Ground Anchors Screw in 15 Inch, 6 Pack Spiral Trampoline Anchors Stakes Heavy Duty, Swing Set Anchors Tent Stakes for Camping, Car Ports, Canopies, Sheds, Securing Animals

These things (though not this specific brand) work real well for anchoring my large kites to the ground. Here is a direct link to the Amazon page.https://www.amazon.com/dp/B0DPZZW3XR