Home » Gary Zimmer on Transitioning to Organic, Biological Farming

Gary Zimmer on Transitioning to Organic, Biological Farming

Gary Zimmer standing in field
Gary Zimmer on his organic farm in Wisconsin.

By Gary F. Zimmer

Deciding to transition your farm to organic is a big undertaking.  There’s a large learning curve to becoming a successful organic farmer, and transition can be a challenging and expensive endeavor.  But it’s also a huge opportunity.  Rather than trying to grow a row crop during the 36-month transition period where you’re required to use all organic inputs and methods but have to sell your crop as conventional, instead grow soil building crops that will set you up for success when you’re fully transitioned to organic. 


First, you had better decide what transitioning while building soil health means on your farm, and second you need to recognize there are many farmers that have done this successfully already.  Farmers that have the most success spend the transition building up health, microbiology, balancing soil minerals, and building soil structure.  They build the chemical, physical and biological aspects of their soil; that three legged stool that sets the farm up for success. 

When it comes to soil health, we have a lot of good understanding about minerals. We know there is a ratio between them; we know more than 20 minerals are known to be essential for crop growth; we know deficiencies or excesses are going to hurt our crop and lead to problems with diseases or insect pressure; we know deficiencies reduce crop yield and quality. It is also essential to make sure calcium levels are right and the soils are being constantly fed a good soluble source. To make minerals more available, add carbon from sources like manures, humates, and compost if it is available and fits the farm. We know the soil has a certain ability to dish out minerals if they are there and biology is taken care of. It’s also important to remember that the soil life needs minerals and so does the crop. The better the needs of the soil life are taken care of the more the minerals in the soil can become plant-available, and the less you as the farmer will need to add to the soil. When minerals are present and in a good balance, your crop is fed a balanced diet and the less plant protective compounds will need to be purchased and the fewer problems you will have. 

Once you have a plan for minerals, it’s time to look at biology.  We know we need to create an ideal home for soil life, feed them with living roots and a variety of carbon sources like manures or plow-down cover crops of different maturities. We also know they want their food on top, without a crust on the soil that limits air and water exchange. A good way to achieve this is to shallow incorporate cover crops or residues and then use minimal disturbance from tillage to create an environment where air and water are managed. 


On-Farm Intensive with Zimmer Ag

Learn about soil health in person with Gary Zimmer

The Acres U.S.A. On-Farm Intensive – starting in summer 2021 – is held in partnership with experienced farm consultants Gary Zimmer and Leilani Zimmer-Durand at their famous Otter Creek Farm near Lone Rock, Wisconsin. This two-day educational experience will help farmers, growers and land owners maximize their land’s potential. 

Learn more here!


The big secret for soil health is filling the soil with roots. Crops like brassicas, clovers, rye and other grasses provide a lot of root structure, and when they die the old dead roots become the breathing tubes — channels for new roots to follow.  It’s similar to earthworm channels where all along the edges of the channel is an area of moisture and high fertility where a lot of diverse organisms live. These are the highest fertility spots in the field, and you can create more of these high fertility zones by growing and managing more types of cover crops and having more different types of crops in your rotation.  When looking at your own farm the question is: what plants best fit your farm? What tillage practices, crop rotations, and management tools do you choose? What’s your budget to make these changes? 

Another factor in understanding soil life and how to take care of it is making sure the soil is loose and crumbly, with a chocolate-cake like texture. With tillage, “thoughtful disturbance of the land” is the best way to control air and water and manage the decay of residues. I like shallow incorporation of residues and I use a deep in-line type ripper to break up compaction if it’s needed. Ideally we wouldn’t need to use the ripper, but conditions aren’t always perfect. In wet years we still need to plant and we still need to harvest, and driving on the fields with big equipment will later require intervention to break up compaction. I also like strip tillage as a way to build good soil structure around the roots.  We can concentrate on balancing minerals in the strip, get good root development and a good crop even if the land is rented and you don’t want to spend money on soil corrections. The purpose of the strip is not only to concentrate inputs in order to maximize plant uptake, but you had better choose your inputs well and not over-salt that zone or you’ll have problems. Buffer the inputs with carbon and use high quality fertilizer. By managing the strip-till zone you don’t have to plant in hard, tight soils and in our northern climate the zone will dry out and warm up sooner in the spring. 

I know it’s always a question of how to pay the bills and make some money while transitioning to organic and building healthy soils. It’s important to have a solid plan heading toward your goals, and work toward your goals over a longer period of time, especially if your soil needs a lot of fixing. There is no one exact way to get there, but you can’t violate the principles or expect things to be different if you keep doing them the same way. You will be happy once you have healthy, mineralized soils, you just need a realistic plan to get there.

So the question is: how do you put together a working plan to address the needs of the soil and plants?  We start by taking soil tests, plant tissue tests, and making soil and plant health observations.  Choosing what to do once you have all the information you need may require help from a good consultant.  A consultant can help find the best sources of minerals, recommend amounts of minerals, and guide you on where to start and where to find the best inputs that fit your farm.  Along with helping with mineral balance in the soil, a consultant can also recommend methods for growing soil life, when to use starter, liquids and foliars, as well as when to implement tillage with a purpose.  Finding that knowledgeable consultant will be your first challenge.  Check out The Biological Farmer and Advancing Biological Farming to walk you through the basics on soil life and minerals so you know what questions to ask.

Let’s say you took soil tests and they show that you need lime, phosphorus and trace minerals, and you intend to use a lot of manure to increase soil fertility. Building soil fertility is like making a cake.  Add together the right ingredients like a blend of manure, ag lime and a trace mineral blend, mix it up, plant the cover crop cocktail mix and watch it grow and come alive. Clip the cover crop, shallow incorporate and do it again. You can also establish a perennial blend.  Do this for two growing seasons and it’s now on the road to being “fixed” and it is certifiable organic if you followed the rules.  In this situation you’re not harvesting a crop during transition but you’ve set yourself up for a bumper crop with high yields your first year as organic, and that will be a profitable crop. Not many farmers do this.  Many struggle along with weeds and unhealthy crops during transition and then their first organic crop performs poorly.It’s better to invest in soil health during transition so you have a bumper crop your first year of organic.

Let me share an example from my family’s farm in southwestern Wisconsin.  The farm is about 1,500 acres of cropland and is very hilly. There are 80 dairy cows on an all-forage diet, and the dairy herd is certified organic. For the land we have some soils fixed, some on the way, and some just starting.  We do use the transition years to mostly fix the soil, and during transition the only thing we may harvest is some rye cover crop seed. The soils are all tested before transition, and fertilizers, calcium and manure are added to build minerals and get them in a carbon/biological cycle. 

During transition a cover crop is planted each year, often a perennial cover crop that is clipped and used to build soils.  Once it’s organic we plant corn, as this is our highest return organic crop.  The year before corn is always a legume-dominant cover crop with clovers, alfalfa and high-quality grasses.  Having a high legume blend gives us much of the nitrogen we need for the following corn crop. Two major problems organic farmers face are weeds and having enough available nitrogen. The best way to get nitrogen on an organic farm is to grow it, not buy it. To get enough soluble nitrogen and other nutrients into the corn crop, we feed that soil the same way we would feed a cow giving 100 lbs of milk/day.  A high-producing cow needs a lot of highly digestible minerals, just like a high yielding corn crop needs to follow high-quality forages that are worked in when they are young and succulent. This releases a lot of soluble nutrients for the organic corn, and is how we start the rotation farming cycle. 

We have been at this since 1994 but only in the last five years have we gotten aggressive at fixing our soil.  When we had 300 cows and 600 acres the land was worked hard. We got good production but soil organic matter only slowly improved over 20 years. We can do better. The rough hill ground on our farm we pasture and have summer forages. We harvest the acres closest to home for the cows for feed. The rest of the farm is one year corn, then a cover crop and soil building year, and then back to corn. 

Cereal rye is an important part of the rotation as it is planted after corn in the fall, then come early spring when there is frozen ground we frost seed a clover/alfalfa blend. Our objective is a great clover/alfalfa stand and not having the rye lodge on the clover/alfalfa mix or choke it out. In order to keep the rye from getting too tall and lodging, we plant it thinner following corn and don’t apply any nitrogen.  Our yields are poor, only 30-40 bushels/acre, but our soils are rapidly changing and corn yields keep going up. 

After rye harvest the fields are clipped and let go until next spring when the clover/alfalfa blend is 8 to 12 inches tall. We then shallow incorporate the cover/alfalfa into the soil and then plant corn.  This is a system we like. We are working on getting the rye yields up to 50 to 60 bushels/acre with better varieties and some controlled manure and biological nitrogen application. As our rotation goes forward we have carry over of nutrients, we’re building organic matter and more nitrogen is available from the soil every year.

That’s just one way that we like to establish our rotation for biological/regenerative organic, and it fits our farm and the area very well. For your own farm, think about what you can do to grow a corn/soybean rotation while also building organic matter and soil health. The system requires another crop besides corn and beans — what best fits your farm?  Rye, wheat, or a different small grain? Is it something you can do on your farm?  If you’re growing only row crops, how can you mineralize the soils and find the best fit for cover crops to supply nutrients and build organic matter on your farm?  Can you be successful building soils during transition?  The answer is “yes,” but cover crops and other inputs will be needed.  Not only is this a unique challenge on each farm, it’s the thing we need to do for our planet, future generations, and human health.

Gary Zimmer is a farmer, author, speaker, and farm consultant.  Gary Zimmer founded Midwestern BioAg in the 1980s, and has been farming biologically and organically with his family since 1991 in southwestern Wisconsin. Gary recently started a consulting business, Zimmer Ag, with his daughter Leilani Zimmer-Durand where they offer advice to both conventional and organic farmers who want to build soil health and resilience while making a profit on their farm.