I have been mulling over this issue for a while now. I currently do dry apps, and backpack for weeds. Most of my lawns are 15,000sf+, and some are fairly populated with weeds. I can get pretty good results with the dry material on just about all but post emergent weed control. <p>Backpacking takes some considerable time on some of my lawns, especially new ones that are heavily weeded. There is also the operator error factor with backpacking, it is easy to miss some weeds. <p>I toyed with the idea of a truck mounted spray rig, but for many reasons, I have hesitated against one. <p>I got to thinking today about the Perma Green attachemnt for the push spreaders. It seems like it may be a nice comprimise. <p>I do have a few concerns though. <p>1. Weight. The website says that the unit is 11# empty, and 33# full. That is a lot of weight to add to a spreader, especially since I do a lot of hills. Do you guys not put as much fert in the hopper when using this unit? Can the unit be removed eaisly if it won't be needed?<p>2. What about the on/off system? Can you do it on the fly, seeing a patch of lawn that does not need the liquid, shut it off and then back on during the pass?<p>3. Do you find yourself using more material, compared with spot treating? If so, is the added material worth the time savings?<p>4. I use a double overlap pattern with my spreader, that is, I throw the material just to the tire mark of my last pass, (the area right in front of the spreader puts down 2x, the rest is 1x), does the double overlap have any effect on the liquid?<p>It just seems that you can get a little more consistent coverage with one of these units compared to hit and miss with a backpack. <p>So from you guys that have them, what are your thoughts on them???