As a substitute for in-person programming, we’re offering a series of posts on starting a vegetable garden. This science-based information comes from the Seed to Supper program, developed by the Oregon Food Bank. During these difficult times, the Oregon Food Bank welcomes your donations.
OSU is also offering its vegetable gardening class online.
Weeds are just plants growing in the wrong place, but they compete with your crops for sunlight, water, nutrients, and space. This can be a big problem, especially when crops are still young and small.
Weeds can also bring pests and diseases into your garden. Controlling weeds gives your plants a better chance to succeed. Weed seeds can stay alive for years and will come to the surface when you begin to work the soil. Removing weeds before they make seeds will save you time and work in the years to come.
The easiest way to control weeds is to stop them from getting started in the garden in the first place. Start with a well-prepared seedbed, which means getting rid of all weeds before you plant.
Organic mulches help control weeds and add compost to the soil as they break down. Materials like shredded leaves, straw, compost, and weighted-down cardboard or newspaper all work as mulch. (A few types of leaves, like walnuts, oaks and cottonwoods, can stunt the growth of crop plants. Avoid these in the garden.) Mulch keeps the soil loose, so weeds that do come up will be easier to pull. Add 2 to 3 inches of mulch to smother weeds.
When plants are as close together as they can be, their outer leaves touch and form an umbrella that shades out weeds. On the other hand, close spacing can make it harder to find weeds that do grow. When plants are spaced closely, you need to pull weeds by hand because hoeing could damage your crop.
Just like crops, weeds need water to germinate and grow. How you water can mean more weeds or fewer weeds. Drip irrigation, soaker hoses, and careful hand watering all put water close to your plants and leave unplanted soil dry. That means fewer weeds will grow.
Also, keep grass cut and get rid of any weeds growing near your vegetable garden. You do not want grasses to make seeds, which could drift into the garden. In addition, crop rotation can reduce weed problems. Group crops by family and rotate them into new sections of your garden every year.
Despite your best efforts, weeds are sometimes unavoidable. The best approach is to weed early and weed often. Young, tender weeds are easy to hoe, hand pull, or till in. Remove them during the heat of the day between watering. Don’t weed when the soil is wet, because working wet soil can damage the soil structure. And don’t leave weeds to grow, because bigger weeds are harder to get rid of.
If weeds have overtaken your garden, or if you do not have much time, focus on weeding in order of importance. First, dig up any weeds that are going to seed. Next, remove all grasses and invasive weeds, such as bindweed (morning glory). And finally, when you have the time, remove the other, less–invasive weeds.
Hand weeding and hoeing are the best choices for weeding in the home garden, because they allow you to weed close to base of veggies without damaging the roots. Small hand tools like the Korean hand plow are good for weeding small areas and between closely-spaced plants.
Another useful tool is the dandelion digger (also known as a weeder, cultivator, or asparagus knife). It works well for digging weeds with long taproots. If you don’t have a dandelion digger, use a screwdriver.
There are several different types of garden hoes. The lightweight Warren-type of hoe has a pointy tip and is useful for weeding between plants. The hula or action hoe is a lightweight scuffle hoe. You use it by pushing and pulling it just under the soil surface. It pulls up small weeds, but doesn’t work as well against bigger, older weeds.
Keep a rag where you store your hand tools so you can wipe off soil and moisture after using them.
Next up: Pest control