I want to start composting my yard and kitchen waste and use the compost to fertilize vegetables in my raised bed and some fruit trees I have. Right now I am not doing composting. My options are do nothing or use one of the smaller bins (pictures below) that are available through Costco or my city. The other option is to buy a larger composting bin (I heard 1m x 1m is the minimum). If that is the preferred option, can someone recommend a bin and whether it would be okay to keep that bin on concrete vs. having it sit on the soil. Dimensions of the City Compost bin is 28x28x30 inches
I've tried 2 bins similar to the picture on the left. They did not work well. They took a very long time to break down the compost. It was difficult to turn the pile because it was so small. They filled up way too fast because they were so small, and stayed full because they were inefficient. I ended up selling them both and using the money to buy wood to build my own bin instead. It was the best decision I could have made (short of going straight to the build-my-own solution and skipping them altogether).
Instead, I'd highly recommend looking for plans on line to build your own bin. It should be at least 1 cubic meter. Beyond that, it can be as fancy or as simple as you like. If looks are important, you can make it look like a small fenced in area and use a nice wood like cedar. If looks aren't as important, you can use less expensive wood with wire fencing in between. IF you have minimal building skills/tools, there are designs that have you affix 4 pallets together to form the walls of the bin (although I'd be a bit careful about where you get the pallets, since many pallets are treated with chemicals to keep insects away. Apparently, pallets with the letters 'DB' on them are untreated and safe for use). Any of these options will work far better than the plastic bin. I would place any of these bins on soil, rather than concrete, if at all possible.
As for the tumbler - I have never used one myself, but a good friend has one. If you don't have a good supply of brown material to go with your kitchen scraps, it will get very slimy and smelly inside, and if you have a lot of kitchen waste, it will quickly become too heavy. That said, if you are willing to turn it daily and watch the mix of browns (leaves, straw, etc.) and greens (yard clippings, kitchen scraps), it does work quickly and well.
Sitting on soil allows worms and other critters to enter and exit the bottom of the bin. Also, I would think the drainage would be poor and you could get an anaerobic smelly mess at the bottom.
As another alternative, I have had good experiences with http://geobin123.com/ . My mother has had one for almost a decade and it hasn't degraded at all.
All of the other products that I have seen are either too small (including all the tumbler varieties) or outrageously expensive. If you have the space, I recommend the geobin or building your own 1mx1mx1m cube out of wood. Something simple like 1 of the 3 square areas in this picture is more than sufficient:
Be sure and check with your local city - they may have a composting program where you can get some training and a low to no cost bin (Long Beach has one). I recommend a bin like the brown one situated on the ground in the OP. Put it on the ground directly - The compost bins at my kids' school were placed on a bed of gravel to keep the bugs out - why would you want to do that? If it gets too slimy, add "brown" material (straw or shredded paper works great) if it gets too dry add water. Resist the urge to "turn" the pile - you don't need to. Make a pit in the middle for new material and pull the material off of the sides to cover it. Pull the finished compost out of the bottom, tossing any un-composted material back into the bin as you do it. It's really pretty simple.
Just picking between these 3, the tumbler is the easiest to turn and seems the most sturdy. I bought one of the square flat-pack options and I've had no end of grief, I've just bought a small second-hand dual tumbler for foodscraps and the veggie beds, and I'll relegate the square one to lawn clippings and prunings for compost to use for non-edibles (Our soil is high in lead). All this being said, seriously consider the other answers or building your own tumbler using feed drums.
In order to select the best compost container for your garden, you need to understand how composting works as otherwise it's potentially a hit and miss affair.
The different types of composting range from hot composting which can reduce a pile in 18 days, to a cold pile that can take a year or more. Given time, any container you use will not stop the natural process of decomposition, and some will accelerate it. However, some people say that poorly made compost can unbalance your soil so that it degrades it, leaving you worse off than if you had never added it to the soil.
Most people talk about trying to create a hot compost pile. This is a pile of organic matter of a minimum of 1 cubic metre. The size is important in that less then that will not allow the centre of the pile to reach the correct temperatures to grow the correct bacteria that do the decomposition. The composting bacterial march starts with psychrophilic bacteria (55 - 70 deg F), then mesophilic (70 - 100 deg F), and finally thermophilic (113 - 160 deg F). Since these are aerobic bacteria, you need to aerate the pile, and turning it by moving material from the outside to the inside provides more food for the bacteria.
I like to think of a compost pile as a nuclear pile. The nitrogen based material provides the energy for the decomposition process for the bacteria. Carbon rods are inserted to moderate the process. Not enough carbon causes the pile to become an anaerobic mess that is likely to go nuclear and upset the neighbours. Carbon slows the process down, and a carbon to nitrogen ratio of 30-60:1 allows for orderly decomposition with minimal nitrogen loss from oxidation. Too much carbon causes the pile to cool and become inert.
In order to get the right ratios of carbon to nitrogen, you can look up tables of the carbon:nitrogen ratios of the vegetation that you add. Or, just consider mature plants at the end of their annual/biennial lives carbon products, and immature plants nitrogen products. If you mix equal layers of mature vegetation with immature, and some soil, you'll get a ratio of 30:1. If you use 3 parts mature to 1/2 part immature, and 1/4 part soil you'll get C:N of 60:1. Piles that create high carbon compost lead to superior nutrition for plants, remembering that we, and what we grow, are all carbon based life forms, and carbon forms the skeleton of all organic life.
Given the above, we can see that the commercial products you illustrate above, do not generally achieve the volume to achieve a hot compost pile. Instead you'll achieve a warm or cold composting system that will take a long time. I suspect that's why many bins are black, to try and add additional heat that is not supplied by the pile to help composting. Some tumbling systems are made of metal which might also allow them to heat up more easily from the sun so that they can hot compost.
So, the choice of system depends on your circumstances, how long you're prepared to wait, how much material you want to compost, how much labour you want to use to aerate/turn the pile, and the weather.
I had a tumbler like the sun-mar 200 on this page: http://green-living-made-easy.ultimate-online-services.com/compost-tumblers.html, but the stand wasn't strong enough to bear the weight of all the compost and it broke pretty early on. I kept using it, just rolling it along the ground for quite a long time after that, but it was pretty silly.
When I moved I got a double tumbler similar to the one in the upper left picture. I think this was it: http://www.tanksforless.com/p/984/lifetime-dual-compost-tumbler I got it at costco. I love it. The tumbling action is great for speeding the composting, I get virtually no smell, so I can keep it close to the house (in particular, close to the kitchen), and I love being able to fill one half, then fill the other half while the first batch is composting.
HOWEVER, after about 2 years, the latch on one of the tumblers rusted solid, so I can't spin it effectively anymore. I haven't tried any rust remover yet, so I can't say whether it's fixable, but I think it's safe to assume that it's a common problem for this kind of composter.