Spring Weed and Crabgrass Control

dandelions in a field

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Lawn weeds are a persistent problem for homeowners. Weeds find their way into your yard in many ways. Wind, birds, your lawnmower, and even your feet can bring weed seeds to your lawn. The soil itself contains weed seeds, many of which remain viable for over 50 years. The question isn’t "if" you’ll have weeds to deal with, but rather "when" weeds will appear. These tips will give you a great head start on the weeds so you can spend more time enjoying the lawn.

Top Spring Weeds 

Here are 3 of the most prevalent and pernicious weeds that appear in the spring:

  • Crabgrass gets its name from the leaves, which form a tight, crab-like circle. This annual weed tends to appear in weak or bare areas of a lawn. Both over- and under-watering favor its growth, as does consistently mowing the lawn too short. Treat crabgrass in the spring with a pre-emergence herbicide to keep seeds from sprouting. Timing is tricky. In regions with forsythia, aim to get the herbicide down as the forsythia starts to bloom. While the flowering of forsythia is a good cue, crabgrass germination actually occurs after the soil temperature has reached 55 F for several consecutive days. Check with your local extension office or a reputable garden center to fine-tune timing in your region.
  • Dandelions are familiar in spring and fall lawns. These perennial weeds grow long taproots. The best control is to dig them by hand, but be sure to get at least 2 inches of the taproot or the root will re-sprout, yielding two plants. A thick, healthy lawn is your best defense against this weed’s wind-borne seeds taking root. Spot-spray dandelions with a post-emergence herbicide that doesn’t kill the grass. If you can’t treat plants, at least gather blooms before they set seed.
  • White or Dutch clover used to be a common ingredient in lawn seed blends. Now, this perennial is regarded as a weed. It tends to grow where the soil is poor and low in nitrogen. Hand dig small patches and apply fertilizer to those areas. Many times, bringing up soil fertility can help eradicate white clover. Apply a broadleaf herbicide according to label instructions. You’ll typically need to make several seasonal applications in both spring and fall to eradicate this weed.

When Spring Weed Control Begins

Timing is everything when it comes to spring weed control. As mentioned previously, the blooming of forsythia will approximate the time to apply a pre-emergent herbicide.

Pre-Emergent Herbicides

A pre-emergent herbicide is a weed killer applied prior to the emergence of the weed from the soil.

Chemicals like dithiopyr (Dimension) and pendimethalin (Lesco's Pre-M, Scotts' Halts) prevent all seeds from germinating, including grass seed. You should be aware that grass seed cannot be applied for 6-12 weeks after application, depending on the specific product.

The chemical siduron (Tupersan) prevents only weed seeds from starting, allowing grass seeds to germinate. However, it is costlier and best used sparingly.

Corn gluten meal is an organic alternative initially used as feed on hog farms but discovered to have pre-emergent characteristics.