m0useanswered grow question 5 years ago DE or diatomaceous earth is a good option for combating bugs but it is a slower process and only in the right circumstances, eg it's like walking on glass for the bugs, it cuts them open and they slowly "bleed out" or dehydrate and die. it is a non-discriminate killer and will hurt friendly bugs as well in your garden should they come into contact with it. So its a bit of a negative in that sense. as you really need the friendly ones.
Other downsides are it only works when it is dry, and out side there is a lot of wind, so it blows away easily. If it gets wet, it will only be beneficial when/if it dries out again.
In my experience, its "ok" for indoors but outdoors not so much, unless u tossing it on an anthill or beehive.
It can/is a respiratory irritant as its in such fine particles, I view it as a lesser asbestos inline with talc, I prefer to use it as a bug deterrent under cabinets and between walls vs in the garden as bugs know its bad for them and wont cross it if there is another option. If you got a bunch leftover mix it in with the soil its also a calcium booster. :)
The best way to keep plants healthy outdoors is something called companion planting, get a bunch of herbs/flowers and plant them in the same area. Cilantro and Chives attract beneficial predators that eat the pests. Marigolds and Mint put off a lot of bad critters and bring in swarms of predators, cheep and readily available as plants or seeds. I have noticed a complete 180 on my garden when I started doing this. Granted I grow a wide range of things from tomatoes and peppers to flowers and herbs to cannabis all in containers. One other thing that helps is not using synthetic fertilizers. they fuck up the soil microbe life, that affects the plants and makes they more prone to infestations. look up Acti-sol as a natural fertilizer, its great stuff, perfect for basic garden stuff.
m0use