10 Gardening Myths That Refuse to Die

From the well-intentioned advice of adding gravel to pots for better drainage to the romantic notion of planting by moonlight, these myths have taken root in gardening lore. 

Gardening myths are like weeds – they’re persistent, widespread, and can choke out good practices if left unchecked. 

Whether you’re a seasoned green thumb or just starting to dig into the world of plants, you’ve likely encountered some of these stubborn misconceptions.

From the well-intentioned advice of adding gravel to pots for better drainage to the romantic notion of planting by moonlight, these myths have taken root in gardening lore. 

In this article, we shed some light on ten of the most pervasive gardening myths that refuse to wilt away. 

So grab your favourite gardening gloves, and let’s dig into the truth behind these common misconceptions – your plants will thank you for it!

Myth #1: Adding Gravel to Pots Improves Drainage

You might have heard that adding gravel to the bottom of plant pots improves drainage, but this is a myth that can actually harm your plants. 

When you add a layer of gravel to the bottom of a pot, it creates a perched water table. This means water accumulates in the soil just above the gravel layer, creating a saturated zone which can lead to root rot.

By adding gravel, you reduce the amount of soil available for your plant’s roots, limiting their growth and the soil’s capacity to hold water and nutrients. Instead of improving drainage, gravel can block drainage holes, making the problem worse. 

For better drainage, use a well-draining potting mix with materials like perlite or vermiculite, choose appropriate containers, ensure proper drainage holes, and use the right watering techniques.


Myth #2: Watering Plants in Sunlight Burns Leaves

Garden Overwatering | Plant care

Another common myth is that watering plants in direct sunlight causes leaf burn. This is simply not true. The misconception likely arose from the idea that water droplets on leaves act like magnifying glasses, focusing sunlight and burning the leaves. 

However, scientific evidence shows that water droplets on leaves cannot concentrate sunlight enough to cause damage.

Leaf scorch is usually caused by environmental stressors like inadequate moisture, excess salt, wind stress, high temperatures, soil compaction, and inadequate potassium. While watering in full sun won’t burn leaves, it’s not ideal because of rapid evaporation. 

Morning watering is more efficient, allowing plants to absorb water before the heat of the day. But if your plants are stressed, it’s better to water them immediately, regardless of the time of day.


Myth #3: Coffee Grounds are Acidic and Good for All Plants

Many gardeners believe that coffee grounds are acidic and beneficial for all plants, but this is another myth.

 Used coffee grounds are not acidic. After brewing, their pH is close to neutral, typically between 6.5 and 6.8, so they won’t significantly lower soil pH or benefit acid-loving plants as commonly thought.

While coffee grounds contain some nutrients like nitrogen, potassium, phosphorus, and trace minerals, these are not readily available to plants and require decomposition by soil microorganisms. 

Coffee grounds can be beneficial as a soil amendment if used appropriately. They improve soil structure, drainage, and microbial activity, but should be used in moderation and preferably composted. Excessive amounts of coffee grounds directly in the soil can negatively impact plant growth.

The best way to use coffee grounds is by adding them to a compost pile. They contribute valuable organic matter and help maintain high temperatures in the compost. Additionally, a solution of brewed coffee can be an effective slug deterrent.


Myth #4: Pruning Paint Seals and Protects Cuts

pruning fruit tree wound paint | Plant care

Ever thought that pruning paint or sealers are essential after trimming trees? It’s a myth. Research has shown that these products can actually harm your trees. 

In the late 1970s, Dr. Alex Shigo, a renowned arborist, discovered that trees naturally seal off wounds. Pruning sealers can interfere with this process by damaging the cambium around the cut, trapping moisture, and promoting decay.

Modern arboriculture practices discourage the use of pruning sealers. Instead, focus on making clean cuts at the right time of year and avoiding damage to the branch collar. There are exceptions, like certain diseases in vineyards, but these are rare.


Myth #5: You Should Always Stake Newly Planted Trees

Think all newly planted trees need staking? Not always. Staking is only necessary in specific conditions like windy areas, slopes, sandy soil, or with bare root trees. 

Unnecessary staking can hinder tree development by reducing movement, decreasing trunk growth, and leading to smaller root systems. It can also cause rubbing injuries and make trees more likely to snap in high winds.

When staking is needed, do it right. Stake as low as possible, use flexible ties, and remove stakes after one growing season. Allowing trees to grow without stakes encourages stronger roots and better trunk growth.


Myth #6: Planting by Moon Phases Improves Growth

The idea that planting according to moon phases boosts plant growth is a popular myth. There’s no reliable scientific evidence supporting this. Studies have shown that the moon has little to no impact on plant physiology.

Despite this, lunar gardening has deep cultural roots. Ancient civilizations like the Egyptians and Chinese used lunar calendars in agriculture, which helps explain the myth’s persistence. Some gardeners may see better results because they’re more attentive to their plants, not necessarily because of the moon phases.

Proponents often cite the moon’s gravitational effects on tides, but this pull isn’t strong enough to affect soil moisture or plant water uptake. Claims about moonlight influencing growth are also unfounded, as moonlight is much weaker than sunlight.


Myth #7: Grass Clippings Cause Thatch

Ever been told that leaving grass clippings on your lawn will cause thatch buildup? This myth is misleading. 

Grass clippings decompose quickly because they’re mostly water, and they don’t contribute to thatch. Instead, they provide natural nutrients like potassium, nitrogen, and phosphorus as they break down.

Thatch buildup results from other factors like overwatering, over-fertilising, and certain grass types such as Bermuda and zoysia. To prevent thatch, focus on proper lawn care: regular mowing, aeration, and avoiding excessive nitrogen fertilisers are key.


Myth #8: Adding Sand Improves Clay Soil Drainage

clay soil 1 | Plant care

Adding sand to clay soil to improve drainage is a common misconception. This practice can create a dense, concrete-like substance. Effective soil texture change requires an impractical amount of sand—about 50% or more by volume.

A better solution is to add organic matter like compost, leaf litter, or well-aged manure. This approach enhances soil structure and drainage in both clay and sandy soils. Planting root-heavy cover crops and avoiding tilling can also help improve soil health over time.


Myth #9: Gardens Require Frequent Fertilisation

The idea that gardens need frequent fertilisation to thrive isn’t always accurate. Many plants do well without regular fertilisation if the soil is healthy. Over-fertilising can cause nutrient burn, excessive green growth, and environmental pollution.

Building healthy soil by adding organic matter and compost can minimise the need for fertilisers. Observe your plants’ specific needs to determine if and when fertilisation is necessary. Different plants have varying nutrient requirements, so adjust practices accordingly.


Myth #10: Adding Fertiliser to Planting Holes Helps Transplants

Think adding fertiliser directly to planting holes helps transplants? It can actually harm the plants. Fertiliser in the planting hole can curb root growth and potentially burn tender roots. Instead, amend the entire planting area with compost.

Focus on overall soil health and use proper planting techniques, like digging a hole twice as wide as the root ball but only as deep as the root system. Observing plant needs and using diluted organic fertilisers after planting, if necessary, promotes healthy growth.


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Linda Jones

Based in sunny Brisbane, Linda has a keen interest in ornamental plants. She firmly believes that gardens are as much about aesthetics as they are about functionality. Despite being a life-long gardener, she still enjoys learning about new plants and gardening techniques and sharing her discoveries with the Ultimate Backyard community. When she's not immersed in her garden, Linda loves reading and walking.


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