1. How do you save your worms from pests like rats ?
Moles and voles are bigger threats. In my outdoor bin/pit, dug about 18", the bottom is lined with hardware cloth. In the open windrow, the worms are on there own as they would be naturally.

2. How do you create aeration in the system ?
There is no need - the worms live in the upper layers and their movements create air space. The notion that worms require special aeration by us just doesn't make sense when you observe what happens naturally in a compost or manure heap.

3. How do you drain out excess water during rainy seasons ? I understand that accumulation of water can lead to worm death.
Unless you line the bed with some material, or perhaps dig out a clay boat, the water should drain just fine. You might want to cover the pit/bed/windrow in some way to shed excessive water (e.g. heavy rain).

4. How much water needs to be sprinkled on these pits or it that it shouldn't be sprinkled at all ? Depends on the weather - temperature, humidity, etc. Water as needed to keep the bed good and moist - again, if drainage is good, you shouldn't have concerns about a little too much.

Thanks. Some clarifications

In query 1, Can the voles/moles be kept at bay by covering the bottom with hardware cloth ? Is it not required to cover the sides of the pit as well as the top with the same ?

ultimately nothing will keep rodents away from decomposing edibles, but they'll not likely tunnel into a pit unless there's lots of food waste available - rodents do not eat worms, they happily co-exist

Bill

Hi Ramm, I have not dug a pit for worms, but I have two bins, plastic and wood that work great. I also have several compost bins, that did heat up in summer but have gone cold and I just let it stay in cold decomposition until spring when I use it for my garden. I also in late fall started making a Lasania garden and just put down a layer of leaves, grass and compost and put another layer, leaves, grass, compost with some pigeon manure. I had it piled up in a hill 15 feet long and three feet high or more. It might have heated but I don't think so. The compost I put in had some redworms in it and they have really multipied. It shank to about 2 feet now. I put in pumkin, Zuke squash and old fruit, in the top inch or so. It is full of worms. I have covered it with a 4 foot wide black plastic to keep most of the rain off it. I remove it sometimes to get everything wet but only for a day every two weeks.
It is kind of like a dug in bin except it is just not dug in. I am going to get some bricks and surround the pile in spring for tomatoes and vegetables.
If it was dug in it would fill with water here. I have to have raised beds because I have a hard pan two feet down and the water collects on top and if I rotatill in the fall you sink up to your knees with mud as the water has no where to go. I plant to keep feeding the worms once I start the garden in the corners and move them around from time to time. I will try and put in a picture in a few days. I don't have problems with moles, gophers or rats but I did have rats and mice in the compost piles when I first moved here 10 years ago.
So I would build up a worm bin instead of digging one down in the earth. Bill C

I have a composting hole and I am about to make another to put my 3/4 finsihed compost heap on. Nothing bothers the composting holes. I layer the hole and cover it with carboard. Kitchen scraps, green matter, paper, cardboard, each time I put in scraps, I layer and I cover it with a carboard, I'm in Oregon and it works alright. Old books says you can cover with burlap, wet down and cover with board for no pest problem compost hole. They say long and narrow about 18" deep. My next hole will be that way.

are bay leaves bad for red worms