Not sure on the pressure. It's a pull-behind Fimco. Here's a link to what I have: http://www.fimcoindustries.com/trailer_sprayer_economy.html The first frost here hits usually mid October sometime....Maybe a week or two sooner sometimes. I am willing to wait till fall to spray, that's not an issue. I'll take a picture of some of those broadleafs and give you an idea, but I think they are these: http://www.bigga.org.uk/about-us/magazine/back-issues/02-2009/what-makes-aul-turf-weed/01035.html What would you suggest to spray in the fall then to kill the dandelions, broadleafs, and alfalfa? Thanks much!