DE is made for horticultural purposes, but is sold pretty much commercial only through distributors. So I use oil absorbent products. This is Optisorb sold at O’Reilly’s auto parts.
Disney uses DE in all of it’s gardens. It is also used on professional ball fields. A sub layer of DE prevents pooling, holds moisture in grass longer. Many studies show the benefits of using DE as a soil amendment. But it is also great as a rooting medium as it holds just the right amount of water. Rot just does not happen. Impossible to over water. Makes for a perfect rooting medium. It looks like I’m going to get about 95% takes.
Tomato growers started using it about 5 years ago. Well some with great results. Although they were using Ultrasorb which is lesser coarse grade.
Pepper seeds in seed starting mix, and DE (Ultrasorb)
You can see these seeds started at the same time, the plants did better in DE.
This has been confirmed by many studies, I have links to many. I posted them numerous times on this site.