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Aussie Green Thumb – Top Gardening Tips For Everyday People

Hydrophobic soil – What is it, and how to fix it?

Water is a key element for plants to live. Without proper watering, your garden has no chance of survival. Unfortunately, in a lot of regions in Australia, the problem of hydrophobic soils occurs, which means that getting the water to where it needs to be, can be a bit of problem.  Read on to find out what hydrophobic soil means for you and how can we fix it.

First of all, what does hydrophobic soil mean? It can happen in most situations, but is mostly found in hotter areas, where the high temperature of the soil causing rapid drying out, which negatively impacts on its organic content. The main feature of the hydrophobic soil is the inability of moisture to absorb. When water falls on the soil, it runs off the surface, or simply sits there and doesn’t mix.
As organic matter (in particular native leaf litter) breaks down, waxy residues are left behind. More often than not, this isn’t a bad thing, as it either mixes through the soil harmlessly, or is broken down by fungi and other natural processes in the soil. When the waxy residue builds up and coats the soil particles though, water repellency can occur. The more soil particles coated, the less water that penetrates.
The lower the surface area of the soil aggregate (like sand, which has less surface area on the soil aggregates than say, clay) the less waxy residue required to coat it. A simple small experiment with the soil may show whether it’s hydrophobic or not. Just take some soil and pour water onto it. If it doesn’t absorb and just pools there with round edges, you’ve got a problem.

Hydrophobic soil is dangerous for your plants, because in spite of being watered properly, no water reaches the root zone, and your plants can become stressed.

If you’ve got it, how can you fix it?

Wetting agents.
The simplest way to make your soil absorb the water is using the wetting agent. These impact on the waxy residues in the same way washing detergents impact grease and fat particles in your washing up. By reducing the surface tension of the water, the moisture can more easily penetrate the soil particle and get moisture where we need it, and our plants are watered properly. Wetting agents are easly purchased from any nursery or gardening store, are really easy to use and 99% of the time will fix your problem.

Good soil health.
The best way to fix any soil issue, is to keep it happy. Healthy soil will generally not have problems like water repellency. Working a good, well aged, organic compost through your soil, watering it regularly, and keeping the microbial activity churning along will help reduce any chance of that annoying waxy residue accumulating. Making sure you have a good soil mix will also aid in allowing plenty of space between the soil pores for water to infiltrate. Hydrophobic soil isn’t great, but it’s not the end of the world. Using soil problems like this is a great excuse to give your garden a bit of love and TLC and get them back to where they need to be for healthy happy plants.

About the author: Professional horticulturalist from NSW. Be sure to follow us on Instagram as well! Aussie_green_thumb.

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