Because the stump was ground out, you had a lot of "browns" in the soil. Thus, the microbes used up the nitrogen before your veggies could get it.

All you need do is apply an extra bit of nitrogen to keep those microbes working even while the veggies grow. To do so, watch your plants closely to get a feel if they're doing fine or if beginning to lag. Then use a quick-release (readily soluble ) source of nitrogen as needed.

Start with a good, reliable soil test, find out what the soils pH is and what nutrients are there and what you might have to do to improve that soil. These simple soil tests can also help you determine what that soil is like now,
1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer you soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.
as well as what you need to do to make the soil into a good, healthy soil.

Here is a link that might be useful: USDA CES offices

Wow, that's a lot of good information, thanks so much! I don't know anything about gardening.

Since I have the blueberries already waiting to be planted (they were on sale), I think I'd better just start by adding nitrogen, plant them, then do the rest of the testing, which may take a few days to get to?

Personally, I'd do it the other way around. It is far easier to add amendments before planting than it is after the fact. And while all plants appreciate nitrogen, blueberries are not going to require as much as many leafy veggies. But they do have other rather specific soil requirements (acidic and moisture retentive) that are best addressed when you know exactly what the conditions are by testing. Just adding a bit of nitrogen may not be enough to satisfy their growing requirements.

Large trees that have been in place for many years tend to deplete ALL soil nutrients in the immediate area. Get a soil test done first, amend soil to add necessary nutrients as the test directs, then plant. Your blueberries will be fine waiting for a week or two before planting.

When sawdust or wood shavings are added to soil a couple of things happen. Certainly nitrogen depression is one of them. When the soil organisms are exposed to high amounts of carbon they sequester the available soil nitrogen as they increase their populations. In order to build cells they need nitrogen for protein synthesis. Until the woody material is broken down the soil structure is also altered. The technical term is hydrologic discontinuity. The ability of the amended soil to both store and move water is affected. The amended soils often appear droughty until the material breaks down. Because the soil and the wood product are dissimilar they tend to wet at different rates and the ability of water to move by capillary action is also disturbed. Following the decomposition of the woody material the soil structure should be enhanced. The questions of nutrient levels and pH can be answered by a soil test.

Okay, how does one "get a soil test?" I have no clue.

The link that is on the bottom of my first post will take you to a map of the USA and you find your state there and the link there will take you to contact information for your county office of your state universities USDA cooperative Extension Service. They will be able to tell you how to get a good, reliable soil test.