Going out to water your lawn as usual and watching as the soil repels the water can cause a reasonable amount of panic. This is one of those things that seems like it should never happen but that almost inevitably will for any soil or grass type combination given enough time and the right weather.
Having a spot of hydrophobic soil isn’t a failing. It just means circumstances lined up just right to create these conditions. I’ve had to deal with hydrophobic soil in my lawn and landscaping projects at least a dozen times. With all that experience and the research I put in at the time, I’ve learned a bit about what to do to create more favorable conditions for water absorption. Below you can learn why your lawn may be hydrophobic and what you can do to fix the situation.
What Is Hydrophobic Soil?
Hydrophobic soil is soil that repels water instead of absorbing it. This is often caused by an imbalanced, dry soil composition or soil that is heavily compacted. Hydrophobic soil can always be fixed.
If you go to water your lawn and the water runs off or sits on top of the soil until it evaporates, you have hydrophobic soil. No water will reach the roots of your grass or other plants. Often, if sprinkler systems are in place, hydrophobic soil isn’t noticed until brown patches begin to develop. The sooner you act, the more likely you are to be able to save your lawn without needing to replant in spots.
How to Fix Hydrophobic Soil – The Short Answer
To fix your hydrophobic soil problem, you’ll need to do three things: aerate, amend, and hydrate. Though these steps should be done in this order, the exact items and methods you end up using will depend on your specific soil and weather conditions. You may also want to append a “repair” step at the end of the process, depending on when you managed to spot the hydrophobic conditions.
Your Lawn’s Soil Isn’t Absorbing Water – Here’s Why
What causes hydrophobic soil? Compacted soil, dry soil, hot weather, “poor” soil, soil with little organic matter mixed in, soil composition that is primarily rock or sand, soil with an inactive microbiome, lack of worms or mycorrhizae- they are all factors that can cause your soil to become hydrophobic. Below, each of these factors is explained with advice on how to recognize if this is the reason your soil repels water.
Compacted Soil
Compacted soil combined with a streak of hot or dry weather is the most common cause of dry soil that won’t absorb water. This is the easiest type of hydrophobic soil to fix, especially if that soil is under your lawn. Soil compaction can begin 6 or more inches below the surface of the soil. To test for soil compaction, use a thin metal skewer or a compaction tester. Press the tester into the soil. With steady, even pressure a thin metal tester should be able to slip 2 feet into the soil without any firm resistance.
Hot Weather
If you’ve had several weeks of temperatures of 85F or above with little or no rain, your soil may have dried out and warmed up to the point where certain compounds in the soil have created a sort of waxy film that will repel water. This is most apparent if you try to water your lawn to the point of having standing water that won’t dissipate for several hours.
Lack of Moisture
Related to the hot weather condition mentioned above, a lack of moisture over a long period can result in the soil becoming hydrophobic. Even in lower temperatures, a complete lack of water, allowing the ground to dry out for several feet, can allow for all small organisms and insect activity to die off. This often results in cracked ground. At this point, your lawn would also likely be brown.
“Poor” Soil
A lawn needs “rich” soil or soil with plenty of water, nutrients, and a thriving microbiome to stay healthy. Poor soil lacks the necessary building blocks to maintain these conditions. Sandy or silty soils are often described as poor soil types.
Coarse Soil Composition
Sandy and rocky soils can become hydrophobic easily in hot weather. These types of soils aren’t known to easily hold water in the best of times. If this is your soil type, you’ll need to get into the habit of amending the soil regularly to solve any hydrophobic issues you may be having as well as prevent future problems.
Lack of Organic Matter
A lack of organic matter in the soil can cause more than a dearth of nutrients. Organic matter that can break down over time provides your lawn with nitrogen. This organic matter also acts as a sort of sponge, holding moisture in the soil. Without enough organic matter, you can end up with soil that quickly dries out and become hydrophobic, even after aeration and the use of a wetting agent. Organic matter or “loam” is necessary if you want to build a lawn that can hold moisture.
Why You’ll Want to Fix Hydrophobic Soil ASAP
Hydrophobic soil will cause several issues in your garden that will potentially devastate your trees, plants, and lawns. In addition to the vegetation suffering, you’ll start to see the effects hydrophobic soil can have on the general environment. Here are some examples of the environmental problems hydrophobic soil can cause.
- Plant Dehydration
- Plant Starvation
- Plant Suffocation
- Standing Water
- Localized Flooding
- Water Erosion
- Insect Infestation
- Unusable Areas
Poor Microbiome
The microbiome of your lawn is the last line of defense it may have just before hydrophobic conditions set in. When heat and a lack of moisture allow certain compounds to congeal and create a dense, waxy surface, your lawn’s microbiome could be able to break this down or interrupt the process. This can allow for more time between rains or watering sessions before your lawn becomes hydrophobic. A poor microbiome typically accompanies a lack of loam, organic matter, or other health indicators like beneficial insects.
Lack of Worms or Mycorrhizae
Worms are great, natural aerators for your soil. They help break down organic matter and they won’t harm the roots of your grass like grubs or other insects that live closer to the surface. Similar to worms, mycorrhizae are “fungus roots” that can attach themselves to the roots of your grass and provide your plants with more nutrients than they would get otherwise.
This beneficial fungus has a symbiotic relationship to any plant it attaches to as a host while simultaneously improving the surrounding soil. These are both very common, helpful indicators of lawn health. Without either of them, your lawn is at greater risk of becoming and staying hydrophobic.
How to Fix Hydrophobic Soil in Lawns
Hydrophobic soil is one of those things that can cause a reasonable amount of panic, especially if you have recently seeded your lawn. At this point, water absorption is critical and hydrophobic soil can cause much more damage than it would for a completely established lawn. The good news is that the process of fixing hydrophobic soil is relatively foolproof and can help your lawn beyond providing a remedy for the hydrophobia. Below are the steps you may need to implement this hydrophobic soil fix.
0) Prep Step: Apply a Wetting Agent
Before moving on to any of the steps that will help you fix your hydrophobic soil for good, you may want to start with an action that can help improve the health of your lawn. If your lawn looks a little brown or “crispy” you should apply a wetting agent to deliver some emergency moisture. This can not only support the overall health of your lawn, but it will help your lawn recover while you follow these steps and implement this hydrophobic soil solution.
1) Aerate
The first true step that needs to be taken to fix soil that’s not absorbing water is to improve the aeration of that soil. This may seem a little counter-intuitive as aeration is also done to improve drainage but this is critical even if you aren’t having a soil compaction issue. Aeration can also help break through that waxy coating that hot weather and a long period of drought can cause.
Aeration can be done mechanically using a specialized tool or something you have on hand like a heavy rake. Lawn aeration can also be achieved by taking advantage of specialized liquid aeration products that are specially formulated for lawns. For hydrophobic lawns, I recommend a combination approach. The use of a spiked roller followed by liquid aeration can help improve your soil’s texture and general health.
2) Amend
The second step to having a lawn that can once again absorb the moisture you need it to is to amend the soil. This is key to trapping the moisture near or beneath the surface of the soil. This can be difficult to do if you have an established lawn. If this is the case, use extra-fine compost, wood chips, or another type of organic matter with a small particle size. If you are re-seeding several hydrophobic spots in your lawn, it may be worth digging compost directly into the soil before seeding.
3) Hydrate
Once you have completed the aeration step and added organic matter to the soil, it’s time to hydrate your lawn. To get things back to where they need to be, the dry soil under your lawn needs to be soaked. 2 or more inches of rain can accomplish this. If there is no rain in the forecast, water your lawn evenly for about an hour or to a depth of 2 inches. You may need to repeat this process the following day if the soil still feels dry. If your lawn still looks relatively healthy, you can stop here.
4) Repair
Often, hydrophobic soil isn’t something you notice until it’s too late and several brown spots or dead patches have already appeared in your lawn. If this is the case, it’s a good idea to use the above steps to improve the overall health of your lawn. Once this is done, you can go back over your lawn and take note of any dead patches. These patches can be cut out and plugs cut from the healthy grass can be used to fill in these sections quickly. Grass seed can also be used, but this may take longer and it needs to be the right time of year for the seed to germinate and take root.
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