New gardeners can be forgiven for thinking that weeds are unwelcome garden guests invited by nature to drive them crazy. Not quite: nature abhors a vacuum and has an arsenal of opportunistic plants that colonize open soil very quickly. Tough and fast-growing, weeds can easily out-compete desirable plants if you don't take firm control.
How to outsmart weeds
1 Know your enemy
The first step is to distinguish the weeds from the garden plants (for photos of some common weeds, check out www.omafra.gov.on.ca/english/crops/facts/ontweeds/weedgal.htm). This can be a challenge, as both may look alike to the novice. However, in spring, weeds tend to grow and green up before many perennials even get started, and most produce tiny flowers that bloom and go to seed quickly. Weedy plants also tend to have a somewhat acrid odour, so breaking off a piece of stem and sniffing it may give you a clue.
2 Turf the turf
Do a thorough job of getting rid of lawn or turf grasses and perennial weeds before you plant. Never just rototill an area then plant directly into it because grass and perennial weeds can regrow from small pieces of root or stem left in the ground. It's best to turn over the soil with a digging fork, breaking up any clods and removing any roots you find. As a last resort, gentle herbicides such as Roundup can be used, carefully following package directions (more than one treatment may be required). A non-chemical way to kill off weeds and grass is to cover the ground with commercially available black plastic, but this can take up to a year to be effective.
3 Observe the land
When you see a weed, remove it immediately. When small, they're easier to pull up or hoe out. Less tugging will be required if the soil is moist. Don't allow weeds to go to seed and multiply, and don't compost them.
4 Mow with care
Be sure to mow away from your garden beds -- lawn clippings may contain weed seeds.
5 Muchos mulch
To suppress weeds once you've planted, layer about 7.5 centimetres of mulch over bare soil between plants. Commonly available mulches include straw (not hay-too many weed seeds), cocoa bean hulls and shredded cedar bark. Basically, mulch keeps weeds down by blocking out the light they need to germinate.