Garden Myths That Keep Circulating — and the Facts Behind Them

This advice feels intuitive — water flows down, so a porous layer should help it escape. But soil science tells a different story. Water moves through a growing medium by capillary action and only drains past the soil-to-gravel boundary once the soil above is saturated. In practice, adding gravel shortens the column of soil water must travel through before hitting that boundary, which means the soil stays wetter longer, not drier. Roots in the saturated zone can rot. If drainage is a real concern, the solution is using a quality, well-structured potting mix and ensuring the pot has adequate drainage holes — not adding a gravel layer beneath the soil.

The slug claim rests on the idea that sharp shell edges deter soft-bodied pests. Controlled tests, however, have shown slugs crossing eggshell barriers without apparent difficulty. As for calcium: eggshells are mostly calcium carbonate, which is not water-soluble. They can take years to break down enough to release calcium into soil. If your soil genuinely lacks calcium, a soil test will confirm it and guide you toward an amendment that works on a gardening timeline. Composting eggshells is a fine way to keep them out of the landfill — just don't count on them to protect your hostas. Our home composting guide covers what scraps are worth adding to your pile.

The magnifying-glass theory is memorable, but peer-reviewed research — including a study published in New Phytologist — found that leaf surfaces scatter light rather than focus it in damaging ways under real-world conditions. That said, midday watering is still generally inefficient: water evaporates quickly in heat, meaning less reaches roots. Morning watering is recommended because foliage dries before nightfall, reducing fungal disease risk. So while the scorch story is a myth, the recommendation to water early is still sound — just for the right reasons. See our full watering timing guide for practical scheduling advice.

Fertilizer labels carry application rates for a reason. Nitrogen in excess produces lush, dark-green foliage but diverts the plant's energy away from flowering and fruiting. High salt concentrations from over-application draw moisture out of root cells — a process called osmotic stress — which presents as wilting or browning leaf tips that can look deceptively like underwatering. Before fertilizing, understand what your soil already provides. A basic soil test costs very little and removes the guesswork. When you do fertilize, follow label directions and factor in what your specific plants actually need at each growth stage.

"Plant it and forget it" is an appealing promise, but even well-adapted native species need regular watering during their first one to two growing seasons while root systems develop. Some natives spread by rhizomes or prolific self-seeding and require occasional editing to stay in bounds. The real advantages of natives are reduced need for irrigation once established, better resistance to regional pests and diseases, and genuine support for local pollinators and birds. Those benefits are worth pursuing — just with realistic expectations. Our article on why gardeners are embracing native plants goes deeper on what that maintenance reduction actually looks like.

Clay particles are extremely fine and pack tightly together. Adding a modest amount of coarse sand does not create the airy, well-drained soil most gardeners imagine — it can instead create a dense, hard-setting mixture, particularly if the sand is too fine. Soil scientists generally recommend improving clay soil by incorporating generous amounts of organic matter — compost, aged bark, or leaf mold — worked in over multiple seasons. Organic matter improves soil structure, promotes beneficial microbial activity, and gradually loosens compacted clay far more effectively than sand. If you're working with difficult native soil, a raised bed may be worth considering as an alternative.