Will the addition of fertilizer to soil increase plant growth?

Fertilizer does not affect plant growth that much, and trust me i know because i had to do this for an experiment and i had three cups: #1 was planted with plain dirt and was watered (without fertilizer)every other day #2 was planted with plant soil and was watered (without fertilizer)every other day #3 was planted with soil and was watered with fertilizer every other day and my plants were radishes and on the packet it said it would grow from 4-6 days and plant #2 was the first to sprout then #1 and then #3 which was a shock because it took plant #3 about a week or more to sprout even though i added fertilizer