't just throw them on top.

Though ants in your pile don't necessarily help or hurt the decomposition process, they probably signal that your pile is too dry. Add water to your pile as you turn it. The ants should be gone the next time you're ready to turn.

Slugs just love the moist, warm environment of a fresh compost pile. I often find them sticking to the burlap covering as I remove it to turn a batch. Pick out any slugs or put the burlap on the ground and squish the slugs.

Plants Sprouting

If you have rootstock or stems that seem to be sprouting in your pile, be sure to chop them to 3" sections or shorter. I have this problem mostly with mint roots. A hot pile should kill most rootstock.

If seeds are sprouting in your compost, be sure your pile has enough green material and moisture to heat up and kill seeds. Seeds usually sprout in slow, cold compost piles that take a long time to break down. Turn any seedlings under before they can set seed.

The Pile Smells Bad

There are a couple of reasons why your pile might stink. If it smells like ammonia or urine, you've got too much green material. (You're also losing valuable nitrogen!) This usually happens when you've added too many grass clippings. Add more brown material like fall leaves as you turn your pile.

If your compost smells like rotten eggs, then there are anaerobic bacteria in action producing hydrogen sulfide. Your pile needs more oxygen, and potentially less water. Turn your pile to introduce oxygen, and don't add any more water. Be sure to cover your bin with piece of plywood to prevent rain from soaking your compost.

Animal Pests

Bury food scraps or fruit under dirt or more compost to keep raccoons, rats and mice away. Covering your bin will also keep larger animals out. Rodents like to bed down in warm compost. Catch any rats or mice you can and drop them into a bucket of water to drown them. Don't set a mouse or rat free: they will multiply to dozens in a few months!

More Reading

Cures for Common Compost Questions at Organic Style

Composter Problems at Quinte Waste Solutions

Compost Problems at REAPS

Guide To Home Composting by Ann Costa at GAIAM

Backyard Composting Problems and Solutions from Washington County, Minnesota

Large C Shaped Grubs In Compost Pile at GardenWeb


Copyright © 2003 Brian Ballard. All rights reserved.