Is the Diatomaceous Earth better than Neem Oil for this problem? How often do I have to reapply either of them? Which would be more cost effective? I have a large yard to treat and I don't want to use toxic chemicals but I also need something that is not too difficult to do myself. Also, do you sell both of these products?
I Need to Get Rid of Fleas in My Garden
Hopefully these articles can answer your questions: https://www.gardeningknowhow.com/problems/pests/diatomaceous-earth-insect-control.htm
You should be able to purchase either product at your local garden center. Application directions will be on the product packaging.