In the bottom two middle squares of my raised bed garden, the spinach and leaf lettuce is growing from last month, but now it appears like there are some unwanted plants as well — weeds! In just a few short weeks, our garden has been overtaken by weeds. The weed seeds came from the topsoil I purchased. Weeds are a problem when you have a garden of any size, unless you use new, sterile, soilless growing media each season. Knowing what you planted will really be important so you can be on the lookout for the seedlings, and remove just the weeds.
Seedling leaves (cotyledons) often look completely different from the first true leaves that come out later. One characteristic that can help you in figuring out if you have a weed or a plant you want to grow is by looking at the number of leaves that sprout from the seed. If the plant has one seedling leaf, it is called a monocot (monocotyledon). This includes plants like onions, corn, and grasses. If the plant has two seedling leaves at germination, it is called a dicot (dicotyledons) and includes plants like tomatoes, beans, potatoes, spinach, and lettuce. Dicots are sometimes referred to as broadleaf plants. Many times selective herbicides work on either monocots or dicots but not both types of plants; that’s what determines which plant will be killed by the herbicide or which will be resistant. Non-selective herbicides will kill both monocot and dicot plants.
Sometimes people get really upset when I call a plant a “weed.” Please remember that many plants can be designated as weeds. The simple definition is “a plant growing where it is not wanted.” So even though weeds can have desirable characteristics, when it is a plant growing where it is not wanted, it is a weed. Weeds compete for sunshine, water, space, and nutrients in the garden, and some can be hosts for diseases and pests.
As with most gardening tasks, addressing the problem early and often is the best advice. Being able to identify weeds when they are small is one of the skills that I continue to hone each growing season and it takes practice and time. Knowing what you planted and where you planted it is the first step in knowing what may or may not be growing. Virginia Tech has a nice identification guide that lets you answer questions about the specimen and points you to a possible answer.
I will be using mechanical control methods (hand pulling or a small hand shovel to remove the weeds) because it’s such a small area.
In our commercial high tunnel operation, we use a physical barrier as our first line of defense in weed control. Wind can cause hardships with keeping landscape fabric held in place, but we use 6-8’’ long landscape pins to hold it down.
Here is information on managing weeds organically.
We have had some very chilly night temperatures which is not too uncommon here in the mountains. Our expected frost-free date is June 5th, so I’m looking forward to putting in some warm season vegetables in the coming weeks — tomatoes, peppers, green beans, and maybe a summer squash are on our list.
By Ashley Bodkins, Senior Agent Associate and Master Gardener Coordinator, Garrett County, Maryland, edited by Christa Carignan, Coordinator, Home & Garden Information Center, University of Maryland Extension. See more posts by Ashley and Christa.