Soils ain’t Soils ®


by Mick O’Brien Dip.Hort (MAIH)- RH-101

Well it has been a while since I wrote an article on my -Soils ain’t Soils- topic, so I thought now with the change of the seasons and especially now that spring has arrived it would be a good time to reiterate some helpful hints on improving our soils here on Bribie Island and local districts once again before the onslaught of summer. I have mentioned previously in other articles, the importance of soil building, which is a continuous process of adding composted organic matter (compost, leaf litter, vermicompost or manures) while managing to keep adequate soil moisture in the soil profile and protecting the job lot with cover layer of mulch - whenever possible. But there are definitely challenges to overcome which may prove difficult in the landscape, as the individual landscape design and subsequent various plant choices may need different soil types or moisture requirements in comparison to the plants which are growing naturally which are endemic to the area and have adapted to the local environmental conditions. These plants have evolved over millennia to adapt and survive drought conditions in our poor sandy soils and have specialised root systems accordingly. If we were to create a rainforest garden, this type of design will obviously require more irrigation with a serious focus on actual soil improvement with the aim to establish a pioneer planting canopy which provides a microclimate underneath with filtered light and offering protection from the harsh elements. In time, this will allow for successful understorey planting with subtropical colour and delicate ferns. The same of course for when planting an orchard or vegetable garden as the more resilient your trees and crops are (hydrated with a healthy nourished root system tapped into a plethora of soil microorganisms that work in a symbiotic relationship to thrive and survive together) the more ability they will have to withstand the tough environmental hot, windy and dry conditions that may dry most plants to a cinder in summer. So it always comes back to the soil preparation and building the appropriate soil for the plant species you intend to plant.

looks good enough to roll in. The joys of being a horticulturist!

I was explaining at a demonstration at an open garden day, a few years back, that blending all the available soil building additives in the world will not bind together and form a loamy clumping soil unless there is enough moisture added to the mix to start the process. I poured some potting mix into a wheel barrow and threw in a bucket full of my own specially blended rock dusts: Fertil8-gold ® and mixed it around and grabbed a hand full of the mixed media and threw it in the air behind me - and as it all blew away on this windy morning, I went on to explain that - “without moisture, fertilisers, compost and soil microorganisms - will be of little benefit”. So we need to keep the soil moist in the beginning to encourage the plants roots to take up the space. The trick is to keep the balance in check and provide the right soil requirements for your intending planting needs and mulch to conserve water. Also make sure your mulch allows moisture to penetrate through to the soil profile as these plants may exist in these conditions - but not thrive. Naturally occurring endemic species such as Grevillea and Banksia or Lomandra species tend to thrive on neglect, are drought tolerant and bring in the local wild life. But our Kangaroos love our special tasty succulent - non endemic landscape plants, it’s like pavlova to them! -Your Local Happy Horticulturist!