The large red worm, are they the European Night Crawlers (Eisenia Hortensis)? And the smaller red worms are they the red wriggler(Eisenia fotidia)? I never heard of crossing those types of red worms. But I believe that if you have enough of each type that they will propagate with enough of their own type to keep their own populations going.

Hi Billc-2007! The answer to the thread question is no There is only one possible cross breed(Hybrid if you will and nature done it over thousands of years. It is mentioned in one of C Morgans books. If worms could cross breed it would lead to a completely different species of worm and the taxinomist of the world would want them for study.

When two breeds or more are in a bin in sufficient numbers they co exist. When you buy worms from suppliers there is sometimes a mixture of worms in the bed run that is delivered. In commercial worm operations that sell worms they keep the worms seperate by visual identification. In order to be absolutly certain you have only one type of worm in a container you would pick out one pair in the process of breeding and then build up that particular pair of worms off spring in isolation and numbers. The worms you have can be identified from charts and descriptions. You probibly have commercially grown European Nightcrawlers if you google that name you will get hits like Dendrobina vanetta/Eisenia hortensis referred to as D. vannetta or E. hortensis. Look really closely at the worms and note the differences and similar size red worms without the yellow stripes will be Red Tigers( Lumbriscus rubella) referred to as L rubella. The really large common fish bait worms are Native Nightcrawlers/Canadian Nightcrawlers/Dew worms/Lob worms all are Lumbriscus terrestris referred to as L.terrestris. So have fun with the worms and get down and gritty.
larry

I should have been more specific in my question, but I think you guys still answered and helped me out with what I have. I have the regular redworms I bought in bulk and I got some red worms from a fishing store. They sale Large night crawlers and smaller night crawlers and also sell Large redworms and extra large redworms. When I got some of the extra large redworms ( and I believe they are indeed redworms because they are living and reproducing even in the past summer heat here in Sacramento) Where as night crawlers are best kept in the fridge untill fishing trip.
I am starting another large worm bin ( Plastic kind ) and I want to move the largest redwoms over to the larger bin. But I have some large regular compost kind of redworms too in a bin and in compost bins.
But as you mentioned to move only the large worms I want into the large bin and then I won't have to worry about the others. I jsut didn't want them to breed and make small redworms again like my others which I value and love to have around helping make castings. I have the EF redwoms in most everything around here. Compost and such. I wanted to move in some freshly done compost with paper and leaves to get the new worms started in ( placing it in for a week so it won't heat up on me ) then move the new worms in, but the compost would have eggs and some worms I would miss in the fresh compost. My main concern besides getting all small worms again was the situation you have with mules. A horse and donkey breed and make a mule which is sterile, so we don't have mules making mules. you have to have a horse and a donkey to get a mule. That was what I also was worried about only because I had red something about worms in a past post being sterile. I definately do not have night crawlers though. I fish with them, but really like these extra large redworms which are red and big but not as big a night crawler. Anyone know how to put in a picture, I would put a picture in of the redowms of both types next to a quarter, that way you could judge the size and see them. Thanks Bill C