Add Clay?

Sue DempsterNative Gardening2 Comments

Should you add clay to your soil?

You may be surprised at what you’ll find in your garden beds.  I know I often am!

Many times when I’m creating a yearly plan for my customers, the question comes up, ‘Should I add clay?’

In fact, early this year one of my customers was quoted close to $10,000 to add clay so that her garden beds could be ‘made ready’……$10,000!

Now I realize Perth gardens and sands are not ‘natural’ in the way they used to be before urban development, but my answer to this question is almost always NO.

I’ve made a couple of assumptions, to be clear, including that you’re looking to create a healthy, sustainable and beautiful water-wise garden or verge.  If this is correct for you, then please don’t put any clay in your garden beds.  WA native plants simply don’t need it if you plant the appropriate plant for your location.

Should you add clay to your soil? science is clear, as is my own experience, that WA plant roots’ exude what they need into the sand directly, to activate the bacteria and fungi in order for that sand to support the plant with exactly what it needs.

I can say this is true with absolute confidence, based on my experience of either planting, or supervising the installation of, more than 1 million WA plants in Perth and the South West.

When clay, or for that matter, wetting agents, fertilizer (including slow release or native fertilizers), organic material and so on, are added into our Perth sands, our local plants simply get confused.  Most of my clients initially find it challenging to plant into our Perth sand with no additives and let the plant do the work, but that is exactly what is required to have a thriving native garden.  And once the results start to show in plant health and seasonal colors, the gardeners we work with don’t look back.

If you get the right plants for your location and plant them appropriately, and directly into your Perth sand, they will thrive. Without adding anything, including clay.

If you are planning a conversion to a native garden or verge and you’d like a second opinion before you spend money on ‘changing your sand’, adding clay, or anything to do with ‘getting your garden bed ready’ …please call me.  I expect I’d be able to show you how to save money AND create a thriving native garden that you’ll love as much as the local birds and insects.

Boxed Green is a local plant advisory service in Perth, Western Australia.  We support home gardeners with plant selection, delivery and placement for all situations, advice on how to transition home gardens to local native plants and run workshops to share the knowledge and experience of 3 generations of connection to WA plants.

Go to the links for a free 15 minute phone consult with a Boxed Green local plant specialist, or a 2 hour free workshop on gardening with WA native plants, or register your e-mail and suburb to keep up to date with our latest offers here.  

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2 Comments on “Add Clay?”

  1. This is really interesting info. Curiously, do you recommend the same for newly built homes? The sand I find is building sand with building chemicals in it. Would you add some organic matter to this, thinly perhaps? Fantastic of you to share your knowledge!

    1. Hi Katie, There’s a couple of things going on here, which I’m happy to touch on. Just to reiterate, I am only referring to WA native plants in my article. If you’re planting Australian natives (from the East or Tropical locations), or exotics/fruit/edible gardens etc, none of what I’m saying would make any sense.

      So again, my answer would normally be no, don’t change what you have. Most development sites I’ve been involved in, or home gardeners I’m working with in new developments, have a similar issue. That is, due to government planning and/or building requirements the developer removes the important top-soil, and replaces it with a high clay component sand that has come from anywhere up to 5 meters deep under the topsoil (locally or imported from another region). Normally referred to as ‘cut-and-fill’ but that’s the subject of a whole blog in itself.

      This is why I say…it’s not your fault! You are dealing with a complex problem and to be sure, loading up the garden bed with nutrient (organic or chemical) first also doesn’t help.

      I have seen many new homeowners bring in loads and loads of ‘stuff’ only to end with having to deal with the yellow sand again (and many dead plants). This is why I say new thinking is required, or perhaps, connecting with the ‘Art of Gardening’ rather than the science. We often blame the plants without first considering the environment we are putting them into. The new thinking of don’t add anythying, read the stories from the plants, and respond according to what they tell you, is where we are coming from.

      WA native plants will get your garden through the difficulty of adapting from a yellow sand to a rich ecosystem over time.

      This is why plant choice is so important, and generic advice is difficult to give. I always choose plants that are what I call, ‘early adopters’ for this first phase of the transition to a healthy sand and garden bed. These early adopters (species will depend on location, gardeners intent, season of the year, etc.) are my test. They will tell the story as they develop roots and draw out the chemicals. Their story is told in the leaves (shape, color, growth rate and so on), the rate of growth, ‘droopiness’ of the new growth and many other signs of how the plant is developing when compared to the ‘norm’.

      The other ingredient to add?…….a big dose of patience!

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