How to Feed Your Soil in the Fall in 10 Easy Steps
Fall is the perfect time to layer on the organic materials and give back to your garden soil. Former organic farmer Logan Hailey guides you through feeding the soil microorganisms, loosening your beds, and protecting your precious garden dirt before winter.
Autumn is the ideal time to give back to your garden soil. After yielding so much abundance through the summer, it needs replenishment to prepare for the next season. Vegetables, fruits, and ornamentals use varying amounts of mineral nutrients and water to fuel their growth.
You might have heard the philosophy of “feed the soil” rather than “feed the crop.” In other words, adding organic matter and decomposable materials (like manure or leaf mulch) provides food for microorganisms. Those microbes make nutrients available to plants. Feeding your garden soil means providing biodegradable materials like plant matter, manure, and leaves to fuel microbial activity throughout the winter.
Let’s dig into ten simple steps for nourishing your garden dirt in autumn.
Should I Feed My Garden in Fall?
With its abundance of fallen leaves, discarded straw bales, and manure, fall is the perfect season to amend your soil. Additions of organic matter and nutrients fuel the microbiome, promoting more significant biological activity and richer texture for the following season.
In annual vegetable beds, this is a great way to “put your beds to sleep” so they are ready to plant come spring. For perennial beds, fall feeding helps plants transition into dormancy, improving frost tolerance and promoting strong spring growth.
10 Steps to Enrich Fall Soil
Replenishment is all about feeding your garden’s resident microorganisms. The below-ground ecosystem is far more complex than only earthworms and spiders. Billions of microbes, including bacteria, fungi, protozoa, and beneficial nematodes, reside in every pinch of healthy soil. This soil-dwelling microbiology works 24/7 to digest and decompose materials so plants can uptake their nutrients.
However, disturbed soils with low organic matter tend to have fewer microorganisms. This can pose problems for garden plants because they can’t consume fertilizers without their microbial allies’ aid.
Enriching in autumn allows microbes to regenerate their numbers and prepare nutrients for spring crops. Here’s how to do it:
Leave Crop Roots In Place
When your plants have dwindled, and it’s time to clear your beds, it’s a natural impulse to yank everything out by the roots. But leaving the roots in place could actually be your first step to improving your soil for next season. You can cut the plant off at the base, just like pruning an herbaceous perennial plant that dies back to the ground after a frost.
This standard “no-till” technique reduces disturbance and provides many root tunnels and air spaces for microorganisms to fluff up the texture. This is particularly useful if you have compacted ground or heavy clay. The roots will slowly decay over the winter and turn into rich organic matter by the spring.
Another benefit is erosion prevention. The roots hold the dirt in place so you don’t lose any to wind, rain, or winter storms. Although you should cover your beds anyway (more on this later), the roots keep everything more stable. This is especially useful if you garden on a hill.
Finally, and perhaps most importantly, many types of plants house nutrients in their root system. Legumes such as beans or peas produce nodules on their root systems that hold nitrogen; buckwheat roots pull phosphorus up to the upper soil profile. By allowing these roots to decay into the soil, we provide a slow-release, natural supply of these plants for our future crops.
Cut and Compost the Foliage
Use loppers or sharp pruners to cut off plant stems at the base. Remove the above-ground foliage and take it to the compost, leaving a bare bed ready for further amendment.
Another option is mowing. If your garden beds are ground-level, you can run a lawn mower or flail mower over the bed to shred up all above-ground foliage and leave the roots intact.
Avoid Diseased Plants
Never leave diseased roots (like root rot or club root) in the ground, as they can become harbors for pathogens. If you suspect a diseased crop, remove it entirely and throw it away. Avoid composting infected plant material.
Chop and Drop
The “chop and drop” method is a sustainable gardening technique commonly used in tropical food forests and permaculture gardens. It involves pruning back plant material and leaving it on the surface as mulch to decay into organic matter.
This mimics the natural cycles of nature. For example, in a forest, leaves and debris naturally fall and decompose in place, which is why forest soils usually have a rich “O” layer full of decayed pine needles, sticks, logs, and mushrooms.
Avoid Dropping These Crops
This technique may seem surprising from someone who often warns you about leaving crop debris in your garden! It is never a good idea to “chop and drop” crops like tomatoes or squash that are super prone to disease. The dropped plant residues become a breeding ground for pathogens and pests over the winter. Instead, you want to export the stems and leaves to your compost or burn pile.
However, this method is excellent for soil-amending plants and cover crops rich in nutrients. Generally, “chop and drop” is not used on vegetable beds except for leafy greens like lettuce or spinach, pulse crops (beans, peas, lentils, etc.), and some herbs.
Dynamic Accumulator Plants
Great “chop and drop” candidates are sometimes called dynamic accumulators because they pull up minerals deep in the soil and make them available to other plants. By dropping their prunings to decompose during fall, you add an abundance of nourishment for your crops.
Dynamic accumulators include (but are not limited to):
Simply prune back the leaves and mulch them over the ground’s surface. Avoid leaving behind seed heads, or these plants may get out of hand. As always, only “chop and drop” if the plant foliage is free of disease and pest infestations.
Incorporate Aged Manure
Adding composted, aged manure to the garden in autumn is an excellent way to add fertility for the next season. Manure can sometimes be too high in nitrogen, especially if it isn’t aged. By adding it in the fall, you ensure the microorganisms have ample time to break down the cow poop (or pig or chicken) into a form easily digestible by plants.
Simply spread the aged manure evenly over the top of your beds, covering the residues left in place from any of the above steps. Aim for a layer 1-2 inches deep, and water the bed to ensure it is sufficiently moist to break down.
Remember to use pre-aged manure sourced from a local farm or your own chicken coop. Fresh or “hot” manure can burn your crops! Months of overwintering will reduce the risk of nutrient burn, but it’s still best to source aged or composted manure whenever possible. It stinks less and poses fewer health risks than raw, fresh poop.
Layer on the Compost
Finally, the fun part! Fall is the best time to add compost to your garden. The compost can continue aging in place and nourish the microbes while you stay cozy indoors. The layer of compost is the nice “icing on the cake” to cover up the rotting plant debris and manure. It is what you’ll plant into the following spring.
When applying compost to garden beds, it’s easiest to dump bags into raised beds or use a wheelbarrow for in-ground beds. I recommend doing the heavy work up front by dumping several big piles a few feet apart. Then grab your rake and smooth it out.
This is also a perfect time to check on your compost bin, turn it, and take winterizing steps like protecting the pile from snow and rain. You don’t want super soggy rotting plants to smell up your spring garden!
Broadfork and Loosen
Now that you’ve removed your crops, added manure, and smoothed it out with compost, it’s time to incorporate the soil slightly. The key word here is slightly. You don’t want to overturn and chop up your soil, and you want to avoid rototilling if possible. With less disturbance, your ecosystem will be healthier for the coming seasons.
Research shows that no-till soils are significantly healthier than tilled because the beneficial bacteria, fungi, nematodes, and other microbes can maintain their communities with disturbance. This means healthier plants, fewer disease issues, and higher yields for the gardener.
The Best Aeration Tool
If you don’t rototill or turn and chop your soil with a shovel, how will you loosen it up and incorporate the new amendments? A broad fork! This unique tool is the absolute best way to aerate garden beds without harming microorganisms. The long tines dig in and create air space channels for oxygen to enter the deeper levels. Simultaneously, the compost, manure, and plant residues sink into the holes naturally.
The benefits of broad forking include:
- Reduced compaction
- Oxygenation for deeper soil levels
- Looser, fluffier texture
- Less disturbance to beneficial fungi and bacteria
- Easier plant root penetration
- Long-term soil health
Consider adding a broad fork session to your autumn regimen if your soil feels hard or overly compacted.
Rake It Flat
With everything nourished, fertilized, and aerated, it’s time to go to town with your rake! A final smoothing of the bed surface makes everything nice and tidy before you add your final layer of protection. This is mainly for ease of planting when spring arrives.
If compost is the icing on the soil cake, mulch is the sprinkles! You could consider mulch the most underrated garden hack of all time. If everyone added mulch to their garden, the world would be a better place (and it would be way easier to control weeds!)
Mulching helps to:
- Suppress and smother weeds
- Conserve moisture
- Protect from erosion and compaction
- Improve organic matter content
- Moderate temperature
- Protect tender perennials from frost
- Nurture and protect microorganisms
- Improve carbon levels
Technically, any biodegradable plant residue can be a mulch, but the best mulch choices for a garden are quick to break down and free from contaminants like seeds or herbicides.
Mulch vegetable beds with straw or shredded leaves. Use shredded bark or wood chips in hardy perennial and ornamental beds.
If using a tightly tangled straw bale or compacted bag of mulch, fluff it up with your hands first. Then, spread a thick 4-6” layer over the bed surface.
Don’t Forget the Pathways
Even though you don’t grow crops in pathways, they are still worth attending to if you want to reduce weed pressure. Mulched pathways also provide a more enjoyable gardening experience and less muddy boots.
Wood chips, leaves, straws, and even nut hulls are all great options for pathways. I like to use bulkier, carbon-rich materials for paths because they break down more slowly and suppress weeds for longer. You should also consider what you like to walk on. If you want to meander through your garden barefoot, leaves will be far more comfortable than bark.
Remember, the best mulch is always cheap and readily available. In many towns, you can have a dump truck of fall leaves delivered to your house. If you live near a pumpkin patch, you can always ask for their straw bales (assuming they aren’t treated with herbicides).
If you know a local arborist, ask them to drop off some wood chips next time they prune trees nearby. It’s a win-win situation because one man’s trash is another man’s treasure! In this case, the leftover plant materials from other industries become the perfect nourishment for your garden.
Tarp and Protect
If you want to go the extra mile, a final cover will help protect and nourish the dirt to ensure the richest, loamiest soil next year. Secure a tarp over the bed with smooth rocks or sandbags. Add more weight than you think because you never know how harsh the winter winds will get.
The tarp will prevent your bed from getting pounded by rain and snow. Even though they can accumulate on top of the tarp, they won’t drench and oversaturate the layers underneath. A tarp also keeps your mulch from blowing away and prevents rodents or pests from making a home in your dormant garden.
Start New Lasagna Garden Beds Or Hugelkultur Beds
Once your existing beds are fed and protected, consider using extra time in the fall to prepare new garden beds. The “lasagna” method of gardening involves layering all the organic materials of autumn into a bed and allowing it to compost in place to create a fantastic new planting bed for spring.
You can create a lasagna garden as a mound on the ground or inside a raised bed to save on store-bought soil. The premise is simple: layer the heaviest and woodiest (slowest to break down) materials on the bottom and slowly work your way up to the finest layer of compost. Many sticks, tree prunings, herbal cuttings, and decomposing leaves are available to craft the perfect garden lasagna!
Use any non-diseased plant material readily available in your garden or landscape. For example, this is how a lasagna bed would be layered from bottom to top:
- Thick logs (the bottom layer of the bed)
- Thinner sticks
- Tree and shrub prunings and twigs
- Grass clippings
- Shredded leaves
- Compost or vermicompost (the top layer)
Instead of covering these beds, I like to leave them exposed so they can break down with the help of the elements. Once established, I shift lasagna beds into the standard rotation of fall preparation described above.
Another method, called hugelkultur, uses a similar process. In hugelkultur, you begin with a base of dry logs, topped with thinner sticks, leafy material/grass clippings, and then your soil. This method traditionally piled the logs high to create a tall mound with at least 6-10 inches of soil covering it once constructed.
With hugelkultur, the wood is the star. Wood takes time to break down, so it will last for an extended period (sometimes years), gradually becoming a sponge that retains moisture for the plants growing on the mound. A modified form of hugelkultur is often used in raised beds to reduce the volume of soil required to fill a taller bed while providing additional benefits as the wood slowly decays.
Ultimately, the secret to autumn garden nourishment is layering on as many organic materials as possible. If you have leaves, straw, cover crop residues, leafy greens, grass clippings, wood chips, or any other natural biodegradable material, it can help nurture your soil. Remember to avoid any diseased or infested plants.