depends on pot size and plant size, mostly.
i'd start with a 1:2 ratio to start. don't mix a full gallon if you don't want it sitting around long. mix 1/2 gallon with 1/2 of instructed amounts... it'll be the same exact thing.
so, fertilize, 2 irrigation, fertilize etc.. If this plant is still young, hold off. If you are in FF soil, hold off even longer -- seeds are packed for 2 week and FFOF, for example, is a hot soil that will keep you going 4-8 weeks without fertilizer.
don't jump the gun. .first time i'd wait for a slow down of growth or any hint of yellow in leaves (excluding cotyledons - the two tiny initial leaves with no serration). And then, start with 1/2 strength of instructiosn.. maybe, 1/4th for FF nutrients... then 1/2 would be your normal feed after that...
always easier to increase feed... tough to stamp out a toxicity... so don't create one..
feed a little more, observe for a week or so how it reacts... any sign of darkness or burned tips, you need to back off.