How Rockdust Works to Improve Soil Health
Rockdust sounds like one of those gardening products that could either be a quiet achiever… or complete woo. In a recent masterclass series, the topic came up more than once—and for good reason. This finely ground rock has gardeners talking, thanks to its slow-but-steady way of boosting soil health and supporting more resilient, productive plants. Think of it as the unsung hero of the garden, quietly working behind the scenes while you get on with planting, watering and wondering why your veggies are suddenly looking so smug.
Rockdust is exactly what it says on the bag: finely ground rock, usually basalt or granite. In nature, rock weathers down over years (or centuries, if you’re being really patient). rinding rock into dust speeds this up by increasing the surface area, giving soil moisture, plant roots and soil microbes more chance to get to work.
The result is a slow, steady release of secondary nutrients and trace elements such as calcium, magnesium, iron and manganese.
It’s not a fertiliser, so don’t expect an instant green-up, but it quietly supports long-term soil health. By slowly topping up minerals that garden soils can lose over time, it helps keep your soil—and your plants—happy.
When added to soil, rockdust can help remineralise the soil, support better structure, improve moisture retention, and even enhance drainage. The payoff? Healthier, more resilient plants with robust roots and a quiet confidence that comes from being well-fed at the mineral level.
Think of rockdust less like a quick coffee for your plants, and more like a slow, nourishing stew for your soil. It works best in biologically active soils, where microbes and fungi can help unlock those minerals. On its own, it won’t perform miracles. Paired with compost, mulch and good soil care, it can quietly support healthier soil structure and more resilient plants over time.
When to Use Rockdust for Soil Health
Rockdust can be particularly useful in sandy or well-worn garden beds, where minerals have had a habit of washing through or being used up by repeated cropping. If your soil has been working hard for you (and hasn’t had much mineral love in return), rockdust can help broaden its mineral pantry.
For most home gardens, around 100 grams per square meter is plenty. It can be sprinkled over the soil and watered in, or mixed through compost so it’s easier to spread evenly.
Autumn and spring are ideal times to apply rockdust, when moisture and soil life are more active and better able to get to work on those mineral particles. It’s also a good addition when setting up new garden beds, so the soil starts life with a broader mineral base.
Rockdust can be used across vegetables, ornamentals, lawns, fruit trees and native plantings. This is one of those quiet, sensible inputs that supports long-term soil health — not a flashy fix, but a solid background player that earns its keep over time.
Rockdust Staying Power
Adds essential minerals to soil
90%
Instant results
20%
Effectiveness on its own
40%
Soil Structure Improvement
60%
Support for Plant Health
70%
Cost-Effectiveness
85%
Where to Find Rockdust
Rock dust products are available through garden centres and hardware stores in bagged form. For larger volumes, materials sold as basalt fines, crusher dust or bluestone fines are commonly used. These are by-products of quarrying and are widely available from landscape suppliers, making them a relatively cost-effective option. When sourcing in bulk, it’s important to confirm the material is untreated and free from contaminants, as some crusher dusts are blended or stabilised for construction use.
Top Tip: If you are a Friend of SGA, check out Backyard Botanist for a 10% discount on their Rockdust Mineral Soil Food product. Login to your FOSGA account for discount partner details.
Want to Learn More? Join Our Masterlass on Jan 29!
Curious to see rock dust and other amendments in action? Our Soil, Compost, Potting Mix and Natural Amendments 101 Masterclass is the perfect place to get hands-on advice and practical know-how.
In this one-hour online session, you’ll learn:
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The differences between garden soil, compost, and potting mix — and when to use each
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How to feed your soil for healthier, more productive plants
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Practical tips for applying natural amendments like rock dust, compost, and more
Whether you’re a newbie or just need a refresher, this Master Class will give you the confidence to make science-backed choices that truly support your garden.
Secure your spot and give your soil the boost it deserves!
Borage (Starflower): A Refreshing Herb with Hidden Depths
Borage (Borago officinalis), often called starflower, is a large annual herb reaching up to a metre in height. Its large, prickly, hairy leaves (which can cause a rash) and delicate small purple star-shaped flowers bloom from spring to autumn—an irresistible draw for bees and pollinators. Simple to grow and self-seeding, borage thrives in full sun, with moisture in summer, and isn’t picky about soil. Planting in small clusters helps the plants support each other.
Borage flowers typically open pink before maturing to a vivid blue—a clever natural strategy to draw in bees. Since true blue is a rare colour in most gardens, these blossoms stand out beautifully and act as magnets for beneficial pollinators, making borage a wonderful way to add both colour and life to your garden.
The edible flowers have a crisp cucumber flavour and are perfect as garnishes in salads, sandwiches, or mashed into cream cheese. They’re even delightful in ice blocks, cocktails (often used instead of mint), or floating atop drinks. Leaves can add a fresh twist to sauces or puréed soups. A word of caution: borage shouldn’t be consumed in large doses or during pregnancy.
Borage seed oil is prized for its metabolism-regulating and hormone-balancing properties—particularly helpful for PMS or menopause symptoms. Plus, it’s the richest known natural source an omega-6 fatty acid linked to anti-inflammatory benefits.
What you may not appreciate about Borage is that it is a dynamic accumulator. It draws up potassium and other nutrients from the soil. So, when chopped and used as mulch or added to compost, it can really enrich garden soil for other plants.
With its stunning blooms, culinary versatility, medicinal promise, and garden-enhancing traits, borage is a real star in a sustainable garden.
Locking in Problems - The Hidden Costs of Landscape Glue
When you go shopping for products that might help with problems you have in your garden, you might spot landscape glue. It is right next to the pesticides and herbicides — a pretty good clue they’re not exactly friends of a sustainable garden. Products like landscape glue, pebble glue, gravel binder, decorative stone adhesive, and resin binder (often sold under various “lock” brand names) promise a perfectly neat, no-fuss look. They’re sprayed over pebbles, gravel, or mulch to hold everything in place, preventing movement from wind or rain. But that tidy finish comes with hidden costs for you, your garden’s and the wider environment’s health.
What is in landscape glue?
The vast majority of these products have one of two active ingredients in them that create a semi-permanent bond between the material it is applied to. These products are either water-based polyurethane or acrylic polymers. They may also have other additives like filling agents, plasticizers, or solvents. When applied, the liquid makes the material shiny, clear and static. The claims that these products are low maintenance are based around their reducing weeds, keeping stones or mulch in place, and creating a neat appearance.
Healthy Concerns
Landscape glue poses significant health and environmental concerns that are often downplayed by marketing claims. According to the Safety Data Sheet, the product is highly hazardous to humans during application, with risks to the skin, eyes, and respiratory system if proper protective equipment is not used. Beyond the effects on human health, it is also toxic to aquatic organisms, raising serious questions about its impact if residues wash into waterways. Despite this, some manufacturers boldly claim on bottle labels that the product is “safe for plants, animals and humans”— a statement that appears misleading and contradictory to the detailed warnings provided in their own documentation. This discrepancy highlights the importance of reading Safety Data Sheets carefully rather than relying on marketing slogans that can obscure real risks.
Environmental and Sustainability Concerns
The environmental impacts of landscape glues are well-known, but people don’t usually link them to this product -
Microplastic Pollution
Polyurethane and acrylic polymers are plastics — even if water-based, they don’t biodegrade in any meaningful timeframe. Over time, weathering and UV light cause the bonded surface to break into microplastics. These particles infiltrate soil ecosystems and can leach into stormwater, eventually reaching waterways. Microplastics can be ingested by soil organisms, insects and aquatic life, disrupting feeding and reproduction and have recently been linked to many human health issues, such as cancer.
Soil Life Disruption
Many of these products claim to allow water and air through, but in reality, the hardened bonded layer restricts the natural exchange of air, moisture and organic matter between the surface and the soil. This effectively suffocates beneficial microbes, fungi and invertebrates — all crucial players in the nutrient cycling that keeps soil and plants healthy. Worms and burrowing insects can’t move freely beneath a glued surface and the resulting drop in biodiversity leaves the soil less able to withstand drought, pests and disease. Some might argue that such locked surfaces are no different from a non-permeable path like concrete, but the key difference is that resin-based glues gradually break down, releasing plastics and additives into the environment.
Chemical Leaching
These products contain plasticizers, fillers and solvents that can leach into soil, particularly as the product weathers. These additives may include phthalates, formaldehyde-releasing agents and heavy-metal catalysts. Runoff can carry these into drains and waterways where they affect aquatic organisms.
Heat Island & Water Stress
The sealing process often darkens the pebble surface which then increases the amount of heat it absorbs and radiates. This is certainly a lot more than vegetated areas. Such heating stresses nearby plants and can raise garden the temperature of microclimates making them less hospitable for sensitive species.
Misleading Claims
Landscape glues are marketed as “Water-based”, but this only refers to the carrier before curing — the final product is still plastic. These products are often advertised as “low VOC” or “non-toxic” during application, which hides the problem of long-term environmental persistence. Weed seeds still blow in and grow between glued stones — but are harder to remove. It reminds me of artificial grass and how that is advertised as an easy, low maintenance option to reduce weed growth when, in fact, it isn’t.
End-of-Life Waste
Once pebbles are glued together with landscape adhesive, they become a single block of stone and plastic. Some makers claim the glue eventually breaks down, but what about the stones where it doesn’t or those left with glue residue and the impacts of breakdown products? Because the adhesive is so hard to remove the stones can’t be reused or recycled like loose gravel. Taking glued layers apart usually means using heavy tools or harsh chemicals – a task which is messy and difficult. In most cases, the whole surface ends up in landfill. The real issue isn’t the stone—it’s the plastic glue which breaks down extremely slowly and can remain in the environment for decades or even centuries.
Sustainable Alternatives
Most of you will appreciate the negative impact of these landscape glues, but as a gardener you are an influencer, so talking to other gardeners and friends about it is really important. And talking about alternatives to using pebbles with glues is a part of that:
- Loose Pebbles with Weed-Suppressing Groundcovers - Use plants like creeping thyme, dichondra, or native low-growers.
- Organic Mulches - Wood chips, bark, straw feed soil as they break down.
- Permeable Hardscaping - Unbonded gravel, pavers with wide joints, permeable concrete.
Gardens work best when they’re alive and changing, not fixed in place. Healthy gardens let rain soak into the ground, give soil creatures air and food and adapt naturally with the seasons. Such adaptation keeps the soil rich, supports plants and wildlife and makes the garden stronger over time. Using landscape glue does the opposite—it seals the surface, blocks water and air from reaching the soil and stops natural cycles from happening. Instead of helping the garden thrive, glued surfaces create a hard, lifeless layer that gets in the way of ecological gardening.
In the end, pebble glue might make a garden look neat for a while, but it comes at a cost to you, your garden and the wider environment. Not only does a glued surface stop soil from breathing and slows other natural systems, but it also stops you having flexibility to tinker and to move and change things in your garden. The easiest and quickest way to make your organic garden look neater is to have messy ecosystems in orderly frames (Nassauer 1995). Use natural materials for paths and to edge your garden beds so that you are working with nature. Such materials will support soil, plants and wildlife and allow resources to be recycled or returned to the earth.
Shade Gardening
Following the recent announcement from the Bureau of Meteorology predicting a hot and windy summer for 2025, it’s evident that we are already feeling the effects of climate change. With increasingly frequent extreme temperatures and unpredictable weather, our summer shading strategies can no longer consist of draping sheets over plants during the occasional hot days. We’ve moved beyond that. We need removable shade structures that can remain in place for days while still allowing the plants to thrive underneath.
Watering alone is not enough
As a fan of wicking beds, I’ve learned that even with plenty of water, intense sunlight can still harm your crops. We can’t rely solely on watering to combat extreme heat. While it may see counterintuitive—since summer vegetables thrive in sunlight—creating shade in vegetable gardens is becoming increasingly essential. Shade not only protects crops from harsh sunlight and sunburn but also conserves soil moisture and reduces heat stress, leading to healthier plants and improved yields. Even for sun-loving crops like tomatoes and cucumbers.
Cool it!
Recently, I participated in a community workshop at the Farnham Street Community Garden in Flemington as part of their 'Cool It' Project. Focusing on climate resilience, the workshop explored transforming vulnerable spaces into thriving gardens, with both natural and manmade shading approaches.
Food forests for shade
Food forests offer a natural way to enhance your garden's resilience against extreme heat. Consider the refreshing coolness to be found in a wooded area on a hot day—this is the same concept behind a food forest, where dense layers of foliage provide mutual protection. However, not everyone can establish a food forest; some prefer to use distinct garden beds for growing their food.
Framing options for shade
Many off-the-shelf wicking beds offer exclusion netting frame options, which can be adapted with shade netting. But if you’ve built DIY wicking or raised beds, these may not be suitable. At the Cool It session, I 
learned that effective solutions can often be found in hard rubbish, reusing materials and taking it a sustainability step further. Clothes airers and PVC piping can be upcycled to create all manner of solutions. These lightweight yet sturdy materials can protect specific plants or areas in your garden beds. Alternatively, you can use simple "build-a-frame" kits with metal brackets and garden stakes to cover entire beds. Net securing methods can vary based on your resources and preferences; stainless steel clasps work well, but skilled sewers can attach Velcro straps or go for the fitted net approach relatively easily.
Don't forget about pollination
When designing your shade, keep in mind that most summer vegetables depend on pollination for fruit development, and nets can hinder this process. It’s important to design your temporary structure with flexibility in mind, keeping it small enough so you can remove it entirely for periods of time or at least have the ability to roll up one side of a larger netting installation. This will give pollinators access to the flowers when it’s cooler. You also need to be able to harvest your vegetables easily. Many summer fruiting vegetables rely on regular picking to keep them producing.
I can't wait to hear how the ‘Cool It’ project progresses as it tests out different styles of netting and shapes and strategies this summer. The project has been grant funded by Moonee Valley City Council, to explore garden resilience techniques. We'll be sure to share their findings.
Three Main Benefits of Shading Your Vegetable Garden
Temperature Regulation: Shade lowers soil and air temperatures, reducing heat stress on plants.- Moisture Retention: By filtering sunlight, shade decreases evaporation, helping maintain soil moisture crucial for healthy root systems.
- Extended Growing Season: Shaded areas can create microclimates that allow crops to thrive longer.
Using a shade cloth is an effective option to build resilience to food growing in the summer months, but there are some other alternatives which are a little simpler and less committed than a full-on food forest -
- Companion Planting: Taller plants, like sunflowers, can naturally shade shorter vegetables, maximizing space. Easy to create than a full scale food forest
- Trellises and Arbors: These structures provide shade for climbing plants while sheltering others beneath or behind.
- Utilizing Existing Structures: Position your food garden near trees or fences to take advantage of natural shade.
As climate conditions are set to evolve, incorporating shade into vegetable gardens is becoming increasingly important to improve our gardens resilience and the production of food. The strategies above benefit both you and your garden, and when adopted by the community, they contribute to sustainable food systems in an unpredictable climate.
Garden Journaling - Slow down to tune in.
As we move through the year and our gardens evolve, there's something magical about documenting the journey. Garden journaling is an art that enables us to cultivate memories as we cultivate plants. It provides an opportunity to savour the beauty of our outdoor space, connect with it, and understand it. There's nothing more mesmerising than watching a bee meticulously clean pollen from its body and delicately store it in its legs.
Connection - Writing a journal makes you slow down and connect. In the hustle and bustle of everyday life, our gardens provide a refuge, a tranquil space where we can reconnect with nature. A garden journal becomes a bridge between the gardener and the garden, offering a canvas to capture the vibrant colours, fragrances, and the symphony of sounds that define each day in the garden. Journals help you appreciate and be inspired by your garden.
Chart Growth - Imagine flipping through the pages of your journal and witnessing the miraculous journey of a tiny seed transforming into a flourishing plant or an abundant crop. Garden journaling allows us to record the growth and development of our plants, serving as a valuable resource for future seasons. It becomes a personalised almanac, offering insights into the timing of blooms, pruning schedules, and the successes (or challenges) of different varieties. This is becoming increasingly more important as our climate changes and moves away from the historical and well documented patterns in many of our much loved resources.
Solace - Gardening is therapeutic, and so is the act of documenting it. Journalling provides an avenue for self-reflection, allowing gardeners to express their ideas, thoughts, feelings, and observations. Whether it's the satisfaction of a successful harvest of the biggest pumpkin, or the resilience of a plant overcoming a heat event, a garden journal becomes a place to celebrate triumphs and learn from the setbacks, which gardens are full of.
Designing Dreams - For those that have big dreams and a flair for design, a garden journal can be a creative outlet. Use it to sketch out new layouts, experiment with color combinations, and plan for future additions. Your journal can evolve into a personalised gardening blueprint, helping you bring your dream garden to life. And to keep you on track when you see a plant sale at the nursery!
Digital Diarising - In the digital age, sharing our gardening experiences has never been easier. Consider starting a garden journalling community, either online or within your neighbourhood. Exchange tips, share photos, and inspire one another to create a network of green enthusiasts dedicated to nurturing their outdoor spaces. 
Tips for Starting Your Garden Journal:
- Choose the Right Journal: Opt for a journal with sturdy, weather-resistant pages that can withstand the elements, but nothing so pretty you’re going to be too scared to start to use it!! Having good quality paper will make a difference if you're going to stick items into it.
- Include Details: Note the date, weather conditions, and any noteworthy observations each time you make an entry. And incorporate sketches, photographs, or even pressed leaves or flowers to add a visual dimension to your journal.
- Make It Personal: Your garden journal is a reflection of your unique gardening journey. Feel free to infuse it with your personality, anecdotes, and even a bit of humour.
- Stay Consistent: Make it a habit to journal regularly, even if it's just a quick update. Consistency will help you track patterns and changes over time. If it becomes a chore, then stop journalling. Wait to be inspired to write again.
Garden journaling is a delightful practice that adds real depth and meaning to our gardening experiences. So, grab your favourite journal, head to the garden, and let the pages of your botanical adventure unfold.