Potted Black Walnut Sapling Leaves Are Turning Yellow With Brown Spots

Question From: A. Kennedy - Aliquippa, Pennsylvania, United States
Q: Hello Nancy, Love your site. I have young black walnut trees in fabric pots that I hope to transplant in the fall. They’re struggling a bit, some leaves are either yellow or yellow with brown spots. I have seen some bugs/moths around them as well. Aside from critters, should I apply zinc sulfate or any other tree food? And is there an organic insect repellent, like Neem, that I can use? Thank you for all of the info here, I couldn’t seem to find much online about black walnut tree care.
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A: Plants in containers need to be fertilized as watering washes nutrients from the soil. I would fertilize them every two weeks with a fish fertilizer such as Nepturne's Harvest Fish and Kelp Fertilizer at half the recommended rate. Do not fertilize when planting until the following spring. Do keep them watered so the soil stays moderately moist. Best And Happy Yardening, Nancy