Roto-Tilling in the Fall:
Fall is the time of year to add soil balancers like lime and other stronger additives. To strong for spring time – it would be detrimental, or even fatal to seeds and young plants. If soil test require the addition of such items, add them with the minimum amount of rototilling possible. You can add compost and manure now instead of in the spring, allowing microorganisms, insects etc to get a head start for spring.
Ideally, you will want to rototill your garden about 2 to 3 weeks prior to planting, adding your compost and manure at this time. This will allow the microorganisms, insects etc to re-establish (tilling upsets this balance temporarily) and begin their handy work prior to planting your seeds and transplants.