Keep in mind, with corn being used as fuel for vehicles, corn gluten meal is rising in cost. Shop for the best price.
If you have waited too long and the crabgrass begins growing, preemergents usually have no effect. However, there is one product with the trade name “Dimension” (Chemical name: dithiopyr) that will give some control of seedling plants for a few weeks after emerging from the soil.
It develops from a fibrous root system and has a prostrate to upright growth habit. With mature plants, it is common to see the stems branching out at the base, remain prostrate for an inch or two and then curve upward at a 30 to 70 degree angle. Each plant can produce multiple stems that can easily grow twice the height of the leaves.
Cultural Practices that Help Prevent Grassy Weeds
One main difference between chemical preemergents and corn gluten meal is the amount applied. Corn gluten meal must be applied between 10 to 30 lbs 1000/sq.ft. Generally, 20 lbs/1000 sq. ft. is the average for most lawns. Use more for severe weed problems. It does not require a license to use.
A preemergent must be applied before the crabgrass seeds germinate in spring. Again, it MUST be applied before they germinate with only one exception, the use of Dimension preemergent will kill the crabgrass at very early seedling stages. I will describe this in better detail below.
If crabgrass is a problem, avoid fertilizing in late spring and summer. Especially avoid applications of high Phosphorus fertilizers. Phosphorus is essential for seedling growth and will only promote crabgrass establishment.
Control: Mulch garden areas in spring to prevent weeds. Pull oxalis weeds by hand or spray weeds with a postemergence herbicide in spring or fall.
A weed can be any plant growing where you don’t want it to, but there are some particularly weedy species to keep an eye out for. These aggressive plants choke out the garden plants you’ve worked so hard to grow. Use this handy guide to identify weeds by photo and know how to best remove them.
Where It Grows: Sunny or shady landscape, lawn, or garden areas
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Appearance: This garden weed has light green leaves that look like clover and cup-shape yellow flowers in summer and fall.
Lawn Weed Control Tip: Mulch to prevent dandelions in gardens. Pull dandelion weeds by hand or use a postemergence herbicide (designed for using on weeds after they appear) in lawns.
Size: 12 inches tall, 6 – 16 inches wide
Where It Grows: Lawns and gardens in sun or shade