Could too much fertilizer or overwatering one or two times have caused the yellowing leaves?  I have used SuperThrive and also MiracleGro fertilizers.

Also, what is the best product to feed these young trees?  Is feeding them the same as fertilizing? 

The white powder on the leaves is diatomaceous earth.

Was considering putting granular iron on ground around the trees.  In your opinion, would that be worthwhile?

Thank you.

Yes, feeding is the same as fertilizing.  Overwatering as underwatering would cause the leaves to wilt and the edges to scorch.  Your yellow is throughout the leaves.  Yes too much fertilizer can cause problems but is usually a scorch look and the leaves would drop.  Too much phosphorus in the soil will cause the iron to be unavailable to the plants. 

Use iron sulfate as that has the sulfur to lower the pH (more acidic) which helps the iron to be absorb and iron to be absorbed.  This won't fix the chlorosis for this year (slow acting), but would help for next year.  Ironite is one product and it lasts 2-3 years.  I would recommend a soil test to get a reading of what your soil contains and what it needs.  Please stop feeding the high NPK  miralcle-gro, this tends to cause a lot of leaves to the detriment of roots and stems.  You can put down the iron sulfate now and no more fertilizing until next year.

Please check the Michigan site I sent you - it has a wealth of information on growing chestnut trees.

Okay, and thank you for taking the time to help with this.  We water occasionally using well water with high iron content.  Maybe once or twice a week.  Does that preclude applying Ironite to the soil for these young chestnut trees? 

Please get your soil tested as I suspect that the pH is too high (alkaline) to allow absorption of the iron.  While  you do that and wait for the results, get some sulfur from the garden store/hardware store and apply that according to the instructions to lower the the pH around the trees.  Again you won't see any change this year.  The soil test is available from your county extension office  18000 State Route 4, Suite E
Marysville, OH 43040
Phone:<personal data hidden>
<personal data hidden>

Hi, attached is the soil report.  Can you interpret for us?  We need specific info on what to buy and how often to treat area around these trees.  Do we need a broadcast spreader to apply?  Thanks for the many answers your office has provided.  New at this, don't want to make mistake.

To get a complete reading, contact your extension agent.  What I can tell you is what the cover letter told you - your soil is too alkaline (high pH) and needs to be lower (acidic) for chestnut trees.  The Michigan web site says this about soil pH and chestnuts - "

Ammonium Sulfate (NH4)2SO4 (21-0-0)

This means that 21% of the weight of the bag will be nitrogen and there will be no phosphorus (P) or potassium (K) in this fertilizer. This formulation contains both ammonic nitrogen and sulfur. Ammonium sulfate moves easily into the soil with rainfall or irrigation. Ammonium sulfate is the most acid-forming of the common available nitrogen fertilizers (one pound of (NH4)2SO4 will generate enough acidity to neutralize 5.3 lb. of free lime. We know that chestnut trees require low pH values so this fertilizer is useful in supplying nitrogen and keep the pH of the soil low. Do not use it in soils that are already low in pH (if your soils are pH 5.5 or lower, you don’t need it and don’t use it on a continuous basis). Problems can arise with the availability of other macro and micro nutrients if the soil pH drops too low.
This fertilizer is an excellent sulfur fertilizer, containing more sulfur than nitrogen (24% vs. 21%)."

Please get this fertilizer and apply NOW (0.5 pounds per tree).  do not apply any fertilizer after the end of October.  Then apply next spring at bud break ( about April 1st).  Test your soil again next year, 2 months fertilizing.