To start from scratch is to begin again with nothing prepared. Start from scratch, built from scratch.
The scratch was the line scratched in the ground at the start of a race, so it means the very beginning with no advantage. In cooking it means using raw ingredients rather than anything ready-made.
1phrasestart from scratchTo begin again with nothing prepared.
“The file was lost and they had to start from scratch.”
start from scratch is a phrase.
Practised in Idioms