The stony ground refered to here is a thin layer of soil upon a stone, in which when seed is planted it will germinate quickly, but because of the shallowness of the soil and the rock beneath there can be no depth of root. It is well for a plant that has shallow roots so long as there is regular rain and mild conditions, but when droughts come and high temperatures prevail, the plant will wither and die. Just like the stony ground we may appear well on the surface, while beneath lies a heart so hardened the word can find no place to root and by and by we will pine away spiritually.