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The only way to prevent all soil mites from inhabiting your garden is to replace the soil with a sterile, inert growing medium like perlite or pumice. Nutritional needs can be supplied by including them in the water supply, i.e., hydroponics.
Tiny Bugs in Household Soil
Your household soil is less likely to have the common pests found in a garden, but this does not mean some critters won’t make it indoors. They could also enter your potting soil if the houseplants are occasionally left outdoors.
The most common soil-borne bugs or worms are earthworms, wireworms, pot worms, or the larvae or eggs of other pests. Indoor plant pests include aphids, thrips, spider mites, scale insects, mealybugs, Sciaridae, or whiteflies, but none are soil specific.
If the tiny bugs in your pots look more like bugs than larvae, and they’re little, then it is most likely they are soil mites. These are tiny and almost invisible to the naked human eye (0.1 to 1mm).
If you want to find out more about worms in your soil, check out The Shocking Truth About White Worms in the Soil and How to Get Rid of Them
How to Identify Soil Mites
There are four types of soil mites, but the most common class is the oribatid mite which can be anything between brown and translucent. They measure about an eight-thousandth of an inch (0.2mm) to six-hundredth of an inch (1.5mm).
Oribatid mites look like miniature beetles and are often called beetle mites. Most often, these mites are off-white, but some can be brownish. Biigger soil mites (up to a fifteenth of an inch (4 mm)) are usually predatory, mainly eating nematodes and smaller springtails.
Thousands of mite species have specialized diets, but the most common soil mites are scavengers, feeding on organic matter and dead soil microorganisms.
Why do I Have Soil Mites?
Nature is designed to recover and reuse limited resources. Organic material is the product of dead plants and animals, filled with minerals and compounds nature needs for future growth.
The recovery of these resources is the work of the soil food web, a food chain with interlinking tiers of micro-, meso-, and macrofauna, feeding some birds and animals and making resources available for plant growth, the ultimate sun energy harvesters.
The microbiota consists mainly of fungi, bacteria, protozoa, and actinomyces. The mesobiota consists primarily of arthropods, specifically soil mites and springtails.
Working our way up the soil food web, the soil engineers, population controllers, and plant litter transformers are anthropods and earthworms.
Arthropod species form a significant part of the soil’s meso- and macrofauna. The primary soil-borne more giant arthropods include
- Isopoda – woodlouse, sowbug, roly-poly, pill bugs
- Myriapoda – millipedes, centipedes
- Insecta – insect larvae, ants, beetles, and other insects
It is natural (and beneficial) for soil to have all of these, though the macroorganisms are less welcome indoors. This has an implication for the numbers of lower-tiered organisms as their natural predators are removed.
This allows them to abound, causing springtails and soil mites to get so numerous that they become visible. Without interference, other higher-tiered organisms would eat them in nature.
Preventing Soil Mites in Indoor Plants
Soil mites perform many essential functions in the soil community, such as soil aeration, preparing the organic matter for decomposition by microorganisms, and converting nutrients into forms available to plants.
Preventing them from doing this would require killing the soil or growing plants in inert materials like pumice, perlite, chickpea, or lightweight expanded clay aggregate (LECA).
Of course, we know this is possible in hydroponic systems, but do you want to grow your houseplants in sterile soil?
Preventative Soil Mite Treatment
So, we know that soil mites mainly live off dead leaves and general organic debris. Soil mites are unique in that they can relocate if their environment no longer meets their needs. They use Phoresy, a fancy name for a soil mite hitching a ride on another insect.
It follows then that if we reduce the debris on the soil surface of your pot plant, the soil mites will pack their bags and leave. This also prevents soil mites from inhabiting your indoor plants.
Of course, suppose you farm with soil mite transporters, like the earthworms used by vermicomposters. In that case, you don’t want them embarking for a ride, so keeping the soil loaded for organic matter becomes essential.
Preventing Worm Compost Mites
Mites don’t only use flying insects for their phoretic expeditions. Worm, bug farmers, and even vermicomposters may notice tiny clusters of almost translucent mites on their worms.
Beetle Breeding Daniel Ambuehl’s YouTube videos demonstrate what to do with infected larvae or earthworms. It’s a bit long, so skip through part one and see the outcome in part two.
He uses the principle to provide the soil mites with an alternative, i.e., remove the need for emigration. The soil mites hitch a ride to escape an environment poorly serving their purposes.
As soon as the environment improves, the need for emigration is removed, and the soil mites disembark. You can use all kinds of baits to encourage the soil mites to get off the worms or larvae.
Soil mites do not harm their host, so your worms are safe. Still, they’re unhelpful visitors to a vermicomposting bin, so get rid of them.
Are Soil Mites Bad?
Soil mites abound in almost every soil type, from your garden to tropical rainforests, temperate forests, and grasslands to bogs, caves, and salt marshes. Their extreme diversity is evidence of their specialization, reproductive abilities, and adaptability.
Acarology (the study of mites and ticks) is a relatively new branch of zoology. It offers vast fields that still need exploration in species identification, behavior traits, and their impact on the ecosystem.
What is known is that acarid arachnids (mites) consist of tens of thousands of species, many of which are disease vectors. This is unfortunate because the four soil-borne soil mite classes do no harm and are, in fact, irreplaceably significant to soil and plant health.
Soil Mites in Garden Soil
Soil is a living system, and increasingly scientists are discovering that, rather than being a localized system, soil systems are interconnected, and some have been found to cover huge areas. Fungi mycelium forms a symbiotic relationship with the roots of seed plants, called mycorrhiza.
If that is impressive, fungi are only a part of the soil food web. Essentially, the soil food web is like a food chain, but a web better represents predator/prey relationships. Every part of the soil food web is essential.
Think of a mechanical clock made of springs or weights driving cogs connected to hands on the clock face. If you remove one of the cogs, the clock will no longer work, and the hours, minutes and second hands will come to a standstill.
Soil mites are an essential ‘cog’ in the soil food web.
Soil Mites Indoors
It becomes evident that soil mites perform many essential functions in the soil community. They aerate the soil, aid in decomposing organic matter and convert nutrients into forms available to plants. Preventing them from doing this would require killing the earth.
They regulate populations of other soil organisms, like protozoa, to help maintain a healthy soil food web and control disease-causing microorganisms. In turn, soil arthropods are consumed by burrowing mammals, birds, and lizards – but not indoors.
Frequently Asked Questions
It is possible (but inadvisable) to eliminate all soil organisms from your garden or potting soil. Still, you can control populations of different soil biota groups by changing the food supply. Soil mites thrive in soils that offer a lot of organic matter to feast on.
To reduce soil mite populations, you should control the levels of plant debris on your soil surface. For more information, check out the Sanitation Practices for Soil Mites post.