Warts are caused by the Human Papilloma Virus (HPV) of which there are over 75+ types. They aare not plants, nor do they have roots or seeds and they do not grow down to bone. The term "seed wart" therefore is a misnomer. The black spots that folks take to be "seeds" are actually dried bits of blood from the capillaries that have gotten squeezed by the irregular growth of the wart. When a wart ison the bottom of the foot, it is a plantar wart.
Treatments are many and varied and none are 100% successful. Every doctor who treats warts has their own favorite method. We all have successes and failures.
For further information, you can see a podiatrist or dermatologist.