New to the lawn biz, but I've been snowplowing and landscaping for 4 years. I've seen a lot of great suggestions for tools and safety gear, but I haven't yet seen something that I do...
Keep a 3 ring binder in every truck. Put the following info in the binder:
Have your emergency contact information on the VERY FIRST PAGE. Include numbers for the local poison control hotline, local hospitals, and your insurance agent. Of course, don't forget cell numbers for your foreman/manager/owner, in case the office is deserted.
Keep a safety checklist/log sheet in the binder. Make these simple daily checks (lights+lenses, horn, brakes, mirrors, etc) and weekly checks (oil, trans fluid, belts, hoses, plug wires, tire pressure, lug nuts) a part of your log. In an accident lawsuit, this log may save your bacon. This log sheet is also a requirement if you have a USDOT registration (we do).
Have copies of MSDS (Material Safety
Data Sheets) for every chemical you use, and don't forget gasoline and diesel. This is an OSHA requirement.
Also in this binder, keep copies of the driver's licenses and medical cards of all authorized drivers for your truck(s), copy of the insurance card, and a copy of the cab card part of the title.
Keep a list of all the equipment you have in/on the truck and trailer, including SERIAL NUMBERS. When (not if) something gets stolen off your truck, it will make it that much easier to report.
Last but not least. This is also a good spot to keep a price list or other "ballpark" quote guide for your on-site staff to look at. Every employee that might come in contact with a customer or prospect should have some sales literature at hand, even if it's only a business card.