The cleanest and safest water you are going to find, at almost no cost, is the stuff coming out of your faucet. If you are worried about the chlorine, which you shouldn't be, then all you've got to do is fill up a barrel or tub or something similar and let the water sit uncovered for a while. The chlorine in the water will dissipate on it's own. If you want to dissipate it quicker, buy an air pump that's sold at pet stores for aquariums and have it aerate/agitate the water. Or if you don't want to wait to use the water, they sell stuff at pet stores that's used to treat tap water to remove chlorine and heavy metals before refilling a fish tank. (Examples in the link below.) The chemicals are safe for fish so draw your own conclusions. I'm with loribee2. If you are going to stress over all these miniscule things (and I'm not saying this to be mean or anything) then maybe you shouldn't be gardening. There are times when gardening IS stressful. Pests, disease, fungus, critters, weather, nutrient deficiencies, etc. But the things you are talking about... they just aren't worth stressing over. Rodney Here is a link that might be useful: Chlorine & Heavy Metal Removers

In North Carolina, we can get soil tests done for free from NC State (an ag school). We also get instructions from our local ag agents both from classes or publications. Timing doesn't seem to matter. I believe commercial growers are still interested in new results and could be in situations similar to yours where supplies have already been added. So you could certainly send off a well mixed sample of your fertilized soil. However, if it were me (only doing one test), I think I would want to know what my native soil would be needing and I would dig up several undisturbed chunks of soil away from your garden (and each other) and send a mix of that. The report will probably tell you what to add and MAY also tell you what to add in subsequent years for maintanance.

I wouldn't do anything to try to treat for iron unless you have chlorosis. Adding iron isn't likely to help, because the issue isn't a lack of iron, but an inability of plants to use the iron that is there. As Bill noted, grass will probably not have a problem using the iron. If you have plants that have problems, you can deal with those plants, and you'll have much better success that way. Spreading sulfur won't help much. It needs to be under the soil or too much of it is lost to offgassing. If you've got chlorotic plants, sprayinh the leaves with water soluble iron will providfe a quick greenup, but there's a thin line between spraying enough to help and spraying too much and burning. Once it's hot out, spraying any will likely burn the leaves. Also, spraying in liquid form is very short lived. To provide a longer effect, drill holes with a bulb augur add soil sulfur and cover with dirt. Adding organic matter as often as possible will also help. The sulfur takes longer to help, but it's longer lived. In between those is adding chelated iron. With a 7.8 pH, EDTA iron chelate will probably not help, and you'll need to use EDDHA to get good results. Unfortunately, EDHA is more expensive and not as easy to find as EDTA. You should also water deeply and let the soil dry before watering again. For trees, about once a month, water around the drip line very deeply. I set the hose in several spots around the tree and let it run on a trickle for a half hour or so. I think the amount you want to provide is 5 gallons of water per inch of trunk diameter (once a month).

All of the science is over my head, but I know that a 30-ft pecan tree would be considered a youngster here for about any variety. Pecans are known for producing in cycles, with 1-3 light years between heavier harvests. I've lived under a giant pecan tree for 5 years (forget which kind, but it's the one with the biggest, oval nuts) and have witnessed 2 "nice" harvests. We don't do anything in regard to fertilization, so no ideas on that. Pecans make juglone, albeit in much smaller amounts than the famous walnut, it is there for consideration, especially in regard to super-sensitive plants like tomato (and so many other veggies!) My limited understanding of the effect of growing veggies in the proximity of a pecan has led me to believe the juglone is more prevalent in the leaves, nuts and hulls that are dropped than in the soil from the roots. Different varieties contain different amounts in the various parts. Taking this into consideration in your placement of certain plants might help.