Yard Butler ISP-33 Sod Plugger

I really wanted this product to work. My lawn is set in mostly clay soil in Ohio. Lawn has been established for 9 years, but due to summer months with less rain the bad grasses take over. My father had plugged his lawn in Kentucky with zoysia - a heat tolerant grass that spreads nicely in the 60's. This worked nice but turns brown too early and greens up late. The Yard Butler Sod Plugger is designed to make a nice size square plug. These plugs would be great for removing the undesirable grasses and planting new grass or sod in their place. The only problem is after a rain in late April and the ground was moderately moist, this tool could not cut thru the lawn and produce a plug. This might work well for sandy or black soil types but not for clay based soils. I imagine in the 2 to 3 week period right after winter the soil would be moist and soft enough use to use this tool. The tool is relatively sturdy, but could use a design change to work in certain soils. If a step on bar was raised higher - so as to allow more force it might work. I had limited success with a tulip bulb planter, but the edges were not sharp enough to properly penetrate the soil.