Q: I recently bought aerator sandals with two inch spikes on the bottom. After I purchased them, my brother-in-law told me I wasted my money because aerator sandals do not really work. Are they really harmful to the grass or are the holes good for the soil even though no dirt is being pulled up out of the ground?
A: Unfortunately for your ego (and wallet), the aerator sandals are little good for loosening the soil of your lawn. I hate to give your brother-in-law ammunition for teasing but he is essentially correct. Spikes, whether on sandals or a pull-behind lawn implement, compact the soil. The best aerator is one with hollow tubes which pull cores of soil from the earth.
However, the spikes ARE good for something else: grub control. The sandals showed fairly good results in killing lawn grubs in a Colorado State University study. Researchers walked a turf plot three to five times to achieve an average of two spike holes per square inch. If you have white grubs (the precursor to Japanese beetles) using the sandals against them will provide hours of entertainment for the neighbors and aerobic exercise for you!