2025 Fall Homeland | After Harvest: Preparing the Garden for Next Year 

It is always a joy to garden in the spring with the promise of fresh produce for our family. Asparagus is the harbinger of the year as our family eagerly watches for the first shoots to appear in April.  

As we enjoy the fresh tomatoes, cucumbers, zucchini and green beans, summer is at its zenith. As the days grow shorter and cooler, it’s time to bring in the squash and potatoes.  

Then comes the task that many dislike. Cleaning out the garden in the fall is more of a task than a joy. I’m trying new ways to conquer the challenges that I’ve faced in garden cleanup and want to share what I have planned.  

It’s always about the soil 

As I harvest vegetables, it’s a good time to inspect the condition of my soil. Last year I sent in a sample from my main garden spots to the NDSU soil testing lab. The most important nutrients for soil are nitrogen, phosphorus and potassium – commonly referred to as NPK. My levels were 1.85 out of the suggested 32-60 for nitrogen; 62.73 for phosphorus, which should be between 8 and 20; and 42 for potassium, which should be between 39 and 80.  

The soluble salts in my soil are low, which is good. My organic matter is 5.6 percent, which wasn’t super high, but at a satisfactory level.  

Those numbers showed I needed a great deal more nitrogen, which is commonly lacking in most gardens. That makes sense, as growing plants use nitrogen to produce foliage to feed the plants. The recommendation came back to add 3 lbs. of nitrogen per 1,000 feet of soil and to use a split application.  

Several years ago, I added some aged manure in the fall, which can work to bring up the nitrogen levels and add organic matter. It’s hard to tell how much the right amount is, and some areas got too much. The next spring, plants struggled, and I realized I had added too much. I used grass clippings and leaves to lower the levels, and the garden flourished the following year. This year, I chose a 12-0-0 fertilizer to add nitrogen without increasing P or K. 

If you decide to use manure, make sure it is at least 6-months old and don’t apply more than ½-1 inch. Apply it in the fall, then lightly rake to incorporate the nutrients into the soil.  

Put the tiller away 

Chris Goldade with the Soil Health Coalition is a friend of mine. He is an advocate of no-till gardening, telling me that I need to no longer see weeds as an enemy but realize that Mother Nature is trying to do her job.  

A plant growing in an unwanted place is generally called a weed. It is up to us to decide whether we want to keep the weed or pull it out.  

Chris told me that when Mother Nature sees naked ground, she wants to start something growing there. Seeds from common weeds like kochia and thistle lay dormant, and once the seeds get moisture, they may germinate and grow. He cautioned that every time we till, we bring weed seeds back to the surface. If left alone, good plants can push out the unwanted. The key is to mulch heavily and cut the weeds down with a mower before they go to seed. Having some type of roots in the soil is preferable, even if the root is a weed.  

Mulching is an important part of gardening. When you cover the soil with straw or untreated grass clippings, it shades out the weeds and helps retains moisture. The organic material provides food reserves for the microbes in the soil after the yearly harvest.   

Smothering weeds 

In areas where there are persistent weeds, I am using occultation as a solution. This method uses tarps or cardboard to suppress and eliminate unwanted vegetation. 

According to current research, using a tarp serves as a passive method for weed suppression by excluding light and eliminating weeds or grass beneath it without needing tillage. The application of a heavy-duty tarp also uses solar heat to increase soil temperature and further inhibit weed growth. Soil temperatures should reach at least 104°F (40°C) under the tarp to effectively destroy any dormant weed seeds. 

I plan to put the tarps down this fall and take them up in the spring. Then I can rake away the dead weed foliage, add a layer of compost, and I’ll have my new no-till area to plant.  

Tarps can help you reduce soil disturbance in the garden to protect the beneficial organisms that live belowground. Chris reminds me that tillage is the mechanical disruption of soil with rototillers, plows, and cultivators. Every time you till, you destroy the fragile soil ecosystem by grinding the particles and structure into uniform sizes. 

He told me to imagine that there is a thriving city underground. In that city are billions of bacteria, fungi, protozoa, nematodes, worms, spiders, and larger animals like voles or groundhogs. Each organism has a particular home in the soil structure.  

These organisms help hold onto moisture during drought and quickly drain water after heavy storms.  

We need to remember that any time you till, it effectively destroys this thriving ecosystem. All the different particles are ground to dust, and there is nowhere for the beneficial microbes to live. This leads to big problems like compaction, where the soil becomes hard like concrete, and plant roots have a tough time breaking through. Chris assures me that by replacing my tiller with a tarp, I can build stronger soil over time and boost the soil food web so my garden gets healthier every year. 

Planting cover crops 

Planting cover crops for vegetable gardens is just another way to get food into the garden soil. The cover crops halt soil erosion, reduce weeds, retain water and provide cover for beneficial insects. In the spring, when the crops are worked into the soil, they provide the needed nutrients: nitrogen, phosphorus, potassium and organic material. 

There are a wide range of cover crops available. I’ve found that visiting with my local seed dealers and the staff at the Natural Resources Conservation Service helped me decide which mixture of seeds worked best for my garden. 

As a general rule of thumb, most cover crops require a minimum of four to eight weeks of growth before a killing frost arrives. Chris tells me that as soon as he harvests, he plants another crop. At the end of the season, that means he’s planting cover crops. The seed can be broadcast, raked in and watered. Since we never know when we will have our first frost, that allows enough time to establish a good root system.  

By conducting soil sampling, managing weeds effectively, applying mulches, using occultation techniques, and planting cover crops, I look forward to reducing the time spent on garden maintenance so I can dedicate more time to appreciating the thriving plants within my garden. That’s a win-win!