![\"Five](\"https:\/\/www.tomgrimshaw.com\/tomsblog\/wp-content\/uploads\/2026\/05\/Five_Garden_Myths.jpg\")
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Some garden advice gets repeated so often it stops being questioned. Five pieces that sound right \u2014 and aren’t .<\/p>\n
Gravel in the bottom of pots doesn’t improve drainage:
\n– A layer of gravel actually raises the wet zone into the root area instead of below it. A continuous column of potting mix with perlite mixed throughout drains better than a layered pot. Skip the gravel. Drill more holes.<\/p>\n
Watering in midday sun doesn’t burn leaves:
\n– Water droplets on smooth leaves don’t focus enough light to scorch tissue. This has been tested. There ARE good reasons to water in the morning \u2014 less water lost to evaporation, and foliage dries before evening when fungal infections are most likely. Water early for those reasons, not because of sunburn.<\/p>\n
Eggshells don’t add calcium quickly:
\n– Eggshells are one of the slowest-decomposing organic materials in soil. Crushed by hand and tossed in the garden, they take years to release anything a plant can use. If you want them to break down in one season, grind them to a fine powder first. Coarse pieces are still sitting in the soil when the next season starts.<\/p>\n
Used coffee grounds don’t acidify soil:
\n– Brewing extracts most of the acid. Used grounds test nearly neutral. They’re a fine addition to compost as a nitrogen source, but they won’t lower pH for blueberries or azaleas the way most people assume. And don’t spread them thick as a surface mulch \u2014 they form a water-repellent crust. Mix them into compost instead.<\/p>\n
Marigolds don’t repel most pests:
\n– French marigold roots release a compound that suppresses a specific type of soil-dwelling nematode. That’s real, but it’s underground and it’s specific. Marigolds planted among tomatoes don’t repel aphids, beetles, caterpillars, or anything above ground. The strongest effect comes from growing marigolds as a cover crop and turning them into the soil at the end of the season \u2014 not from tucking a few plants between your vegetables.<\/p>\n
Five corrections. Same garden. Better decisions.<\/p>\n","protected":false},"excerpt":{"rendered":"
Some garden advice gets repeated so often it stops being questioned. Five pieces that sound right \u2014 and aren’t . Gravel in the bottom of pots doesn’t improve drainage: – A layer of gravel actually raises the wet zone into the root area instead of below it. A continuous column of potting mix with perlite … <\/p>\n