If you are trying to hot compost then you need to control the amount of water that enters your compost pile. If you are cold composting then you don't need to add a roof or tarp.

It's generally advisable to put a cover over your compost even if it's not hot composting, because some of the water-soluble plant nutrients in the compost can get washed away by the rain. The longer the compost sits there and the oftener it gets rained on, the more of an issue this is.

WG - your bins are pretty much twins to mine. But much better built. I use a piece of old carpet to cover them. I want rain to penetrate a bit (yes, even in my climate! ) because otherwise the heap can dry out since I add a lot of dry stuff like plant stems and twigs. The open front really helps when it comes to moving the full bin contents into the empty bin. That's all the turning I do. I cold compost and am patient.

I used pieces of metal roofing when I had a bin like that. Especially in winter in this part of the country, the pile can get very wet. I covered mine in the winter. In spring if it's too wet you can cover it from the rains, and it in the hot summer, a lid slows down drying, and you can open it if it's going to rain. Kinda handy if you want to manage your compost that much. But not strictly necessary.

I do not cover mine as I mostly cold compost. I am not worried about leaching as I take a hands off approach. I also don't worry about the ratio of greens and browns anymore.

A cover is better because it will allow you to control the amount of moisture in the compost.

Perhaps this video might be of some help.

http://www.growingagreenerworld.com/making-compost/

kimmq is kimmsr

Those bins do look nice. I would add something in front to hold the material if you plan to go high with it. But not as high as the pallets. For me 3ft is plenty high enuff so I can reach over from any point.

I started out to make pallet bins some years ago but ended up just using some old fencing to make a ring to hold the leaves and grass from blowing around. It works for me. It was much easier to haul home the wire fence.

I do cover my piles with an old shower curtain to control the moisture level.

Good job making those compost bins. I agree with 'gumby' about adding a movable front to those bins. I'd cut a pallet across the middle and use one of the halves in the front of each bin. Use a doubled strand of tie-wire to tie is to the front.

Yes, cover the piles. It helps control the moisture, retains heat and I suspect it helps trap ammonia in the pile, which aids in the speed of composting.

Cute dog.

That looks like my bin although yours looks much better than mine, so tidy :-)

I don't cover, we are fairly dry here in north central Texas and I usually end up sprinkling with water every so often. I had a pile turn to dust in the early learning stages of composting.

I did staple some fencing for the front to keep my dear dog out and keep the shredded leaves inside. It has a low tech fastener end ... 2 long deck screws into the pallet to catch/hook the loose end of the fencing.