Yes, it is perfectly normal for many perennials (especially slow-to-establish species like Baptisia) to look like they're not growing much in their first or second full year in the ground. The adage "first they sleep, then they creep, then they leap" generalizes a common pattern followed by new plantings, which is to say that they don't look like they're doing much the first year (though more root growth, out of sight, is occurring); the second year they increase in size a little; and the third year they really start coming into their own, with more growth and the beginning of flowering (if they weren't already). Not every species follows this pattern, but it is typical of many. Baptisia is notorious for looking fairly wimpy and unimpressive in terms of growth when sold in containers, but as they get established, they can be long-lived and very lush. They also do not tolerate being transplanted well, at least once roots are settled-in, so avoid moving them if possible, unless conditions like sunlight level and drainage are not suitable for their needs. Fortunately, they handle clay soil well, as long as it's not soggy or poorly-drained.

Incorporation of 3 inches of organic matter, plus the slow addition of more as mulches break down and are replenished, should be plenty for most plants.

We haven't tested the accuracy of moisture meter probes, so consider also testing the soil by hand at first, to see how consistent its readings are. Feeling the soil around four to six inches deep near the root zone of plants will help determine when watering is needed. If it feels somewhat dry to the touch at that depth, watering would probably be beneficial. If damp when checked, watering is probably not needed. You can do a simple percolation test if you want to see if the soil has adequate drainage or not by digging a hole, filling it with water and letting that drain, and then filling it a second time and timing how long that takes to drain. Details can be found on the linked page.

Miri