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.
Here are 5 ways to prevent soil compaction in your garden:
- Add a drainage or irrigation system
- Prevent foot traffic on your garden
- Add organic matter to your soil
- Consider no-till gardening
- Don’t work wet soil
Below, I discuss these strategies more in detail and share some tips and product recommendations to help you prevent soil compaction in your garden. But first, what is soil compaction, why is it not good, and what are 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 the soil. 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.
Soil can become compacted for several reasons:
- Natural processes. Over time, the forces of nature such as gravity, water movement, and seasonal freeze-thaw cycles can cause soil to compact.
- Human activities. 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.
- Irrigation and rainfall. When soil is wet, it’s more prone to compaction. The impact of raindrops or irrigation can break down soil aggregates, and the weight of water can also cause compaction.
Compacted soil can have a number of negative impacts, including reduced water infiltration and storage, decreased root growth, and lowered soil fertility.
Here are some signs that your soil may be compacted:
- Poor plant growth. If plants in an area are not growing as well as expected, it could 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.
- Hard surface. 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 soil, can be used to measure the level of compaction.
- Poor root development and stunted growth. If the roots of plants are shallow, or if they show signs of being stunted or growing sideways, it could be a sign that the soil is compacted.
- Soil structure. Compacted soil often has a platy or massive structure, which means it lacks the granular or blocky structure of healthy soil.
Additionally, 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. Add a Drainage or 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 them.
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. 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 installing a drainage system in your garden and being extra cautious about how often you water your plants and how much water you give them. Whether you’re practicing container gardening or in-ground gardening, you can install a drainage or irrigation system.
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. And while you should cover the hole to prevent the soil from washing out, the material you use shouldn’t block excess water from getting out. Plastic mesh and large irregular pebbles 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 and trench drains.
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:
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 waterlogged and consequently compact soil once the planting season begins. Picking a good garden spot might also save you the cost of installing a drainage system.
2. Prevent Foot Traffic on 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 desire 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.
Additionally, you can 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.
In the YouTube video below, Richard Fusinski shows how he protects his vegetable garden from critters using CDs:
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.
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 the 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 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. 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 accelerating the decomposition of organic matter.
As I explained earlier, organic matter binds microaggregates and macroaggregates in your garden soil, keeping it from compacting.
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 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.