Gardening wisdom passed through generations often carries more folklore than fact. Many well-intentioned practices, repeated year after year, lack scientific foundation and can actually harm plants rather than help them. Understanding which common beliefs are myths allows gardeners to make informed decisions, save time and resources, and ultimately cultivate healthier gardens. Here are five persistent gardening myths that experts urge you to reconsider.
Myth of gravel at the bottom of planters: useless ?
The drainage misconception
For decades, gardeners have placed a layer of gravel, stones or broken pottery at the bottom of containers, believing this improves drainage and prevents waterlogged soil. This practice seems logical: surely water will flow more freely through larger particles ? However, soil science reveals the opposite. Water does not move easily between materials of different particle sizes. Instead of draining away, water accumulates at the interface between soil and gravel, creating a perched water table that keeps roots sitting in saturated conditions.
The science behind proper drainage
Understanding how water moves through growing media explains why this myth persists yet fails in practice:
- Water clings to smaller soil particles through capillary action
- The transition zone between soil and gravel creates a barrier
- Roots remain in contact with excess moisture longer than intended
- The effective soil volume is reduced, limiting root growth
What actually works
Proper container drainage requires adequate drainage holes and quality potting mix formulated for containers. Choose compost that contains materials like perlite or vermiculite for aeration. If concerned about soil washing through large drainage holes, place a small piece of newspaper or coffee filter over the hole before adding compost. This allows water to pass whilst retaining soil.
Beyond container drainage, another myth concerns how we care for struggling plants.
The myth of fertilising diseased plants
Why feeding sick plants backfires
When plants show signs of distress, the instinct to provide extra nutrients seems compassionate. However, diseased or pest-infested plants rarely suffer from nutrient deficiency. Applying fertiliser to an already stressed plant forces it to produce new growth when it should be directing energy towards defence and recovery. This weakens the plant further and can exacerbate existing problems.
Identifying the real culprits
Before reaching for plant food, investigate the true cause of poor plant health:
- Inspect leaves and stems for pest infestations such as aphids or spider mites
- Check for fungal diseases indicated by spots, mildew or rot
- Assess watering practices, as both over and under-watering cause similar symptoms
- Consider environmental factors including light levels and temperature
- Examine soil conditions and root health
The correct approach to plant recovery
Once you have identified the actual problem, address it directly. Remove affected foliage, treat pest infestations with appropriate methods, adjust watering schedules, or relocate plants to more suitable positions. Only after resolving the underlying issue and observing recovery should you consider supplementary feeding to support renewed growth.
Just as plants need individualised care, trees also require assessment before applying traditional practices.
Should all newly planted trees be staked ?
The staking tradition questioned
Conventional wisdom suggests that every newly planted tree requires staking for support. However, research demonstrates that unnecessary staking can actually hinder healthy development. Trees naturally develop strength through movement, as wind causes stems to flex and stimulates the production of reaction wood. When overly supported, trees develop thinner trunks and weaker root systems, becoming dependent on artificial support.
When staking is appropriate
| Situation | Staking needed | Reason |
|---|---|---|
| Standard tree with heavy crown | Yes | Top-heavy structure risks toppling |
| Exposed, windy location | Yes | Excessive movement prevents root establishment |
| Loose or sandy soil | Yes | Roots cannot anchor effectively |
| Well-proportioned tree in sheltered spot | No | Natural movement strengthens trunk |
Proper staking technique
When staking proves necessary, use the lowest stake possible that prevents root rock. Position stakes outside the root ball, attach ties loosely to allow some movement, and remove supports after one growing season. Regular checks ensure ties do not constrict the expanding trunk.
Another tree care practice requiring scrutiny involves treating pruning wounds.
The myth of pruning paint for trees
The dangerous practice of sealing cuts
Applying wound sealants, pruning paint, or even household substances like nail varnish to pruning cuts seems protective. This myth suggests that covering wounds prevents disease entry and speeds healing. However, extensive research reveals that these products interfere with natural healing processes. Trees compartmentalise damage by creating chemical and physical barriers around wounds. Sealants trap moisture, encourage fungal growth, and prevent the formation of protective callus tissue.
How trees naturally heal
Understanding tree biology explains why interference proves counterproductive:
- Trees do not heal wounds like animal tissue; they isolate damage
- Compartmentalisation walls off affected areas from healthy tissue
- Callus tissue gradually covers exposed wood from the edges inward
- Chemical compounds within the tree resist pathogen invasion
Best practices for pruning
Support natural healing by making clean cuts with sharp, sterilised tools. Cut just outside the branch collar where natural protective compounds concentrate. Prune during appropriate seasons for each species, and avoid removing more than 25% of the canopy in a single year. Allow the tree to seal wounds naturally without interference.
Soil improvement techniques also require careful consideration to avoid counterproductive results.
Improving clay soil with sand: a bad idea
Why sand worsens clay problems
Heavy clay soil frustrates many gardeners with its poor drainage and difficult working properties. The temptation to add sand seems logical, yet this combination creates a concrete-like substance rather than improved growing medium. Clay particles are extremely fine, whilst sand particles are large. When mixed without sufficient organic matter, they pack together tightly, forming an impenetrable barrier worse than the original clay.
Effective clay soil amendments
Transform clay soil through organic matter incorporation rather than sand addition:
- Work in well-rotted compost or aged manure annually
- Add leaf mould to improve structure gradually
- Incorporate composted bark for long-term improvement
- Apply organic mulches that break down over time
- Avoid working clay when wet to prevent compaction
Long-term soil management
Improving clay requires patience and consistent organic matter addition. Microorganisms break down organic materials, creating humus that binds clay particles into larger aggregates. This process improves drainage, aeration and workability whilst maintaining nutrient-holding capacity. Expect noticeable improvement after two to three years of regular amendment.
Lawn care represents another area where traditional advice often misleads gardeners.
Myth of daily watering for a healthy lawn
The problems with frequent shallow watering
Many believe that daily watering keeps lawns lush and green. However, this practice encourages shallow root systems that make grass vulnerable to stress. When roots remain near the surface, lawns become dependent on constant moisture and struggle during dry periods. Frequent watering also promotes fungal diseases, encourages weed germination, and wastes significant water resources.
Optimal lawn watering strategy
| Frequency | Depth | Benefits |
|---|---|---|
| Once or twice weekly | 15-20cm deep | Encourages deep root growth |
| Infrequent but thorough | Soil moistened throughout root zone | Improves drought tolerance |
| Early morning application | Allows foliage to dry | Reduces disease risk |
Building resilient turf
Develop drought-resistant lawns through deep, infrequent watering that encourages roots to grow downward seeking moisture. Apply approximately 2.5cm of water per session, allowing soil to dry slightly between applications. During establishment, new lawns require more frequent watering, but gradually extend intervals as roots develop. Raise mowing height during dry periods to shade soil and reduce moisture loss.
Challenging these persistent gardening myths leads to healthier plants, more efficient resource use, and better understanding of how gardens truly function. Scientific research continues to refine best practices, demonstrating that traditional methods do not always serve plants well. By questioning inherited wisdom and seeking evidence-based approaches, gardeners can move beyond folklore towards practices that genuinely support thriving gardens. The key lies in understanding plant biology, observing results critically, and remaining open to changing methods when evidence suggests better alternatives exist.