Reasons Why Cactus Soil Does Not Absorb Water

Why Cactus Soil Does Not Absorb Water

First is when you realize top-watering your plants doesn’t work because the soil cannot absorb water. There are 2 main reasons for this: either your soil is hydrophobic or your cacti are root-bound. 

The water stays on the surface for a long time, then somewhere on the side, it finds a drain, rinses and all this water drains into the pan, without wetting the soil near the plants.

 It happens that your potting soils dry out so much that the water no longer passes, in this case, put the potting soil in water so that “mop up” well and then ensure that your soil dries between waterings.

Immersed the pots concerned in a basin so that the substrate got wet.

What is Hydrophobic Soil?

Hydrophobic soil has a super low water retention capacity because its particles repel water. Hydrophobic soil is most commonly found in places that have gone up in a fire or hot air such as topsoil located near forests whose organic matter has been released into the atmosphere.

When the compounds are dispersed, they are primarily coated with sandy soil particles close to the surface of the soil’s upper layers,  which makes the soil hydrophobic.

Why Does My Soil Not Absorbing Water?

The underlying cause of hydrophobic (water-repellent) soil is usually the presence of a chemical or physical soil disturbance, such as soil compaction and low aeration.  This often results in an impermeable layer at the soil surface that restricts rooting, forcing water to run off the soil surface instead of being absorbed. 

One of the most frustrating things to happen to a gardener is when hydrophobic soil has built up inside the garden. It’s easy to recognize it by sprinkling water on the area. A lot of people wonder how it happens. The truth is that hydrophobic soils most commonly occur in sandy soils, potting soil, and soil that contains unrotted organic matter. These particles form a waxy residue resulting in it repelling water rather than absorbing it as it should.

Heavy applications of fertilizer can cause this condition. 

Water enters the soil through the process of percolation and by capillary action. Percolation happens when water from the topsoil flows through the pores of the soil and eventually makes its way to the lower layers. This process is dependent on the soil texture, i.e. the size of the pores of the soil, soil structure, and nature of the pore space. 

How Do You Fix Water Resistant Soil?

Use a wetting agent

 Wetting agents or surfactants ( for sale here ) are the quickest and easiest way to fix hydrophobic soils.

Sprinkle/drip watering technique

Drip irrigation is sometimes called trickle irrigation and involves dripping water onto the soil over a long period of time at very low rates (2-20 liters/hour) from a system of small diameter plastic pipes fitted with outlets called emitters and monitored by on-site sensors.

Mulching and covering

A material, such as straw or bark, is spread over the ground in order to protect the roots of plants from heat or cold. It helps retain moisture and keep weeds at bay.

Tilling or mixing soil with water

You can increase the porosity of your garden by using a tiller. This will create good drainage and allow the gardener (if they’re so inclined) to add additives to the soil such as compost, leaf litter, or other organic materials.

The process of turning the soil allows oxygen to reach the soil for root uptake, and also to assist aerobic bacteria in their composting process.

Mixing in organic matter

The addition of organic matter helps improve soils with clay, or the sand. Soils with high levels of OM retain more water and have a spongy structure that resists compaction in soil, and are the nutrients in a reservoir that release slowly as time passes. OM enhances soil aeration water drainage, root growth as well as biological activities.

Wide-row and swale methods

Water is allowed to stay on the surface of the soil until it infiltrates.

Bottom watering (for pots)

If you’re interested in giving the bottom-watering method a go it’s really easy. Fill an empty bowl or saucer with ambient temperature water and add fertilizer in case you need to. From there, you can just place the plant in the container and allow it to sit for 15 to 20 minutes. (Larger pots may need longer!)

Submerging the pot in water

The best way to water a container plant is to immerse the entire pot in a basin that’s filled with water. Allow it to mop up for about ten minutes until it has absorbed all of the liquid, then empty out the excess water so that the soil can have time to dry between waterings.

How do You Increase Water Absorption in Soil?

Probably the best way to improve your water penetration in the soil is by using a fine layer of compost or horticultural mulch over the root area of your plants whenever you can and possibly throughout several seasons as well!

Another great way to improve water penetration in the soil is by adding organic matter. Coarse organic matter separates the clay particles, creating pores for the passage of water. Organic fertilizer stimulates the soil, brings it to life, and improves its longevity – nutrients, air, water, and all.

At the start of your growing season, use a tiller to work about 3 inches of organic matter into the top 8 inches of soil.

What are the Factors Affecting Water Absorption?

Factors affecting the absorption of water are:

Available Soil Water.

A sufficient amount of water should be present in the soil in a form that can easily be absorbed by the plants. The majority of water held by the plant is in the intercellular space between cells and in the symplasm of cells.

Soil Air.

The absorption of water is diminished in soils with poor aeration because of the lack of O2 and, consequently, carbon dioxide accumulation can hinder metabolic processes such as the respiration process in roots.

Good soil structure and drainage are important for good aeration. Coarse-textured soils have greater surface area than fine-textured soils, so they provide more space for air movement within the soil. 

Soil Temperature.

Temperature plays an important role when it comes to water absorption in the soil. Soil temperature ranges from 30-45°C are considered optimal habitats for water absorption. At 5°C outside, there are icy conditions that can lead to water not being absorbed by the soil but rather freezing on contact, which makes watering useless.  This is because at low temperatures,

  •  The viscosity of water and protoplasm is increased
  •  Permeability of cell membrane is decreased
  •  The metabolic activity of root cells is decreased.
  • Root growth and elongation of roots are checked.
  • Transpiration.

The rate at which water vapor is released from the leaves of a plant is known as transpiration. The amount of water vapor that is being released from the leaves is what keeps the plant cool. However, this process is not instantaneous, and it takes a while for the water to be released into the atmosphere. The plant roots are able to sense how much water has been lost by measuring how much pressure they are receiving from their root cells.

As the pressure increases due to a greater rate of transpiration, it helps promote an adaptive response in the roots that helps facilitate the entry of water into the plants’ tissues. This allows them to be more efficient in their ability to acquire water.

Absorbing Root Systems.

The number of root hairs accounts for the entry of water into the plant system. 


The metabolism or rate of respiration and absorption are closely related. Factors like poor aeration, anesthetics, and potassium cyanide inhibit the rate of respiration.

Why Does Water Stay on Top of Soil?

Water will sit and pool on top of the soil because the surface tension of the soil is greater than that of the water that is being applied to it

Water sitting on top of the soil is a problem in many areas and can lead to poor plant health, structure, and aesthetics. Factors that affect water retention by soil include:

Soil composition: The amount of clay (which retains water), amount of sand (which drains well), and organic matter (which helps with structure) can all affect how much water will sit on top of the soil.

Compaction: Soil compaction can be an issue if heavy equipment is used. This leads to uneven water penetration.

-Dryness: Dry, compacted soils are more prone to evaporation and thus cannot retain moisture as well.  When the soil is allowed to dry for some time the surface tension increases, preventing water from being absorbed.

-Drainage ability: Soils with good drainage will hold less water than those that do not. Clay and sandy soils have better drainage properties than loamy or silt loam soils. 

Bad drainage will lead to waterlogging as water becomes suspended within the soil and is not allowed to drain freely.

Peat Moss: Peat substrate, however, when it is dry, will tend to repel water rather than absorb it, as it is known for.

In Conclusion

When your soil dries out completely, it won’t absorb water anymore. This can happen when you’re trying to water plants that are especially thirsty or when the weather is very hot and dry. To solve this problem, put the potting soil in water for about an hour until it soaks up plenty of moisture, then remove the potting soil from the water and let it dry out a little bit before you water it again.

Hydrophobic soils are a nuisance, but simple and inexpensive wetting agents are the best way to resolve your problem.

Temperature and water absorption go hand in hand, but what exactly is soil temperature? Soil temperature ranges from 30-45°C (86-113°F) are considered optimal habitats for water absorption.

Droplets of water will sit and pool on top of the soil because the surface tension between that of the soil and water.

Anwar Hossain

My name is Anwar Hossain. I am a cactus lover, researcher, and cactus blogger.

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