Is Molasses Good for the Garden?

Molasses in the soil? It’s not just a myth, it actually works.
But like most things in gardening, it’s all about balance.

Molasses is packed with natural sugars and trace minerals. When used properly, it feeds the beneficial microbes in your soil. These microbes help break down organic matter, unlock nutrients (especially potassium, calcium, and iron), improve soil structure and ultimately support stronger, healthier root systems

Think of it as a little energy drink for your soil, especially helpful after applying compost, worm castings, mulch, or during seasonal transitions.

Now healthy soil is great for everything but you’ll definitely notice a difference when you use it around native plants like grass trees and grevilleas (low nutrient lovers), veggies that thrive in biologically active soil, roses, citrus, perennials and lawns.

Like most things its not great if you overdo it. Too much leads to oxygen loss, mould, and nutrient tie-up. You also shouldn’t use if your soil is already heavy or waterlogged.

Always read the label.
Use plain molasses not sulphured molasses (the sulphur kills the very microbes you're trying to feed)

It is recommended that you
➤ Mix about 1 tablespoon of unsulphured molasses into a 9L watering can (that’s a 0.2–0.5% dilution)
➤ Pour around the base of your plants into the soil, not on the leaves
➤ Apply every 6 weeks if necessary

If you want to really boot your gardens, a follow up with seaweed tonic or worm juice to really get those microbes multiplying too.

Molasses when used wisely, can give your garden a biological edge, boosting resilience, root health, and overall soil vitality.

Just don’t treat it like maple syrup on pancakes and drown your plants.
A little sweet goes a long way

Myth Busting: The Vaseline Ant Trick

As with most garden myths, there’s a kernel of truth, so let’s pull it apart and deal with it properly.

The Truths:
Yes, ants farm aphids for their sweet honeydew. So in theory, if you control the ants, you reduce the aphid population. And yes, Vaseline has been used as a physical barrier to stop ants climbing.

The Reality:
Smearing Vaseline directly on your tree’s trunk, especially thin-barked trees like citrus or stone fruit, is a fast track to disaster. Petroleum jelly (Vaseline) suffocates the bark, traps moisture, and can cause ringbarking. With no application rate, no guidelines and just guesswork, that can kill your tree.

What should we do instead?

First, let’s talk about what’s really going on.
Excess ants usually (not always) point to hydrophobic soil. Soil that’s either not getting enough water or repelling it altogether. Ants love this. They build their nests in the dry root ball and actively repel water to keep their home dry. That means your plant stays dry too, stressed, weak, and vulnerable.

Then come the aphids, followed by scale and mites. Now the ants have a buffet and the whole thing snowballs.

Fix it this way instead:

• Drench the soil with a soil wetter, really soak it. This floods out the ants and starts restoring water flow.

• Follow up with a complete fertiliser like Organic Link to support recovery.

• Start a pest management routine: Spray fortnightly with something organic like neem or Eco-fend.

• Add a liquid feed (like Plant Care) every two weeks for a month to boost vitality and immunity.
  

It’s not instant but this approach is safer, more effective, and kinder to your trees in the long run.

Honey as an Alternative to Rooting Hormone

As with many horticultural myths, there is a kernel of truth...

While honey does not contain auxins (the plant hormones responsible for stimulating root development), it does offer properties that may support the rooting process under certain conditions.

• Honey exhibits well-documented antibacterial and antifungal properties, primarily due to its enzymatic production of hydrogen peroxide and high sugar concentration. When applied to cuttings, it may help reduce infection at the wound site, creating a cleaner environment for root initiation.

• Its viscous texture allows honey to seal the cut surface of a stem, limiting desiccation and offering some moisture retention. This can be helpful in environments with fluctuating temperatures or low humidity.

• Honey contains trace minerals, vitamins, and simple sugars, though in quantities too low to serve as significant nutritional supplements. Still, these components may support cell metabolism in early rooting stages.

Several studies have explored honey’s effectiveness as a rooting agent, with mixed outcomes:

• A study by the University of Hawai‘i, College of Tropical Agriculture, found that while honey demonstrated some ability to promote rooting, its effectiveness was limited and inconsistent compared to synthetic rooting compounds.

• A New Zealand nursery trial compared Manuka honey, multiflora honey, a commercial rooting compound, and a control group. Multiflora honey produced the best root development and the fewest failed cuttings—outperforming both the synthetic treatment and Manuka honey. This suggests that the type and processing of honey matter significantly.

If you are using this method, always use raw, unprocessed honey, as pasteurisation reduces both enzymatic and antimicrobial activity.

Seriously, though, no one should be buying honey from the supermarket anymore, anyway!

So, is the myth busted?

Not entirely. Honey may provide moderate rooting support, particularly for softwood or easy-to-root species, due to its antimicrobial qualities and wound-sealing ability.

However, it does not replicate the function of auxin-based rooting hormones (like IBA or NAA), which actively stimulate root initiation at the cellular level.

If you are in the mood for experimentation, certain types of honey can be useful when doing cuttings.

If you need results more than experiments, products like Rootex Cutting Powder or Gel should be used due to their consistency and proven performance.

Planting Myths: Digging Deeper into Compost and Root Health

A Garden Myth that I needed to  Dig a little Deeper on!

Recently, someone shared a quote from The Informed Gardener by Professor Linda Chalker-Scott, which argued that compost should be added only on top of the planting hole, not inside, and that planting holes should be as deep as the root ball but twice as wide.

I appreciate that this advice comes with good intentions, but as with most things in gardening, the truth is more nuanced.

Let’s break this down and explore what’s really going on below the surface.

How deep and wide should a planting hole be?

Linda Chalker-Scott recommends digging the hole only as deep as the root system and twice as wide.

This is generally good advice: planting too deep can cause settling and lead to burying the crown, which leads to rot. A wider hole encourages lateral root growth and helps roots establish in compacted or heavy soils.

When this works

In well-prepared soils or areas where compaction is minimal, this method encourages roots to spread into the native soil.

When this might fall short

In soils that are heavily compacted, hydrophobic, or of poor structure (like urban fill or degraded sites), simply making the hole wider without addressing the surrounding soil quality won’t necessarily help roots establish well.

Should you amend the planting hole at all?

The claim is that you should never amend the planting hole “in any way” and only backfill with native soil. The logic is to avoid creating a “pot effect” where roots stay in the nutrient-rich pocket and don’t venture into the surrounding soil.

There is truth here

If you fill the hole with soft, rich soil or lots of organic matter, especially in clay soils, roots can circle in the hole or fail to move into denser surrounding soils. Water can also perch at the boundary between two very different soil textures, leading to waterlogging at the root zone.

But context matters

In very poor soils, think subsoil, building rubble, or extremely sandy soils, some incorporation of well-aged compost or organic matter into the backfill can help create a healthier root zone. The key is blending the amendment with the native soil to avoid creating sharp boundaries.

Is compost in the planting hole always a bad idea?

The supporter’s comment suggested compost should only go on top as a mulch. While top-dressing with compost is great for feeding soil life and improving surface structure, a blanket ban on incorporating organic matter at planting doesn’t always hold up.

Top-dressing is fantastic

It feeds worms and microbes, protects soil from erosion, and slowly improves structure.

But moderate incorporation can be beneficial

Particularly in soils low in organic matter or with poor biological activity. It’s not about filling the hole with pure compost, but blending small amounts with native soil can jump-start root zone health.

Are we “spoiling” the plant with rich compost in the hole?

There’s a common belief that putting compost in the hole spoils the plant and encourages roots to stay put. But plants don’t get “lazy”, roots grow where water, air, and nutrients are available.

If surrounding soils are inhospitable, no amount of compost on top will change that. In these cases, improving the soil beyond the hole (via broad soil prep or blending amendments) is key.

Does this advice apply everywhere?

It’s important to note this recommendation came from Washington State, a climate with very different soils and conditions from, say, much of Australia. What works well in the Pacific Northwest may not directly translate to South East Queensland, where soils, rainfall, and temperatures differ.

The take-home message

There is no one-size-fits-all rule in gardening. The best planting method depends on your soil, plant type, and climate.

In the end, soil health and structure are what truly support thriving plants and that often means looking beyond the hole. 

I’d also add that the organic matter you’re adding has a shelf life. It breaks down within a relatively short period of time, so ultimately you’re giving your plant a good start but that’s all. Long-term soil health comes from ongoing care, not just what you put in the hole at planting.

So next time you hear a planting rule, take a moment to look at your own soil, your climate, and your garden’s needs. Gardening myths often have a seed of truth but real success comes from understanding the full story.

Gardening Myths: The Stories We Tell Ourselves

Planting myths often contain a seed of truth, but as any gardener knows, the real story is rarely so simple. In gardening, there’s rarely a one-size-fits-all rule. What works in one garden, climate, or soil type might be a disaster in another.

Let’s talk horticultural myths and gardening “truths” that aren’t quite right…

What have you believed or done in the garden that turned out to be misunderstood, outdated, or just plain wrong? Here are a few confessions to get us started:

Myth

Potting mix feeds your plants for 18 months

When potting mix says “feeds for 18 months,” that’s from the date of manufacture, not the day you open the bag. And no… they don’t put the date of manufacture anywhere on the packaging.

That’s why we always recommend feeding when planting, using something like Organic Link so you know exactly when the last feed happened. If in doubt, reapply every three months or with the turn of each season to keep nutrients consistent.

Myth

Full sun means all-day blazing sun

When a plant label says “full sun,” it simply means the plant needs at least 6 hours of direct sunlight per day. But not all sun is created equal.

Ipswich sun in December is a whole lot fiercer than Melbourne sun in December. So generally, if a plant tag says “full sun,” aim for sun-up to midday in hot climates — that’s a safe six hours for most plants.

And here’s the kicker: some plants can handle 12+ hours of blazing sunlight a day and thrive in it. Unfortunately, they’re labelled exactly the same as more delicate “morning sun only” plants. No wonder it gets confusing!

This is exactly why plant labels aren’t your only resource. Chatting to your local garden centre and their qualified horticulturists is the best way to get location-specific advice based on real experience.

Myth

Banana peels are a great potassium fertiliser

Banana peels just don’t have enough potassium in the peel to make much difference when used directly on your garden.

Let’s break it down: banana peels contain about 78mg of potassium per 100g, while a proper potassium fertiliser contains thousands of milligrams per application, plus it’s in a form that plants can actually absorb.

So while it sounds lovely to tuck a banana peel under a plant, you’re better off adding it to your compost where it can break down with other organic matter and contribute to long-term soil health.

If your plant needs potassium? Reach for a specific potassium-based fertiliser like Sulphate of Potash or Silica and Potash, especially during flowering and fruiting seasons.

The takeaway?

Read the label. Read your climate. And talk to someone who’s been there, killed that, and figured it out the hard way!

Have a gardening myth you’ve fallen for — or one you’re not sure about? Pop in and see us at Trevallan, or drop a comment below. We’d love to help you sort fact from fiction.

I’ve recently covered a few more myths you might like to explore

• Adding compost to your planting hole

• whether honey really works as a cutting compound

• the truth about molasses in the garden

• Ants and Vaseline

  Check them out and keep growing smarter!