Tilling a garden in the spring is a “must” for many gardeners. But fall is also a perfect time for tilling the garden area. If you choose to till in the fall the best time is right before the first frost.
By tilling the garden in the fall you will work in any leftover and healthy garden matter. You can add compost, fertilizer, leaves, straw or peat moss. These materials will have all winter and early spring to add more nutrients to the soil and in the spring you will find your soil is loose, rich in organic material.
These added nutrients will help to build strong healthy plant roots for your spring crops. As your soil is turned it allows for better air circulation and helps with the decomposition of any added organic matters.
Fall temperatures and the soil moisture are more favorable to tilling because they help with the decomposition of added composts. Fall tilling will also help to prevent the growth of new weeds in the spring. It will disturb the soil and prevent garden pests and insects from over wintering in the soil.
In the fall when the soil is roughly tilled it will hold more snow, which in turn will improve the soils moisture, levels which and will improve the soils drainage conditions.
One other advantage of a fall tilling is that in March you will have an area that will be ready for early spring crops. The freshly tilled soil, which will not be packed down, can easily be worked with a spade or pitchfork and peas, onions and lettuce can be planted quickly. My spring weather can be unpredictable and sometimes too wet to till so a pre-tilled garden makes early planting easy.
I try not to till the soil more than twice a year. Too much tilling can cause damage to the soils structure and its balance of needed microorganisms. It also makes the soil more susceptible to runoff during heavy rains. (Another reason to use mulch in garden beds.)
Over tilling can also ruin well-established garden soil by burying some organic matters that need to be near the top to break down properly. Tilling once a year is still recommended by many gardeners and farmers. Fall tilling simply allows your organic matters to break down right into the soil over the winter enriching it for the spring planting.
And many gardeners have gone away form tilling altogether by using square foot garden methods or lasagna gardening. The main point to remember in the fall is to make sure you have cleaned up any diseased plants or weeds from the garden area and added materials that will enrich the soil for next years gardens.