If you don't want to conduct electricity to the backyard, then you can use extension cords or LED lamps on batteries. I found here bestlightguide an article about different LED work lamps. I want to buy a few of these. Firstly, they can be configured and placed where it's convenient, secondly, they have a long working time without charging, thirdly, you can take them on a camping or a trip. They are quite compact and bright. It seems to me that this is a good choice for the backyard.