Grindal Worm Culture Setup
A few notes to explain the reason for the way I set up cultures:
The internet has plenty of instructions for wet, airless Grindal worm cultures. The big breakthrough for me was figuring out that they do “not” like to be too wet, and they “do” require drier and better aerated containers than white worms for example. The trick is allowing for this in a low maintence way that won’t dry out too easily.
Container and Medium
Start with a good sized Tupperware container. I prefer the 76 oz rectangular ones pictured. They are about 5” x 8” wide and 3” deep. Fill with at least an inch of damp (not soaking wet) coco fiber. For those not familiar with coco coir, or fiber, it is sold in brick or loose form online and in any chain pet store. The extra depth is to give you some stability and room for error with moisture levels. If you go away for a week, or life otherwise gets crazy, the worms can retreat down into the substrate. As long as you don’t let it dry out all the way to the bottom, or neglect to feed them for an extended time, the culture will survive.
Please note that the good sized air space in the top half of the container.
Cut a 3-4” diameter hole in the lid and save the plastic circle you just cut out. We will be using it later on. Glue or tape some cloth or mesh over the hole. It has to be finer than window screen. You want to let some air in, but keep fruit flies out in the summer months. I am using fruit fly cukture lids in the picture because I have a bunch of them laying around.
Alternately, you can poke some pinholes in the lid. Start with less and add more as you need. You want the culture to stay damp between feedings and see the worms on top when you open it. The culture should never get any mold, or any sort of odor other than the faint smell of the coco fiber. If either of these things happen, get the mold out and get more air in.
Nothing will kill a culture faster than mold or fouling. Having said that, they are very easy and forgiving once you get the hang of it. I have had cultures go two years without fouling. These days I just restart them annually to be safe, transferring a big enough bulk of healthy worms so that production barely misses a beat.
Get the culture medium nice and flat/level. This will aid in the harvesting. The black rectangle laying on top of the medium is plastic matting used for making hook rugs. You can find big sheets of this at any craft store of a dollar or two. On top of this is the plastic circle you cut out of the lid.
The matting serves two purposes. It will keep the food and worms separate when harvesting, which makes feeding easier. It also allows a small air gap beneath the plastic disc. This will both eliminate molding and boost the productivity of the culture.
Here I have two containers ready to go. I always make at least two, just for some redundancy. For around an $8 layout in materials, two of these will have you drowning in extra worms, and giving them away to friends.
Tomorrow I will add my worms and go over getting started and feeding. Then over the next few weeks, let’s see how quickly we can ramp up production and start feeding some fish....
