Soil compaction is one of the most challenging and common soil issues in a garden. It can create difficulty when planting new seeds, waterlog all of your crops, or make vegetation nearly impossible to grow. If you want to ensure that your garden doesn’t succumb to compaction, you have to be proactive in preventing it.
Here are 5 ways to prevent soil compaction in your garden:
- Improve drainage and add an irrigation system.
- Prevent foot traffic in your garden.
- Add organic matter to your soil.
- Consider no-till gardening.
- Don’t work with wet soil.
Below, I’ll discuss these strategies more in detail and share some tips and product recommendations to help you prevent soil compaction in your garden. But first, I’ll explain what soil compaction is, why it isn’t good, and the signs your soil is compacted.
Understanding the Reasons and Impact of Soil Densification
Soil compaction is the increased density of soil and reduced soil porosity owing to stresses applied to it. The decrease in the number and size of the pore spaces between the soil particles impedes root growth and function as the pores transport water and air within the soil.
How Soil Becomes Compacted
Soil can become compacted for several reasons, including the following:
Over time, the forces of nature such as gravity, water movement, and seasonal freeze-thaw cycles can cause soil to compact. Periods of heavy rain can also physically push down the top soil layer and create dense crusts on the surface, reducing permeability.
Agricultural practices, such as repeated plowing and heavy machinery use, can contribute to soil compaction. Even regular foot or vehicular traffic in an area can compact the soil, especially if the soil is constantly wet.
Frequent overwatering from unregulated irrigation systems can also cause the soil to become waterlogged for extended periods.
Compacted soil can also have a number of negative impacts, including reduced water infiltration and storage, decreased root growth, and lowered soil fertility.
Signs of Compaction
Here are some signs that your soil may be compacted:
Poor Root Development and Plant Growth
If the roots of plants are shallow, or if they show signs of being stunted or growing sideways instead of deeply into the soil, it can be a sign that the soil is too compacted for the roots to penetrate.
If plants in an area are not growing as well as expected, it can also be due to soil compaction. Compacted soil can limit root growth and reduce the availability of water and nutrients, which can lead to reduced plant health and productivity.
Water Pooling or Runoff
Compacted soil has less pore space, which can decrease its ability to absorb and hold water. This can lead to water pooling on the surface or increased runoff after rainfall.
When watering the soil, observe how long it takes to absorb the water from the surface. It shouldn’t take too long to penetrate the root zone if the soil has proper drainage. Water pooling on the surface can be lost through evaporation, leaving your plant roots thirsty.
Hard Surface and Platy Structure
If the soil surface is hard and difficult to penetrate, it could be a sign of compaction. A penetrometer, a tool used to measure the force needed to penetrate the soil, can be used to measure the level of compaction.
Compacted soil often has a platy or massive structure, which means it lacks the granular or blocky structure of healthy soil.
Without many pockets for oxygen and nutrients, the survival of soil organisms is threatened. Like other soil organic matter, soil organisms play a crucial role in maintaining soil fertility, structure, drainage, water-holding capacity, and aeration.
How to Protect Soil From Compaction
The strategies discussed below will help prevent your soil from becoming compacted or even help fix soil that’s already compacted.
However, some are just quick fixes. For an effective long-term solution, you’ll need to figure out what caused the density of your garden soil to increase in the first place.
1. Improve Drainage and Install an Irrigation System
Overwatering is a common mistake, especially among beginner gardeners, and understandably so. We’re taught plants need water and sunlight to grow—and since we can’t control the sun, we sometimes get a little overzealous when watering our plants.
That said, overwatering can be a costly mistake. Not only do you waste water and money on water bills, but you also suffocate your plants, which can eventually kill them. In fact, overwatering your plants is much worse than underwatering them and has a much greater chance of causing plant death.
Overwatering your garden can result in waterlogging, where water can’t drain away fast enough. Consequently, there’s excess water in the plant’s root zone. This can lead to the rapid growth of fungi species causing root rot.
Poorly drained soils are susceptible to becoming waterlogged. And waterlogged soils, in turn, are sensitive to compaction, particularly when you put pressure on them.
Waterlogging can be prevented/controlled by improving the drainage capacity of the soil using porous soil materials or amendments, such as sand and perlite.
Alternatively, installing an efficient and well-regulated irrigation system in your garden and being extra cautious about how often and how much you water your plants can prevent keeping your soil unnecessarily waterlogged.
Whether you’re practicing container gardening or in-ground gardening, you can install a drip irrigation system. This system also reduces the force of water on the soil surface, effectively preventing compaction.
How to Ensure Good Drainage in a Container Garden
Most plant containers have drainage systems already built into them in the form of a hole at the bottom. However, some flowerpots don’t feature this hole for aesthetic purposes.
Container gardening calls for drainage because excess water will not have anywhere to go after the plant has absorbed enough water. As a result, the excess water will stagnate at the bottom of the container, putting your plant’s roots at risk of root rot.
When soil becomes saturated with water, you’ll also notice water starts to sit on top since it’s no longer taking in water. Water pooling on the surface is also a sign that your soil is hydrophobic. Another sign you’re overwatering your plant is mold on the soil.
If your plant container has no drainage hole, ensure to drill one or repot your plant in a pot with drainage holes and is made of porous material, such as an unglazed terracotta.
And while you can cover the hole to prevent the coarse soil particles from washing out every time you water the plant, the cover material you use shouldn’t block excess water from getting out. Coffee filters or mesh pads are good choices.
How to Ensure Good Drainage in an In-Ground Garden
If your in-ground garden tends to get waterlogged, be it from roof runoff water after heavy rain or overwatering on your part, your garden needs a kind of drainage system to remove standing water.
Some types of in-ground garden drainage solutions include French drains to redirect pooling rainwater or runoff away from garden plants.
Ryan, a Technology and Engineering Teacher with a passion for designing and building, shows you how to install a DIY French drain in this YouTube video:
Alternatively, you can create a raised garden bed for your crops or design a cleverly elevated flower island bed with well-draining soil. You can create a multilevel island where the most drought-tolerant flowers are on top, while the moisture-loving ones are on the lower levels.
How to Water Your Garden Effectively
If you find that you constantly overwater your plants, installing an irrigation system is the best solution. You can choose between sprinkler systems and drip irrigation. Both irrigation systems allow you to set a watering schedule, which should vary depending on soil type and season.
During summer, for instance, you should water your plants more often than during winter. Whereas garden soils with a higher water-holding capacity, such as clay soil, require less-frequent watering.
Just remember to adjust your watering schedule such that the irrigation system only waters on the assigned days each season. Doing this will ensure you don’t overwater your plants, giving them a chance to grow and thrive.
This YouTube video by Texan garden enthusiast Scott Head shows how to install a drip irrigation system:
If you prefer not to install a drainage or irrigation system yourself, you can hire professional gardeners to do it for you.
Pick the Right Spot
If you’re starting a garden, avoid soggy, poorly drained areas in your yard. This will save you the headache of dealing with a frequently waterlogged garden and consequently compacting soil once the planting season begins. Picking a good garden spot might also save you the cost of installing a drainage or irrigation system.
2. Prevent Foot Traffic in Your Garden
Foot traffic is another common cause of a compacted garden.
If you regularly hike, especially in state parks, you may have noticed how hiking trails tend to be compacted. Continuous foot traffic compacts the surface soil and creates paths, limiting vegetation growth. You may also come across desired paths resulting from trampling by humans and animals.
Preventing foot traffic—or worse, vehicle traffic—in your garden can help prevent compaction.
The following strategies will help you achieve this:
Practice Proper Plant Spacing
If you’ve planted your plants too close together, it affects how they grow and makes gardening difficult. This includes watering, weeding, or pruning. So you may find yourself regularly stepping into the gardening plot to perform these gardening tasks, which is a no-no as you risk compacting your garden soil.
If you can’t easily reach the middle of your gardening plot or get to it, consider spacing your plants further. You can also prevent soil compaction caused by foot traffic by building a designated garden path. Reducing the size of the planted areas in your yard can also work.
Consider Using Garden Beds
Using garden beds—also called garden boxes or planter boxes—can help ensure you and others don’t trample on your garden. You can choose between raised or in-ground garden beds.
You can also have paths between the beds. How wide or narrow you should make your paths depends on the frequency of usage. High-traffic walkways should be wider.
You can use loose materials like gravel, wood chips, and slate chipping as the surface of your garden paths or solid, durable materials like slabs, decking boards, and natural stone.
Put up Garden Signs
Putting up a sign discouraging people from walking through your garden can effectively help prevent foot traffic. For instance, you could have a sign that says “Please Don’t Step On The Garden” or “Don’t Walk On Me.”
Signage influences pedestrians and drivers to use alternate routes, i.e., intentionally made paths. You can make a sign yourself or buy one online.
Build a Garden Fence
If you’re dealing with animal trampling and not human trampling, signage won’t be of any help. Instead, you can put a fence around the perimeter of your garden to keep your dogs, cats, rabbits, or other pets out. Fencing will also help keep people from damaging your plants and beds.
A fence will not protect against birds and squirrels—the former fly and the latter climb. However, these critters are so light that they will barely impact your garden soil’s compaction.
That said, they can still cause damage by eating your vegetables. To keep them out of your garden, you can use a scarecrow or place reflective surfaces on structures surrounding your garden.
Use Lighter Agricultural Equipment
If you’re growing crops on a large scale, using heavy equipment to sow or harvest can cause significant soil compaction. Heavy machinery applies excessive pressure on the soil, causing it to compact. If possible, use lighter machinery or reduce the frequency of use.
3. Add Organic Matter to Your Soil
Organic matter is essential to a healthy garden for numerous reasons, including storing and supplying essential nutrients and preventing soil compaction. Organic matter holds soil aggregates together, increasing soil porosity and reducing compaction.
The two main ways to add organic matter to soil are mulching and composting.
Mulching involves laying organic or inorganic mulches on top of a soil surface. Organic mulches help retain soil moisture, add nutrients to your garden soil, and protect it and your plant roots from temperature extremes.
Organic mulch also soaks up excess water and absorbs most of the impact from rainfall, thereby preventing soil compaction. It comes in many forms including hay, straw, shredded bark, wood shavings, dried leaves, and grass clippings.
As some of these materials are readily available in your garden, it’s a low-budget option of adding organic matter to your soil. However, if you’re an urban gardener or don’t have time to make mulch, you can buy organic mulch.
Composting involves adding decomposing organic matter into the soil to fertilize the soil and help plants grow. Its crumbly texture can also improve the drainage capacity of your soil, reducing the risk of compaction.
Your compost pile can comprise food scraps, coffee grounds, dead leaves, grass clippings, newspaper, and shredded twigs and branches.
Like mulch, compost can be homemade or store-bought. Some communities also have composting programs that distribute compost locally.
4. Consider No-Till Gardening
Tilling is quickly becoming an outdated agricultural method and for good reasons. For starters, it contributes to soil compaction by initially loosening the topsoil and eventually subjecting the loose soil surface to erosion when it rains.
Moreover, walking on freshly tilled and moist soil can flatten the surface, creating a water-impermeable crust. Using heavy tilling machines can also cause the same issues.
The solution? No-till farming! This technique involves cultivating crops with minimal soil disturbance and leaving crop residue on the soil’s surface.
5. Don’t Work with Wet Soil
Working wet soil packs the soil particles tightly together, leaving less room for water and air to penetrate. In other words, it causes soil to become compact.
To determine if your garden soil is dry enough to work, squeeze a small amount in your hand. If it crumbles, you can get to work. But if it forms a muddy ball, give it a few days to dry.
Soil compaction alters soil structure, limiting water and air infiltration and causing roots not to grow deep into the soil. This, in turn, affects plant growth and reduces your garden yield.
You can prevent soil compaction in your garden by avoiding practices that apply pressure on the soil surface, such as continuous foot traffic and heavy equipment use. Adding organic matter to your soil also reduces the soil’s susceptibility to soil compaction.