Ideas, make a few dollars more by planting bulbs. Tulip, daffodils, hyacinth, crocus, snowdrops.
Spreading bark mulch, of course.
Maybe treating the bark with pre-emergent.
Maybe there are local favorites, plant bushes, and perennials.
Take soil samples for soil tests. Use pH meter. Send to a lab--OR--do them yourself with a top-notch soil test kit. Charge for this--or--do it free for goodwill--and to prove that your company is better than your sleazy competition. Find the percent sand, silt, clay and organic matter.
Maybe you can learn how to do a soil biology (soil health) test. There must be a kit somewhere. Or a special lab.
Overseed rye on Bermuda for winter green?
Dormant seeding? Or overseeding? Using improved cultivars of turf-type tall fescue? Not many people believe in this--so--you would have to guarantee satisfaction. In theory, the seed would sprout in spring when the soil temps reach about 55.
Also, you can sample for grubs. Look for thin spots. And any area where the sod can be easily lifted from the soil. Schedule grub control if needed.
Try to penetrate the soil. This to determine compaction. You may have to devise a device to determine the force needed to penetrate with a soil probe. Unfrozen soil, of course.
Winter is a good time to improve your marketing brochures, website, and mailers.
Maybe emphasize your natural-organic aspects. Check out what other companies and other industries are doing. Customers want to avoid environmental damage, and hire earth-friendly companies. Maybe one round can be organic like "Screamin Green". Maybe you can use low odor, low-toxicity biodegradable products.
Maybe you could have a sale, off-season specials. Mole control--treat tunnels or dens with some obnoxious smelling chemical. Hand or back pack sprayer. Shove a metal nozzle through the tunnel and spray some stinky chemical at intervals. If you can find the main den--so much the better. Predator urine. Coyote urine? Do you have a cooperative dog? Can your dog find the tunnels and dens?
Also winter may be a good time to eliminate the resistant weeds by hand. Violets?
Dallas grass? King Ranch bluestem? At extra cost or as part of your program to help you compete with cheepos and hurry green. Need features that they do not have.
One more. I noticed that lawns on my street are rather flattened down--now that the snow is melted for a day or two. Seed applied now will have no trouble falling down to the soil. Thereby achieving seed to soil contact. Should arise in spring about the date of the first mowing.
You can also, have a special sale on minor landscape projects (that are possible in winter). Can you fix a dead spot with sod?
Can you buy sod at this time of year? You probably know someone who knows someone.
Maybe in late winter you can pre-germinate some seed for quick response on spring seeding projects.
Plant fat milkweed rhizomes to help the monarch butterflies?
Snow has been few and far between for is in the KC area this winter so I have been working on renovating a bathroom, got all my springs letters done and sent out, finished Assassins Creed Vahalla (yes Im 48 and play video games), worked on some mowers that needed attention, had kidney stone surgery last week, getting some naps in and working out.