Well I really couldn't choose just one tool but I definitely have a favorite. I bought the Twist Tiller last year and really used it a lot. The feature I found handy is the cross bar at the bottom where you can use your foot to push it into the ground. The tiller is very durable and easy to use. I was out with it yesterday getting some of my garden areas ready for planting. It won't replace our mechanical tiller for big areas but it is nice for working on the many little spots I have to till. No this isn't an advertisement. I just like my little tiller. I would love to hear about what item is indispensable in your garden.
22 hours ago