How is Over Irrigation Damaging to Soil? See if It’s Safe!

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Your garden needs water and surely there’s more harm in underwatering than overwatering, right? The purpose of irrigation, however, is to strike the right balance so that your plants grow and the soil thrives. Here are a few reasons why you want to avoid over-irrigation.  

How is over-irrigation damaging to soil: When you set up an irrigation system, it’s important to schedule it so that the right amount of water is used. If not, your soil can become oversaturated and the run-off can move important chemicals out of your soil. It can also cause lower areas to have more concentrated amounts of salt minerals. As for the greater environment, over-irrigation can lead to the depletion of groundwater as well as polluted water reservoirs.  

How Does Over-Irrigation Damage Soil?  

Erodes topsoil  

Essentially the top layer of soil, topsoil is about 4 to 10 inches deep and can make or break your crops. If your topsoil is rich and full of nutrients, your plants will thrive. If not, the opposite will occur.

When there is too much water in the soil, the water will actually help the dirt move to other areas. This can include parts of your garden where there are no crops, pathways, and even drainage systems.

While the erosion of topsoil can take quite a while before you notice its effects, it can really damage your crops. If this nutritious layer of soil is gone, your plants are not able to fuel themselves.

Over-irrigation with regards to soil is most keenly observed with container gardening. Containers will have holes in their bottoms to allow extra water to drain. If you see that there is a lot of muddy water that drains, and not just clear water, it means the soil is slowly exiting your container and thus you soon will not have enough dirt for your plants.

While you can certainly replace your soil, which you will have to do if there is not enough, this is an expensive process as good, nutritious soil can be expensive on a large scale.  

Moves salts around  

With your soil are many different minerals, including salts. In balance, mineral salts are an important aspect of the growth of plants. Too much salt, however, can lead to a loss of growth.

Water will always flow downhill and if the soil goes with the water, then areas that are in low land will have a concentration of mineral salts. The roots of your plants can quickly become damaged with too many mineral salts and it will be hard to encourage new growth.  

Change in pH levels  

There is a lot happening within the soil and one important aspect is the pH level. This is a measurement of how alkaline or how acidic your soil is.

While you want to have soil that is around neutral or slightly acidic, different plants have different requirements and an expert gardener will adjust the chemical nature of their soil for different crops.

Too much water in these areas will move the nutrients around, thus upsetting the pH levels you have worked so hard to create. As a result, plants that were once thriving with low acidic soil may now have to grow in high acidic soil.  

Removes pockets of air from soil  

Yes, your soil actually needs air in it. While obviously, these aren’t large pockets, some air is needed to create light and fluffy soil.

Water-logged soil quickly becomes dense. You will be able to notice the change right away as the soil is hard-packed.

The result is that it is very hard for plants to grow and stretch their roots out. This is especially a concern when you have new plants with small roots.

Roots need access to oxygen and if there is none in the soil, then they won’t be able to breathe. Your whole plant can quickly become weakened.  

Damage to water reservoirs  

You might think that your farm or garden is the end source of your irrigation but that water has a long way to go before it stops moving. In most cases, the water run-off from your area will eventually lead to a water reservoir that is used for drinking water, both by humans and animals.

The more water run-off there is, the more it will pick up minerals, pesticides, and harmful chemicals. While as humans we can cycle out these contaminants, animals that live in lakes and ponds, or those who drink from them, will be affected.  

Depletion in underground water  

Water on large-scale crops has to come from somewhere and to save on water costs, many farmers end up using underground water sources. While these may naturally replenish themselves, if there are multiple drought years, the water may never come back, thus offsetting the natural balance of the earth.        

How to Prevent Over-Irrigation?  

While may seem rather simple, the best way to prevent over-irrigation is by not watering your plants as much. However, there is a bit of a science, especially if you are growing multiple different crops.

What you want to look for is knowing the available water storage in a plant’s active root zone. This area will grow as the season progresses, as it will start out smaller in size with seedlings but then become larger as the plants grow.

The basic understanding is that you want to water as much as the roots can absorb but not more or else that water will simply pool both in the soil and on top of it. Another option is to change your irrigation schedule.

Instead of really long periods of water spread out, you can change to shorter time sets more often. It might seem like more work if you have to constantly turn your irrigation system on and off but if you invest in a simple timer to help you out, then it shouldn’t be an issue.  


Water is important for your crops but over-irrigation can cause a lot of damage. Try to water only what you need to in order to keep the balance of your soil and the earth.  

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