Wow, this summer we had gone from hot and dry with no rainfall, to very humid- with temps hovering in the mid-thirties, to an onslaught of gale force winds from the effects and remnants of cyclone Oma, to a nice cool and comfortable 25 degrees with cloudy days and showery episodes throughout the day- (all in the last 4 weeks) but just as we start to enjoy the welcome cool change, we are hit with another sweltering week of high temps in the high- thirties but- autumn at last- it is!
Unfortunately, the rainfall we received to date as I write this column, has not been significant enough to hydrate our soils sufficiently, which soon became evident after I scraped back some mulch layers around the place and dug into the dry topsoil. Which is why having a good open mulch that allows rainfall to percolate down through to the soil level (when we do get it) where the plant roots are, is so important indeed. I have mentioned a few times about the perils of plastic weed matt layers on the soil surface and I will recap quickly- my reasoning; we have mostly sandy soils here on our Bribie island and local districts, and lots of these soils are also hydrophobic (water repellent and hard to wet) and if we want to convert our sandy- hydrophobic soil to a more fertile soil that will hold more moisture, then we need to either add compost, composted manures or organic mulch layers to the soil and apply irrigation to activate the soil biota (micro-organisms including earthworms) to break-down organic material (into humus) which becomes assimilated into the soil profile, providing plant available nutrients. So, when you have a plastic woven weed matt stretched across the soil surface- the first thing that becomes evident, is how can you apply organic material such as compost to the soil profile? And the benefits of mulching become only a decorative feature and not a soil building exercise, due to the fact that the organic mulches can never touch the soil surface, and when the heavy rains do arrive, it usually tends to cascade off the weed matt as quick as it had pelted down. And as a result, that vital elixir of life- has simply dissipated away.
Fortunately, there are better options when considering a weed barrier when building a new garden, such as the relatively new- weed fabric products, like ‘Weed Gunnel’, which is excellent for weed control and is able to absorb moisture while also having the benefits of breaking down overtime and is also a registered- Allowed Input (452A1)- for organic gardening. And another brand- ‘Eco-Cover’, which is organic, compostable, and biodegradable, builds the soil carbon levels, conserves water and of course; controls the weeds too. These products are widely used in the horticultural, agricultural and land management industries and are more sustainable and environmentally friendly- in comparison to the polyethylene weaved plastic weed mats, that can starve the soil from oxygen, moisture and nutrients. And unfortunately take a long time to break down and may persist in the environment for many years to come. So, if your soil is hard to wet and you are waiting for the rains to hydrate your patch? Give yourself the best possible chance, add some organic matter, whether it be compost or composted manures to the soil profile and apply some tonics- like worm juice, and a layer of mulch- that will accept applied irrigation, then you will have made a great start to enlivening your soil- while building a bank of plant available nutrients, which will assist to sustain your plants through these tough environmental challenges well into the future. The Happy Horticulturist