Is there a DIY solution for getting rid of crabgrass?

This process takes a few days, but is what is recommended now instead of Roundup. The first week or so it will slowly wither and by the 10th day it should be dead. It won't hurt your lawn unless you get anxious and apply more coats. Just spray ONE time and wait. Use Tenacity. Some people add 3 tsp Surfactant to help it stick to the plant, and some use 4 tsp of Lazer dye so they can tell where they have sprayed. It may take up to 3 weeks to completely kill the crabgrass so be patient.

Pull it or spray with vinegar or this solution (note, any spray will also kill other plants and grasses):

2 cups white vinegar

¼ cup salt

Squirt of dawn

Mix in a spray bottle. If you have a larger area, you can mix in a garden sprayer with larger quantities. Use when it will not be raining for a few hours so that it isn’t washed away.

Preen lawn crabgrass control

Spectracide Weed and Feed in the hose end sprayer. No mixing no mess. Will kill weeds and crabgrass, feeds the lawn. A thicker lawn leaves no room for weeds.

Hello Chemical Prevention/Treatment in Lawns points Listed below might be helpful.

https://extension.umd.edu/hgic/topics/lawn-herbicides

• Herbicides should be used as a last resort because of the potential risks to people, animals, and the environment. Be aware of these precautions first.
• Use a granular (apply with a spreader), selective, preemergent herbicide. Apply a preemergent without nitrogen fertilizer. Look for the active ingredient: Prodiamine (Barricade) or other preemergents labeled for crabgrass control. Apply in early spring (March) before it germinates. It germinates earlier than crabgrass so to prevent J. stiltgrass the preemergent needs to be applied a couple of weeks earlier than for crabgrass prevention.
• Rainfall or irrigation is required to dissolve the herbicide which is then absorbed into the upper portion of the soil and forms a barrier which kills weed seedlings. Preemergent grass herbicides have residual activity that lasts for several weeks after application. High temperatures and rainfall will decrease the length of time they remain at sufficient concentration to be effective.