The hot Australian climate and unreliable rainfall can cause havoc with our soil, including
Hydrophobic soil. This condition occurs when a waxy residue builds up on the soil particles, resulting in it repelling water rather than absorbing it.
The problem is most common in sandy soils and dried out potting mix and soils containing unrotted organic matter.
You can easily identify hydrophobic soil simply by watering it. If water runs off or pools on the surface leaving the soil underneath dry, you’ve got Hydrophobic soil.
Luckily, it is not too hard to fix, here are a few common ways you can make your soil water-loving, or ‘hydrophilic’.
Soil wetting agents are a great quick fix, although not a long term solution. They work by breaking down waxy residues and breaking the surface tension in the water, making it easier to penetrate the soil.
Commercial wetting agents are available at garden centres, or you can make one at home using agar (see the Mr Fothergill’s website for details). You can also use diluted dishwashing detergent as a soil wetter, but be sure to use environmentally friendly options and check their suitability for your plants.
Improving the Soil
A long-term way to improve your soil is to add well-rotted organic matter, then mulching
over the top. This will help prevent the soil from drying out, introduce microorganisms to your soil which will break down the waxy residues and also improve your soil biology. When using mulches, be wary of continuously using pine bark or eucalypt woodchip mulches.
Varying the mulch type at each application is best. Note that more is not always better – a three to five-centimetre layer is ideal.
Plants in pots need special treatment. You can hydrate pot plant soil by soaking the pot in a
tub of water for at least 10 to 20 minutes. Adding half-strength liquid fertiliser to the water will also help replenish nutrients in the soil. When repotting plants, add fresh potting mix to boost moisture levels and provide fresh nutrients. Water crystals can also boost the soil
water retention capacity. Prevention is always better than cure with pot plants as they can
fail quickly in hot weather, so it’s a good idea when buying potting mix to choose one containing granular fertiliser and a wetting agent. This may be more costly at the outset
but may save your expensive plant while you aren’t watching.
For more information visit Mr Fothergill’s