I had to dig a hole last year at this time. The frost line was about 10" deep, and after that the digging got easier. If you get a spade shovel with a flat top, you can use your feet to help with the digging. Carefully put your foot on top of the flat part and push with the foot as well as the shoulders. Worked for me. You'll sweat, pant and puff, but it can be done. If necessary, use a garden hoe to start. Just take your time and don't overexert yourself.