Most "weeds" have soil preferences where they grow quite well and Ma NAture does not like her soil left exposed to the ravages of the sun, wind, and rain so she has arranged many ways for plants to get seeded in any bare soil spots there are. Knowing that then tells us that a good, healthy turf is a good way to control the growth of what we consider "weeds" (plants we do not want growing where we do not want them) and of course the first step in that process is a good, reliable soil test.
Since you live somewhere in the USA contact your state universities Cooperative Extension Service to find out about having a good, reliable soil test done so you know what your soils pH and nutrient load is, and what needs to be done to corect any problems. Also dig in with these simple soil tests,
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 your 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.
which can guide you in making a good, healthy soil that will grow a strong and healthy turf.
Iron is a micro nutrient necessary for good plant growth, but like many of those micro nutrients a little too much is a plant poison so you may want to rethink using that product.