Have you smelt the beautifully fresh smell of rain? It’s earthy, clean and just cant be captured in a can.
The recent showers on our dry gardens, have given us the gift of that smell again. The rich and fresh smell of soil after rain, was first given the name Petrichor by Australian scientists. Petrichor is related to actinomycetes in the soil that secrete a substance called Geosmin. Rain and its associated ozone particles, fall to the soil and release the earthy, clean and fresh scent into the air.
We humans can detect it at less than 5 parts per trillion. So next time you can smell rain in the air, it may well be the Petrichor smell wafting on the breeze from an area nearby that has had a shower of rain. And yes, it may well be coming your way. (Take the washing in).
If your soil doesn’t have the smell of petrichor, should it?
Those actinomycetes I mentioned earlier, are a keystone microbe in the soil that contribute to healthy soil. They breakdown organic molecules to contribute to healthy soils and they fix nitrogen in the soil from rainfall even without nitrogen fixing bacteria on roots of legumes.
These amazing microscopic organisms promote healthy plant growth, secrete antimicrobial enzymes and help to increase soil fertility.
So yes, our gardens can all benefit from healthy populations of actinomycetes, but how do we increase the population on our soil?
- They prefer soil with neutral or slightly acidic pH. Highly acid or alkaline soils are not happy places for these organisms, so work on adjusting your soil pH
- Green manures* and plant residues such as mulch on the soil surface will provide food sources for actinomycetes populations. Organic soil cover also keeps the soil cooler and it a better environment for the organisms to grow.
- And ensure the soil is moist to support the growth of actinomycetes.
*(Green manure crops to plant from seed now for winter include peas, fenugreek, oats, BQ mulch, mustard and broad beans (pictured). Choose one or two for your garden and sow the seeds now.)
