Join Date: Aug 2013
Location: Van Isle, BC
Repost from "gnat attack"
Copied from an email I got from a wicked resourceful local grower.
The soil-dwelling Hypoaspis miles mite is one of my favorite wee beasties. Commercial potting soil is dense enough that they can only occupy the top 1cm of soil.
When i raised them, i used hydroponic store expanded-clay pellets as a media, with a sphagnum wick throughout as a water/humidity source. Use unmilled fibrous sphagnum -- the coarse woolly stuff from deep woods. The best quality sphagnum is that which you pick yourself. Drench it with boiling water to oust potential pests, rinse thoroughly.
Assembly: take a 1-gallon pot , hold a narrow (5cm) wad of moss in the center of the pot against the pot's "floor". Backfill all around with pre-rinsed, still-wet clay pellets. Hold another wad against the top of the first one, backfill again. Continue to within 5cm of pot rim. In a potful of pellets, you now have a narrow vertical core of moss.
Set within a tray holding 3cm water. Tray must be wide enough that it doesn't touch the pot's sides. Not only do you now have a water source to wick moisture (or at least humidity -- Hypoaspis drown readily in too much free water) thru the media... you also have a "moat" to contain them.
You need a dark cabinet or ventilated box -- they are photophobic.
I used "micro-worms" (Anguillula silusiae --not to be confused with "white worms"), as they are known in the aquarium trade. These 1mm long nematodes are an intermediate-sized live food used for fish fry. No pet store in this area carries them. Befriend someone in an aquarium club if your local pet merchants also fail to.
Raising them always seems to raise a pervasive sour stench, like a sourdough culture that spoilt 2 weeks ago, and this is absolutely unnecessary. It never smells nice, but the odor can be greatly reduced.
All the aquarium hobbyists use a substrate (grain-based) at least 3 cm deep, with all the attendant anaerobic putrescence. Thus, only the top 5mm are habitable, and the culture senesces because of toxin buildup, not because the food supply attenuates.
A 5-10mm layer in the bottom of a 500ml yogurt container will not go foul. It will last as long as the other method (best changed every week, though, to maintain vigor). It WILL dehydrate quicker, and 100% humidity is better for them anyway. Place the yogurt container in an ice cream tub with 1-3 cm water, cover with fine mesh (fruit flies and other insects' larvae will otherwise contaminate it).
Quick-cooking oatmeal is the easiest substrate to provide. Use extra water to produce a thin porridge or thick soup consistency.
Pour or smear a thin layer of your starter culture on the porridge. Depending on temperature, you can begin using the culture in 1-3 days.
I used pieces of unbleached coffee filter paper as "dinner platters" to feed the mites. Just snip them into one-sixth-of-a-pie wedges, and, using tweezers, touch one side to the nematode culture. If porridge tends to stick, then first mist culture's surface with water.
Lay paper, wormy-side down, on the clay pellets. Next feeding (1-3days later, depending on temperature and mite population), lay the next piece of paper beside the first.
Note that eggs are frequently laid as they eat, thus are all over that paper. Thus, whenever you need to remove a paper scrap to make room for a fresh serving, you should pin it to the soil surface of a potted pepper (or whatever) as an innoculum. Leave it for 1-2 days ( their eggs' incubation period). Covering it with a light sprinkling of damp potting media should help prevent dehydration. NOTE: grab that paper scrap the instant light strikes the mites' habitat so they don't escape.
I believe that this system has a flaw: it will selectively breed for a weaker mite. A metaphor: keep a kennel of wolves, feed and rear 'em like poodles. In a few hundred to a few thousand generations you have large scruffy grey poodles. Poodles are ineffective predators of, say, caribou. Anguilula silusiae is the equivalent of poodle food. I always meant to isolate one of the smaller species of, say, springtails, as a food organism. They're pretty much a caribou in this metaphor.
Breed your own beneficials! Share with your friends! Almost cooler than pet rocks!
The caveat at the end is interesting, and I wonder if there is a better food source/method for the Hypoaspis. I haven't really researched this or any variations yet, and am a ways away from trying it out, but it's good enough to share as is.