Garden Myths That Are Surprisingly Widespread

This is one of the most persistent container gardening myths. The logic sounds reasonable: gravel is porous, so water should pass through it faster. In reality, water moving through soil doesn't simply drop into the gravel layer. Due to a phenomenon called a perched water table, water tends to accumulate just above the gravel until the upper soil is fully saturated. Only then does water cross into the coarser material below.

The result is that roots sit in overly wet soil for longer, increasing the risk of root rot — exactly what the gravel was meant to prevent. The actual solution is using a quality, well-structured potting mix and ensuring your pot has adequate drainage holes. See our container gardening guide for practical pot setup advice.

Coffee grounds have genuine value in compost, where they contribute nitrogen and help feed beneficial microbes. The problem arises when gardeners apply them directly and generously to garden beds or pots. Fresh grounds can mat together, forming a water-repellent crust on the soil surface. They also suppress certain soil organisms and, in large quantities, may inhibit the germination of some seeds.

Most garden plants prefer a neutral to mildly acidic soil pH. Acid-loving plants like blueberries or rhododendrons can benefit from occasional, small amounts of grounds worked lightly into the soil — but even then, testing your soil pH first is wise. A little, infrequently and mixed in well, is far safer than the heavy-handed applications often recommended online.

This belief has been repeated so often it feels like common sense. A study published in the journal New Phytologist examined the magnifying-glass hypothesis and found that while a theoretical effect exists under highly specific lab conditions, it doesn't translate meaningfully to real garden situations — most leaf surfaces are not smooth enough to focus light in a damaging way.

That said, there are still good reasons to water in the morning rather than midday. Morning watering reduces evaporation losses and gives foliage time to dry before nightfall, which lowers the risk of fungal disease. For a full breakdown of timing and technique, our watering guide covers what actually matters when and how you water.

The word "organic" describes where an ingredient comes from, not how selectively it acts. Pyrethrin, for example, is derived from chrysanthemum flowers and approved for organic growing — but it is highly toxic to bees and aquatic invertebrates. Copper-based fungicides, also organically certified, can accumulate in soil over time and inhibit beneficial microbial activity.

This doesn't mean avoiding all organic treatments, but it does mean reading labels carefully, applying at dusk when bees are less active, and exploring whether non-chemical methods are sufficient first. Managing pests without chemicals outlines practical first steps before reaching for any spray, organic or otherwise.

Plants have specific nutritional needs that vary by species, growth stage, and soil conditions. Applying excess fertiliser — especially synthetic formulations — can cause salt buildup in the soil that draws moisture away from roots, a process called fertiliser burn. Symptoms include brown leaf edges, wilting despite adequate water, and stunted fruiting in vegetables.

A soil test before adding any amendment is the most reliable starting point. It tells you what's actually deficient rather than guessing. For understanding how compost and fertiliser complement each other differently, our compost versus fertiliser guide explains what each does and when each is appropriate.