Answer: Fertilization requirements should really be based on the results of soil tests rather than by guessing. Your county extension should be able to help you with some basic soil tests and interpreting the results with an eye towards the arborvitae requirements. On the other hand, if the plants are doing well with your Hollytone regime, it might be a good idea to stick with it. Coffee grinds, although somewhat acidic, would not be a substitute.
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