If Hayden had 2 1/2 gallons of water the seed packet said to use 1/4 for peppers and 5/8 for tomatoes then used some for lettuce if Hayden has used 3/4 gallon of wate about how much did he use for the lettuce

you say: If Hayden had 2 1/2 gallons of water ...

then you say: if Hayden has used 3/4 gallon of water
so, which is it?