A diverse garden or wild landscape isn’t only beautiful; it’s essential for sustainable ecosystems. In contrast, monocropping, or monoculture, is planting a single crop over and over in the same place. When driving through the Midwest United States, thousands of acres of corn and wheat span as far as the eye can see. In the South, you can find mono-cropped cotton fields and cattle feedlots. In suburbia, you’ll see monoculture lawns in front of every home.
All of these landscapes share the same common theme: they lack diversity. This is alarming because diverse agricultural systems are proven to be more resilient and ecologically sustainable. Mother Nature rarely grows large landscapes of the same thing; every wild forest, grassland, desert, and valley biome is characterized by a massive diversity of native plants and animals. When we remove the diversity from our farms and gardens, we are breaking the laws of nature, which can lead to disastrous consequences.
Let’s dig into what monoculture is, why it’s problematic, and how to avoid it in your garden.
The Short Answer
Diversifying crops promotes sustainability and mimics natural ecosystems.
Monoculture is the cultivation of a single crop every season on the same piece of land. For example, a ten-acre field planted with corn every year is considered a monoculture. Also known as mono-cropping, this method of intensive agriculture can harm local plants and animals, disturb the soil, and make crops more susceptible to pests and diseases, often leading to excessive pesticide use. Monocropping poses significant environmental and economic risks.
The opposite of monoculture is a diverse natural ecosystem, such as a forest or grassland, which naturally includes hundreds of different species of plants. Farmers and gardeners can cultivate plants more sustainably by mimicking nature and planting a diversity of species in a given area.
Some people call this practice polyculture (poly=many) because it involves growing many plants in one space and changing them over the seasons, as nature intended. Common practices include agroecology, crop rotations, interplanting, companion planting, permaculture, and integrating livestock with crops.
The Long Answer
From turfgrass lawns to corn fields to timber plantations, monoculture can take on many forms of human-made ecosystems that contain mainly one plant species. This practice upsets the natural balance of biodiverse soils and ecosystems.
As we dig into the history of monoculture, notice how this practice is only about a century old and has already destroyed nearly 58 billion tons of soil in the United States alone. For comparison, farmers in China and Japan have been farming some of the same fields for over forty centuries while maintaining the health of the soil.
Although industrialization has massively increased agricultural output in the short term, it poses huge problems for land sustainability and the food security of future generations. Let’s dig into how this type of farming started, the science-backed problems with monoculture, and how to diversify your garden or landscape for more resilience.
Modern Monoculture and the Green Revolution
Monoculture, born from modern agriculture, faces ecological and economic challenges.
The hallmark of 20th and 21st-century modern industrial American agriculture is monoculture, though its application has spread globally. Growing huge stands of the same plant makes it easier for large-scale tractors to plant, spray, and harvest crops. Monocropping is closely correlated with heavy tillage, genetically modified seeds, and chemical use. It is most common in commodity crops like corn, wheat, and cotton. However, the term can be used in any setting where humans have wiped out a natural landscape in order to plant just one or a few species.
This practice is a modern invention fueled by the Industrial Revolution and the subsequent industrialization of agriculture. The so-called “Green Revolution” (1945-1985) refers to the expansion of intensive agriculture using synthetic fertilizers, large-scale machinery, and genetically engineered seeds, among other modern technologies.
Although these concepts initially led to a huge boost in food production and crop productivity, the results of the Green Revolution were far from “green.” Widespread pesticide use, ecological destruction, soil degradation, and environmental disasters ensued. Moreover, when you plant the same thing in the same place year after year, yields decline, and soil health plummets. This means farmers face intensifying economic pressures and crop loss after monocropping for several years or decades.
Diversity in Ancient Agricultural Systems
Modern monoculture accelerates landscape degradation and soil erosion.
In contrast to the modern homogeneous fields, ancient civilizations predominately used diverse agricultural plantings. They incorporated trees, shrubs, annual vegetables, and animals into one space for more productivity and a vibrant food supply. Farmers and gardeners rarely relied on just one or two crops to fund their livelihood and feed their families. Instead, they prioritized diversity in their gardens to ensure an abundance of food.
For example, Incan terrace farms, Chinese rice-fish-duck aquaculture, Moroccan food forests, and Mayan milpas (also known as “the three sisters” of corn, beans, and squash) all incorporated a diversity of crops and livestock into one space. These agricultural systems withstood the test of thousands of years, and many soils are still producing food today.
In contrast, modern monoculture rapidly degrades a landscape. For example, monocropping, tilling, and the heavy use of chemical fertilizers and pesticides have already degraded thousands of acres across the Midwestern U.S. in just a hundred years. Studies show that soil is eroding and degrading at a rate 10 to 1,000 times faster than it was before the Industrial Revolution.
Problems with Monoculture
If you can’t tell by now, the problems with monocropping affect biodiversity, soil health, native ecosystems, food supply, and economic livelihoods of farmers. In a garden, the biggest problems you will find are pest and disease issues associated with planting large beds with the same crop over and over. While this may seem more efficient, here’s why the lack of diversity in monocrops can cause major problems for growers.
Major Losses in Biodiversity (Above and Below Ground)
Rich biodiversity enhances ecosystem resilience and sustainability.
Biodiversity describes the amount of different species in an ecosystem. In the natural world, biodiversity is resilience. More plant, animal, and microbial species richness means a more productive, efficient, and sustainable ecosystem. All farms and gardens are technically their own ecosystems. When diversity is reduced, the whole system becomes more vulnerable to losses.
Orchard Example
Diverse apple orchards thrive, resilient to pests and diseases.
For example, an apple orchard growing only one variety of apples could easily be devastated by a late frost or an aggressive tree disease. But if there were dozens of different varieties of apples planted together, there is a far better chance that the orchard would survive to produce fruits. Each variety of tree would flower at a different time and have different genetics to resist the attack of a pest or pathogen.
Vegetable Example
Diverse crop rotations safeguard against soil-borne diseases.
This same concept applies below ground. If a vegetable garden bed is planted with the same variety of broccoli in the same place every year, the potential for root-borne diseases increases dramatically. The lack of diversity in the crop bed makes it easy for problems to arise because it disrupts the soil ecology. Less diversity in plant roots means less diversity of beneficial bacteria and fungi in the soil below. These “good guy” microbes naturally protect plants from infections. When their diversity decreases, it is easier for “bad guy” microbes to take hold.
For example, broccoli and its cole-crop relatives are susceptible to a destructive disease called clubroot. It infects the roots of brassicas, causing them to become swollen and distorted. Diseased plants turn yellow and stunted and eventually die. This fungus can live in the soil for over ten years, so the monocropping of brassicas exacerbates the problem, sometimes causing cabbage or kale farmers to abandon a field completely.
The fungus has no other hosts, so it can easily infect new plants because they are repeatedly being planted in the same place in large groups. The soil loses its diverse microbiome because no new plant species are growing in the ecosystem.
Forest Example
Diversity across space and time ensures ecosystem resilience.
Notice how diversity is important across space and time. A monoculture involves planting the same thing in the same place over and over. But a natural ecosystem like a forest is constantly changing. As you walk through a natural forest, you can see dozens or even a hundred different types of plants. The species of annual plants differ slightly over the seasons as different seeds germinate and grow. The perennial plants grow with their own seasonal cycles.
However, if that wild forest is cut down and replanted as a timber plantation, the diversity is reduced across both space and time. For example, only a single species of pine trees would replace the native forest, and those same trees would grow year after year without any new diversity.
Devastating diseases like pine wilt can rapidly spread from tree to tree because there are no other species to interrupt the monoculture. This phenomenon is found in monocultures of nearly every type because large groupings of one thing make an easy target for a pest or disease.
Monocultures are More Susceptible to Pests and Diseases
Diverse crops deter pests and ensure food security.
Clearly, there is a correlation between monocropping and plant infestations. Scientists have known for a long time that monocultures increase pest and disease problems in crops. Fortunately, studies show that increasing diversity can reverse this trend.
Consider an insect with a very specific host, such as a tomato hornworm. In its adult form, the hornworm is known as a five-spotted hawk moth. These pests specifically target tomatoes and other close relatives like tobacco, peppers, and eggplant.
How Monocultures Encourage Pests
Imagine you are a five-spotted hawk moth flying through the air, searching for a plant to eat and lay eggs on. It would be a lot easier to find a huge field of tomatoes because the smell and visual cues are much stronger when many of the same plant are growing close together. A monocrop field of tomatoes is like a big sign saying, “Look! There’s lots of hornworm food over here!”
In contrast, a specific pest like the hawk moth would have a lot more trouble finding tomatoes that are interspersed with unrelated plants such as basil or cucumbers. In one study, intercropping (growing multiple crop species together) was shown to dramatically decrease hornworm pressure compared to a monocrop of tomatoes. The host plant is harder for the pest to find and the reproductive cycles are interrupted by the diversity of other plants in the vicinity.
When you compound this concept across an entire garden or farm, you can quickly see the benefits of diverse crops to disguise, deter, and protect plants from pest or disease attacks. Even more notably, a giant field or garden with only one type of plant may lead to a total yield loss. If you are growing multiple varieties and species of crops, you have lots of backups to harvest from if you lose one type of plant to pests or diseases. This creates more food security and diversity on your plate.
Reliance on Large Machinery and Synthetic Chemicals
Monocultures rely heavily on synthetic chemicals, harming soil and water.
With so much vulnerability to pest and disease infestations, it’s no surprise that monocultures are chemical-intensive. This form of growing ultimately relies on massive amounts of machinery and synthetic agricultural chemicals like nitrate fertilizers and toxic pesticides.
In the post-World War II era, remnants of wartime technology were transferred into the agricultural realm. John Deere had turned to manufacturing military tractors and tanks. These concepts were adapted into large-scale farm machinery to grow hundreds of thousands of acres of monoculture crops like corn, wheat, and cotton.
Similarly, explosive manufacturing plants turned to producing fertilizers after the war. The Haber-Bosch process was initially developed in WWI in Germany to produce the first nitrogen bomb. The process uses hydrogen and nitrogen to create synthetic ammonia (nitric acid), the key ingredient in many synthetic fertilizers.
Since the very beginnings of agriculture approximately 12,000 years ago, humans have relied exclusively on organic fertility from the Earth. The source of plant nutrients has always come from dead and decomposing plant or animal waste, such as manure, rotten leaves, or other forms of compost. These are the same organic fertilizers most modern gardeners use in their gardens!
Unfortunately, the move away from organic plant nutrients has had detrimental effects on the soil and ecology of agricultural areas. The industrialization of agriculture marks the first time in the history of humanity that synthetic (lab-made) nitrogen was applied to the land to grow monoculture crops.
As these synthetic fertilizers flow into the soil and groundwater, they pollute massive bodies of water. For example, the Dead Zone in the Gulf of Mexico is caused by fertilizer runoff from the Midwest and Mississippi River basin.
Monoculture vs. Polyculture
Polyculture offers diverse, resilient, and sustainable agricultural solutions.
Now that you have a solid understanding of the problems with monoculture, let’s explore the alternative: polyculture! Mono means “one” and poly means “many.” Polyculture means cultivating many species of crops in the same space.
Every natural ecosystem on Earth is technically a polyculture because there are many different plant and animal species growing in the same place as part of a dynamic, complex food web. Research clearly shows that polyculture is ecologically and economically superior.
Polycultures are:
- More biodiverse
- More resilient to pests and diseases
- More resilient in extreme weather, such as drought
- Less reliant on chemical inputs
- Less reliant on large machinery
- More supportive of healthy soil
- Better for local wildlife and pollinators
- More economically viable for small-scale growers
Global scientists overwhelmingly agree that polyculture is crucial for sustainable development and food security in the future. The environmental problems with monoculture simply will not withstand the tests of time and pose too many risks to our food, soil, water, and ecology.
6 Ways to Diversify Your Garden for More Resilience
It’s pretty obvious that we should aim to grow more polyculture gardens! Here are some ways to diversify your garden and make it more resilient against stressors like pests, diseases, drought, and extreme weather.
Practice Interplanting and Companion Planting
Interplanting and companion planting maximize garden space and productivity synergistically.
The practice of interplanting involves growing multiple plant species in the same bed to maximize space and productivity. Companion planting is a related concept that involves using specific plants to enhance the growth of a neighboring crop. For example:
- Leguminous plants like peas can work with symbiotic bacteria to fix nitrogen in the soil, making it more fertile for heavy-feeder crops like cabbage.
- White alyssum can attract beneficial insects like ladybugs and lacewings, which eat crop pests like aphids.
- Marigolds release compounds in their roots that deter root-knot nematodes from neighboring tomatoes.
Other types of interplanting simply maximize open space to improve diversity in your garden. Why leave any soil bare when you could use it to cultivate more food!?
Great crop combos include:
- Growing lettuce in the dappled shade of tomatoes
- Interplanting green onions alongside salad greens
- Allowing squash to vine under sunflowers
- Planting spinach in rows beneath trellised peas
As you dig into the world of interplanting and companion planting, be sure to research which plant combos are detrimental as well. Some plants make great neighbors, while others can inhibit each others’ growth. Experimentation and observation are essential for success. Always be sure that neighboring crops have enough spacing between them to reach their full potential.
Plant a Lawn Alternative
Replace high-maintenance lawns with diverse, low-maintenance alternatives for sustainability.
Lawns are the most common type of monoculture in suburban and urban areas. Most turfgrass lawns are extremely water-intensive and high-maintenance. They require constant mowing, fertilization, herbicide spraying, and troubleshooting. This isn’t only annoying for the homeowner, but it negatively harms local wildlife because there are less pollinator resources or habitat for native birds and bugs.
You can mix different species together to support pollinators and allow different plants to thrive at different parts of the season or in areas of your yard with differing sun exposures.
Use Crop Rotation
Rotate crops yearly among diverse plant families for healthier harvests.
Add diversity over time by practicing crop rotation. This means you plant different plant families in your vegetable beds every year. Crop rotations don’t need to be complicated; they only require a basic knowledge of which plants are related to each other.
The most common garden plant families are:
- Nightshades (Solanaceae): Tomatoes, peppers, eggplants, tobacco, and potatoes
- Cucurbits or Squash Family (Cucurbitaceae): Cucumbers, melons, pumpkins, zucchini, and winter squash
- Legumes (Fabaceae): Green beans, snap peas, shelling beans and peas, peanuts, and lentils
- Cole Crops (Brassicaceae): Broccoli, cauliflower, cabbage, Brussels sprouts, radishes, turnips, kale, collards, and mustards
- Onion or Lily Family (Amaryllodaceae): Onions, leeks, shallots, garlic, and chives
- Beet Family (Chenopodiaceae): Beets, chard, quinoa, and spinach
- Daisy Family (Asteraceae): Lettuce, artichoke, chicory, burdock, and sunchokes
If you plant a crop from one plant family this season, aim to grow different plant families in that bed the following season. This will dramatically reduce issues with pests and diseases. It will also nurture soil fertility and biodiversity, especially if you include legumes in your rotations.
Try Forest Gardening or a Wildflower Prairie Garden
Transform your space with native perennial forest or prairie gardens.
One of the best ways to add a lot of native diversity to your area is to plant a perennial forest garden or prairie garden. These ancient gardening methods are the most closely linked to wild local ecosystems. The key is to prioritize regional native plants.
In a forest garden, this could include native tree species interspersed with fruit trees and an understory of berries or native herbaceous shrubs. For a meadow garden, you can purchase regional native wildflower blends that can naturalize and proliferate.
This type of polyculture is best for wide open back fields, side yards, or less-cultivated areas on the borders of your property. Wildflower gardens work especially well when planted on the margins of a vegetable garden because pollinators and beneficial wildlife can provide benefits to your veggie crops.
Plant Native Species
Choose natives for low-maintenance beauty and wildlife support.
Native plants are species that are endemic or wild in your region. These plants have evolved for thousands of years to thrive in the exact soil, weather, and local conditions. They need very little maintenance once established and mostly take care of themselves.
Native plants are the most beneficial for local wildlife, like bees, butterflies, and birds. The key is to find a quality native plant nursery or search online for regionally-specific varieties. Remember, just because a plant is native to the U.S. does not mean it naturally grows in your region. Desert gardeners should prioritize desert plants, while northern growers can choose temperate cold-adapted native species.
Use Organic Fertilizers
Boost soil health with organic fertilizers for resilient crops.
Organic fertilizers are scientifically proven to boost soil biodiversity, whereas synthetic fertilizers reduce diversity and kill soil microorganisms. If you want to avoid monoculture and promote a stronger soil microbiome, choose organic fertilizers.
Organic slow-release fertilizers include:
- Compost
- Feather meal
- Fish emulsion
- Bone meal
- Blood meal
- Kelp
- Vermicompost
- Aged manure
These fertilizers promote healthy soil rather than harm it. They also improve the resilience of your garden by acting like an external immune system and digestive system for your plant.
A greater diversity of soil bacteria and fungi yields stronger crops that are less likely to succumb to pests and diseases. Better yet, organic fertilizers are safer to apply and provide long-lasting soil fertility that compounds over time.
Final Thoughts
Ultimately, monoculture is going against nature because it involves planting large amounts of the same thing over and over again. Monoculture is the core component of modern industrial agriculture and is linked to many problems with soil degradation, water pollution, chemical use, and widespread loss of biodiversity.
Polyculture is the more sustainable, ecological, and time-tested way to grow food. Create a polyculture by boosting your garden’s diversity with companion planting, crop rotations, food forests, prairie gardens, and organic fertilizers.
