Lift a damp board off a garden bed and a gray haze skitters off the rotting leaf pieces underneath. Those specks are springtails, and you want them there. Springtails in gardens feed on dead plant matter and the fungi that grows on it, which is the exact work you want happening under your plants. You do not need to spray, rake, or move your mulch on account of them. The garden springtail can turn pest in very large numbers, but that is the rare case, not the normal one.
The case for calling springtails beneficial starts with the menu. Springtails eat decaying plants along with the fungi and bacteria growing on them. Pollen, algae, lichens, carrion and the droppings of other bugs go down too. Pick up a half-rotted leaf from your bed and you are holding a springtail dinner plate. A springtail grazes the microbes on that leaf as much as the leaf itself, and the microbe population comes out better off, not thinner. Coulibaly and colleagues ran a 60-day lab microcosm in 2019 and measured total soil microbial PLFA at month two. The control soil held 627 nmol/g of dry soil, and every springtail treatment came in higher, from 874 up to 988.
Depth changes the effect. In that same work the surface dwellers pushed Gram-positive bacteria while the deep-soil species tracked with Gram-negative markers. Different springtails track with different parts of the soil food web, though combining the two groups added no extra effect in that study. You cannot sort that out by eye, and you do not have to.
Springtails in gardens are hard to count. Ohio State University Extension puts populations at up to 100,000 springtails in a cubic meter of surface soil, or many millions per acre. Almost all of that sits in the damp layer right under your mulch, which is why you only meet a springtail when you disturb something. Springtails also break down the insecticide DDT in soil, and very few organisms can do that.
You meet springtails most often when you move something. Turn a pot over, pull back your mulch, or shift a plank after a wet week and the surface comes alive for a second. That is not an outbreak. You are looking at the top of your litter layer at work, and the same thing is going on under every part of the bed you have not lifted yet.
If you keep a worm bin you have watched springtails compost scraps right beside the worms. Springtails swarm damp, half-rotted material and keep your breakdown moving. A bin crawling with them is a bin that is working, so put the lid back on and leave it. Your mulched beds run the same way. The more leaf litter you keep on the surface, the more springtails turn up to eat it.
Leave them alone. Springtails in gardens count among the most numerous soil decomposers in your beds, and nothing sold in a garden center does that job for you. Killing a springtail population costs you money and takes out the animals turning your leaf litter into food for your roots. A gray cloud under your mulch is a sign the mulch is being eaten, which is the whole reason you spread it.
The garden springtail, Bourletiella hortensis, puts up with drier ground than its relatives. In very large numbers it can be a garden pest. That is the one time a springtail population in your bed is worth a second look.
So you can answer yes for almost any garden you grow. Turn the board back over and let your springtails get on with the job.
Read the full article: Springtails: Harmless Bugs, Real Moisture Clue
