watering too much or 2 little?

i have about 8 plants that are sitting in a mixture of happy frog and MG seedling mix.. and now that they are growing larger and larger, they are about 3 weeeks old all working on the 4th 5th node... and unlike a few weeks ago, these plants seem to be underwatered by the end of each day, yet i think to myself, that cant be, the soil is still dark, and feels moist, but the leaves of the plant are all droppy and sAd, and then i add water and within an hr or 2 they look happy and healthy again...

my question, Are these plants now that they are a few weeks old, are they removing a lot more water from the soil than they did when they were little seedlings, like a noticable amount, to the point of having watered 1 time a week to once every other day within 3-4 weeks grow time?

i just dont want it to be something else and before u know it im overwatering...

and will i really even need to add nutrients to a rich soil like happy frog?

i know often the best thing to do, is to do nothing at all... one of our presidents of the great past i believe made that genious statement.

got a picture? over watering and under watering look the same. feel the containers thats the best way to tell if they have 2 much water. sometimes il stick my finger super deep into the pot.avoid the roots by sticking to the outer rim.yes bigger plants need more water.personally i used fox farms soils 2 and i add botanicare nutes, i have not had any problems.