Fall Soil Care

Fall in the home garden is a time for harvesting edibles, composting, collecting seeds, and prepping for cooler, wetter weather. As the garden begins to shut down, perennial plants go into dormancy. Deciduous trees and shrubs lose their leaves, and annual flowers start to look tattered and brown. This time of the year is also critical for soil building; a weekend of work can ensure that the basis for all that grows in your garden is kept in good condition and is ready for next spring.

The First Steps

Before getting your hands dirty, make sure to take some time to walk through the garden and think about what worked and what didn't this year. Take note of any diseases or pests that were particularly hard to deal with, what plants they attacked, and where in the landscape they set up camp. These notes will inform your planting layout and plant choices for next year. Engaging in ongoing cultural practices like crop rotation and more resilient plant choices can go a long way in preventing these same issues from being a nuisance again.

After collecting any seeds for propagation, remove annual ornamentals and crop plants that have reached the end of their harvesting season. Make sure to safely dispose of any plant material that is diseased. Healthy debris can be tossed in the compost pile or pulled, chopped up and left on top of the soil surface. For perennial plants that die back to storage roots over the winter months, make sure to clearly mark their location using stones or flags to avoid accidentally disturbing or damaging them while working with your soil. After they have been marked, their above-ground foliage can be cut back.

Test soil by using the hand or mason jar tests. If you had any glaring issues during the growing season, consider doing a more in-depth pH test or sending your soil in to a professional soil testing company. A reputable soil testing company can be found through your local extension or Master Gardener program. If your soil has good structure and overall tilth, it may not need much amending. If soil is poor in nutrients or has structure that is not conducive to plant root growth, plan on adding a healthy amount of compost or other organic matter.

Identify any problem areas in the garden that have become compacted or have poor drainage. Compaction can occur when certain areas in the landscape are walked or driven over frequently​. Compacted soil does not have adequate pore space to allow for water infiltration or root growth and should be remedied. Another soil issue is the formation of low areas or depressions caused by settling of soil, decomposition of underground material, or poor drainage. As wet weather increases in frequency, keep an eye on these areas to determine if they should be filled in or possibly turned into rain gardens.

Once you've gotten a good idea of what work needs to be addressed, gather necessary materials, including mulch, compost or other soil amendments and tools like rakes and shovels, and then head out into the garden.

Action Items

Break down any berms that you have formed around your trees. Although these features help to keep water near the base of a tree during irrigation in the spring and summer months, during the winter water needs to be allowed to flow more freely across the landscape. Berms can get waterlogged in wintertime during times of high precipitation, and young trees and shrubs can end up drowning as a result.

Any areas that will be planted in the spring as annual displays or crop beds should stay covered over fall and winter to protect soil and provide nutrients. Cover crops are a great way to condition soil, improve structure and tilth, and add organic material. Popular cover crops include Crimson Clover, Hairy Vetch, and Fava Beans. The best months to sow these crops is in late summer to early fall (typically August through October). To sow cover crop seeds, level out the planting area and rake it smooth. Then, broadcast seeds at the recommended rate (this information will be on the seed packet). Cover them with a light layer of more soil, and the mulch over them to protect from wind and erosion. Most cover crops will germinate within a few days to a few weeks after sowing.

Fava Beans

Crimson Clover

Hairy Vetch

To tuck your garden in for the winter, add a 1-2 inch layer of compost across beds and borders. Remove the mulch cover first, add compost, and work it into the soil with a rake. Then, replace mulch. Add additional mulch in areas that have gotten bare since spring to insulate roots.

Completing fall soil care tasks ensures that come springtime, your plants will have the necessary nutrients for growth. Spreading out soil conditioning tasks also means that the beginning of spring can be spent planting and engaging in attentive integrated pest management techniques to keep the garden growing well all season long.