I put Soil Solver to the harshest of tests in the middle of a heatwave during Perth’s hottest summer on record. So how did it perform? Read on…

How Soil Solver and Kaolin Clay Restored my Excitement in Vege Gardening

Disclaimer: I have no affiliation with Soil Solver or any other garden product, and there are no affiliate links in this article.

Ever get the feeling your vege gardening progress has stalled?

You know you’re up against it as a vege gardener if you live on Perth’s Swan Coastal Plain – you’re battling with the worst soil in the world. Not soil – sand. Ancient, grey, hydrophobic sand devoid of structure or nutrition.

You’ve done all the right things. Drawing on the collective wisdom of experts on radio and at local gardening seminars, on Gardening Australia and online, you’ve gone the ‘sustainable gardening’ route. All organic. Replaced the lawn in your back yard with raised garden beds fitted with dripline irrigation. Cultivated your beds with aged weed-free manures, compost, wetting agent. And of course, bentonite clay.

The Bentonite Clay Promise

Bentonite clay was supposed to be the game-changer. How many times have you heard the experts claim it would permanently transform your gutless grey soil into a rich, water-retaining growing medium? So how does that claim stack up against the reality?

I can only speak from my own experience, but I’ve gotta say not well. Not well at all.

I have dug countless bags of bentonite into our beds over the years. I kept the faith, waiting for that permanent transformation. To be frank, it didn’t seem to work very well even short-term. It absorbed water, sure, but clumped, refusing to properly integrate into the soil. Too many years down the track, I finally had to face facts. Bentonite clay had NOT permanently transformed our sand into rich loamy soil. I decided to stop throwing good money after bad and gave up on it. And within a year, 2 at most, the beds had defaulted to their native state – as deficient, dusty and hydrophobic as ever. So much for the permanent fix promise.

Bye Bye Bentonite, But Now What?

I continued to work manure and compost into the garden beds, and to apply wetting agent when the soil became hydrophobic – which it always had, and still did. I never regretted abandoning bentonite clay. Doing so had made virtually no difference (except to the bottom line!). We had our successes and failures in about the same proportion as ever. That was dispiriting. You expect to keep improving, not stall.

We’ve derived great joy out of our backyard mini food farm for a lot of years now, and were never going to give up. But what to do about our frustration? My partner started trying new veges and varieties, while I experimented with grow bags and self-watering pots. It was refreshing exploring like this.

For me, though, the turnaround came after subscribing to a local vege gardening site on social media (about 12 months ago now). Of course, there were the eyeroll-inducing self-appointed experts you get everywhere on SM, but some members who regularly posted pictures of their thriving organic gardens captured my attention. They were walking the walk, producing magnificent organic veges and fruit from abundantly yielding backyard oases that put our patch to shame. When these guys talked the talk, I listened.

That set me off in two new directions. The first was no-dig gardening, which I knew a bit about but had never properly investigated. We now have a small no-dig section in our backyard that is looking promising. More on that in a future post.

The second, believe it or not, was a soil treatment alternative to bentonite clay – kaolin clay. The kaolin clay product most often mentioned was Soil Solver, which is the subject of this post.

The Soil Solver Promise

Like bentonite clay, Soil Solver Clay Plus Minerals is promoted as a permanent fix for nutrition-deficient hydrophobic sandy soils.

Needless to say, after my disappointing experience with bentonite clay, I was sceptical, but I had some interest in the product based on a YouTube excerpt of a kaolin vs bentonite clay comparison conducted some years ago by Trevor Cochrane, of the Garden Gurus TV program. He had planted veges into two beds, one treated with kaolin clay (via Soil Solver), the other with bentonite clay. The plants in the Soil Solver bed had done far better. I never followed up at the time because I was tiring of laying out bucks for bag after bag of bentonite clay, and Soil Solver was more expensive still.

I would not have considered trialling Soil Solver were it not that the walking-the-walkers in my vegetable gardening group, including some professional landscapers, referred frequently to kaolin clay and Soil Solver in the most positive of terms.

I was too curious not to give it a go. I selected a bed that had fallen into disuse. This is one of those that I had emptied bag after bag of bentonite clay into over years, now back in its impoverished native state. It was entirely barren, even of weeds, having baked through Perth’s hottest summer on record. Here’s a pic.

I figured if Soil Solver could transform this parched write-off of a bed into a well-structured water-absorbent growing medium, then it had passed a pretty severe test.

Well, here’s that same bed a few days later after the Soil Solver treatment.

Where there was hopelessly deficient, water-repelling sand there is now loamy soil. It’s a pleasure to dig, holding together well on the shovel, a friable mix when turned. Water sinks straight into it. I NEVER got that result using bentonite clay.

I did a pH test on the treated bed and it was 7.5 – perfect for just about all vegetables.

What do the Plants Think?

This is the first harvest from a Chinese vege volunteer 3 weeks old. Quite simply, it was the best tasting Gai Lan we have grown in 20+ years of gardening. And within a fortnight, it was ready to harvest again!

This zucchini was planted into the Soil Solver-treated bed 5 weeks ago. What do you say but wow?

It’s early days, sure, but I am so impressed with Soil Solver that I felt I had to share my experience. Hence, this post.

How to Treat a Sandy Garden Bed with Soil Solver

There may be other ways of doing this, but I just did what it said on the tin – er, bag.

1. Spread the Soil Solver Clay Plus Minerals over the surface of the bed at a rate of 15kg per square metre along with an equal volume (volume, not weight) of Soil Solver Compost with Minerals. You could use a good quality DIY compost, but you’d be missing out on the additional minerals. And I figured I should follow the Soil Solver guidelines to give the products a proper trial.
2. Water and dig in.
3. Water again.
4. Repeat steps 1-3 as many times as necessary to fully integrate.
5. When fully integrated, cover generously with a good mulch. I used Dsatco lupin mulch. Protecting the soil with mulch is an important last step, allowing microbial activity to thrive beneath.

Note: Treating a neglected sandy bed like this with Soil Solver takes some elbow grease. I turned the soil and watered 3-4 times every morning for several days before I was satisfied the integration of clay, compost and sand was complete. This was during a heatwave; otherwise, I guess I could have done the job in a single session (or hired a rotary hoe). Alternatively, you could work in the clay and compost bit by bit over time, but I wanted to complete the treatment ASAP so I could immediately assess the result and plant into the bed.

The Financials

Soil Solver Clay Plus Minerals comes in 22.5kg bags, comprising pure premium WA kaolin clay, with minerals and silt. One bag treats 2.5 square metres. Retail cost varies – it pays to look around. The cheapest I have come across is $26.95 from www.lawndoctor.com.au.

That might seem relatively expensive, but bear in mind this is a one-off treatment. The combination of kaolin clay, minerals, silt and compost is all a bed of sand needs to be transformed into loamy vege-growing soil. Add Soil Solver Compost with Minerals from time to time, and top with mulch as required, and that’s it. Soil Solver products are mineral-based. No manure required! Factor this in, and over time a one-off Soil Solver Clay Plus Minerals treatment starts to look like a bargain!

Is Soil Solver Really a Permanent One-off Fix?

Dunno yet – so far so good! But even if a top-up is required from time to time, that’s OK with me. Beats digging in bags of manure and bentonite clay year after year and endlessly applying soil wetter.

Further, not using manure has advantages other than reducing expenditure and effort. According to the Soil Solver website, compost, manure and any vegetable-based material gradually turns soil hydrophobic. As an organic mineral-based product, Soil Solver works against soil hydrophobicity rather than contributing to it. Further, there are environmental benefits to dispensing with manure, which over time seeps into the water table and contributes to toxic algal bloom in lakes and rivers. Switching to mineral-based products like Soil Solver has a lot going for it.

I will report back from time to time on the progress of the treated bed (actually, beds – I am now intending to treat our other growing areas with Soil Solver). Whatever my findings, be assured I’ll be telling it straight. No gilding the lily here. That’s a promise.