Do this:
Here is the cage out of reinforcement wire:
the bottom has 6 inches of "pokey" wire that gets inserted into the ground...
works for me everytime
Good question!
I have used garden soil before to start seeds, and tried a half garden soil, half potting mix and both methods produced hard caking soil. And I also think I have pretty good garden soil.
This year, I went back to strictly potting mix for my seed starts and the results were...