There are certain situations when using Milorganite should be avoided. Firstly, if you have recently overseeded your lawn or applied herbicides or pre-emergent weed control products, it's best to wait until after the newly seeded grass has germinated or until the specified waiting period has passed before using Milorganite as it may interfere with seed establishment or herbicide effectiveness. Additionally, if your plants are already showing signs of nutrient deficiency or stress symptoms due to waterlogged conditions or disease, it is advisable to address those issues first before applying any fertilizer like Milorganite. It's always beneficial to assess your plant's specific needs and consult professional advice if unsure whether using Milorganite is appropriate in a particular situation.