Question 1

A layer of gravel or pot shards at the bottom of a container improves drainage.

Accepted Answer

The old "never put gravel in the bottom of a pot" rule turns out to be overstated — a recent controlled test found a coarse bottom layer usually helps drainage a little or does nothing, not that it hurts. It's also no cure: a good potting mix and a real drainage hole matter far more. Layer or don't; just don't count on it to fix a soggy mix.

Question 2

Adding sugar or molasses to the soil makes tomatoes and other fruit sweeter.

Accepted Answer

Sugar in the soil won't sweeten your tomatoes — roots can't take up sucrose, and fruit sugar is made in the leaves by sunlight. For sweeter fruit: full sun, healthy foliage, a sweet cultivar, and letting it ripen on the plant (a little less water late in the season helps concentrate it).

Question 3

Basil improves the flavour of adjacent tomatoes.

Accepted Answer

There's no evidence for this and no mechanism anyone has proposed. Plant basil next to tomatoes anyway — you'll want them at the same time in the kitchen.

Question 4

Bone meal helps transplants and bulbs put down roots.

Accepted Answer

Bone meal isn't a rooting tonic. It's phosphorus, and unless a soil test shows your soil is short of it, adding more won't grow better roots — phosphorus hardly moves in soil and stays locked up in neutral or alkaline ground anyway. Plant at the right depth, water evenly, and soil-test before adding phosphorus; too much can even set back the fungi that help roots.

Question 5

Burying banana peels feeds plants potassium (roses in particular).

Accepted Answer

Banana peels do hold some potassium, but a buried fresh peel releases next to nothing until it rots — months away — and can draw pests in the meantime. Compost them instead; if a plant needs potassium, a soil test tells you, and a balanced amendment delivers it now.

Question 6

Burying rusty nails adds iron that greens up plants and turns hydrangeas blue.

Accepted Answer

Rusty nails won't green up your plants or turn hydrangeas blue. Yellow leaves usually mean iron is locked up by high pH, not missing — and a nail's iron isn't available anyway; hydrangea blue is an aluminium-and-pH effect, nothing to do with iron. Soil-test first, then lower pH (elemental sulfur) or use a chelated-iron feed for yellowing, and acidify the soil to blue a hydrangea.

Question 7

Chives or garlic planted under a fruit tree prevent apple scab.

Accepted Answer

There's no evidence that chives or garlic under an apple tree prevent scab, and no mechanism for it - scab lives in last year's fallen leaves and infects in wet spring weather. Choose a scab-resistant variety, rake up and bin the dropped leaves, and you've done the things that actually work.

Question 8

Cinnamon or chamomile tea prevents damping-off in seedlings.

Accepted Answer

Cinnamon and chamomile tea are popular anti-damping-off remedies because cinnamon is antifungal in a lab dish - but there's no good evidence either one saves a seed tray. What prevents damping-off is the setup, not a topping: fresh sterile mix, clean pots with drainage, warmth and airflow, and going easy on the water.

Question 9

Coffee grounds acidify soil.

Accepted Answer

Used coffee grounds are close to pH-neutral — brewing washes the acid out — so they won't durably acidify your soil or make it blueberry-friendly. Compost them or use a thin mulch for the organic matter; to lower pH, use elemental sulfur guided by a soil test.

Question 10

Coffee grounds scattered around plants repel slugs, snails, and other pests.

Accepted Answer

Coffee grounds don't reliably repel slugs or other pests — the idea comes from caffeine being toxic to slugs in the lab, but used grounds carry far too little to work as a barrier, and trials don't back it. Use beer traps, night hand-picking, or iron-phosphate bait for slugs; compost the grounds or spread a thin mulch for the organic matter.

Question 11

Companion planting charts encode real relationships.

Accepted Answer

Most companion planting advice you'll find online is folklore. Here's what we can actually defend, and why.

Question 12

Compost tea (or manure tea) greatly boosts growth and suppresses plant disease.

Accepted Answer

Compost tea is a weak liquid feed at best — no better than using the compost itself, which also improves the soil the tea can't. The "cures disease" claims don't hold up in trials, and a badly brewed or manure-based tea can grow harmful bacteria you don't want on food crops. Put your compost on the beds; skip the tea as a disease cure.

Question 13

Crushed eggshells deter slugs.

Accepted Answer

Eggshells don't reliably deter slugs — they cross far sharper surfaces on their mucus layer, and the "barrier" weathers away fast. Use beer traps, night hand-picking, or iron-phosphate bait; put the shells in the compost for the calcium.

Question 14

Crushed eggshells in the planting hole prevent blossom end rot.

Accepted Answer

Eggshells in the planting hole won't stop blossom end rot. BER is a calcium-transport problem caused by uneven watering, not a soil-calcium shortage — and eggshell calcium takes seasons to break down, so it isn't available this year regardless. Water evenly, mulch to steady the moisture, and soil-test before adding anything.

Question 15

Dish soap makes a safe, effective homemade insecticide, the same as insecticidal soap.

Accepted Answer

Dish soap isn't the same as insecticidal soap — detergents strip the leaf's protective wax and can burn foliage, so the "safe homemade spray" idea backfires. It does kill some soft-bodied pests, but if you want a soap spray, use a real insecticidal soap made not to harm the plant.

Question 16

Epsom salts prevent blossom end rot.

Accepted Answer

Epsom salts won't stop blossom end rot. BER is a calcium-transport problem caused by uneven watering, not a magnesium shortage — and added magnesium competes with calcium uptake. Water evenly, mulch to buffer soil moisture, and soil-test before adding anything.

Question 17

Fresh manure is a safe, ready-to-use fertiliser you can spread straight onto the garden.

Accepted Answer

Fresh manure isn't a ready-to-use fertiliser. It burns plants with ammonia and salts, and raw manure can carry harmful bacteria like E. coli and Salmonella — a real food-safety risk on vegetables. Compost or age it first, or keep raw manure well clear of the harvest (guidance sets months between spreading and picking). Well-rotted manure or finished compost is the safe version.

Question 18

Household vinegar is an effective weed killer.

Accepted Answer

Vinegar only burns the tops of small, young weeds — it doesn't reach the roots, so established and perennial weeds grow right back, and it kills whatever it touches, including your crops. The stronger "horticultural" vinegar is caustic, not gentle. Use it for seedlings in pavement cracks, not as a lawn-and-bed weed killer.

Question 19

If you buy good compost or bagged soil, your native ground underneath doesn't matter.

Accepted Answer

Buying good soil doesn't let you ignore the ground underneath. A thin layer over compacted native soil perches water at the boundary, and roots reach the native soil within a season anyway. Improve your own soil with organic matter over time; if drainage is truly bad, go with a tall raised bed or containers rather than a shallow cap of bagged mix.

Question 20

Marigolds repel most garden pests and protect the whole garden.

Accepted Answer

Marigolds don't repel pests in general. Their one real effect is narrow: a dense planting of the right Tagetes, grown before a crop, suppresses root-knot nematodes in the soil (not a scent that wards off flying insects). Enjoy them for colour and pollinators; use the nematode trick on purpose if you need it.

Question 21

Mixing sand into clay soil improves its drainage.

Accepted Answer

Don't add sand to clay to "loosen" it — in the amounts anyone actually adds, the clay fills the gaps and you get a denser, worse-draining mix. Work in compost and mulch instead; organic matter is what builds the structure that drains.

Question 22

More fertiliser means bigger, healthier plants.

Accepted Answer

More fertiliser doesn't mean bigger, healthier plants. Past what a plant actually needs, the extra burns roots, pushes weak leafy growth over fruit, and runs off into waterways. Feed what the soil is short of, not more — and a soil test is what tells you the amount. When in doubt, less.

Question 23

Planting by lunar phase improves germination and yield.

Accepted Answer

No mechanism, no trials. Plant when the soil is warm and the frost risk has passed.

Question 24

Radishes deter flea beetles.

Accepted Answer

Radishes don't repel flea beetles - flea beetles like radish, which is why some gardeners use it as a trap crop and sacrifice it. If your radish leaves are riddled with tiny holes, that's flea beetles doing exactly what they do; it isn't protecting your other brassicas by scent.

Question 25

Seeds saved from hybrid vegetables grow true to the parent plant.

Accepted Answer

Seeds from a hybrid won't grow true to the parent. An F1 hybrid's seed scatters the traits — you get a mixed, often weaker crop, not a copy. If you want to save seed that comes true, grow open-pollinated or heirloom varieties; saving hybrid seed is a fun experiment, not a way to keep a variety.

Question 26

Spraying diluted milk on the leaves prevents or cures powdery mildew.

Accepted Answer

Milk spray for powdery mildew is the rare home remedy with real trials behind it — diluted milk cut mildew on squash and cucumbers in field studies, sometimes as well as a fungicide. But it isn't a guaranteed cure: results swing with crop and weather, and it's a preventive, not a rescue. Use it if you like, but lean first on resistant varieties, good spacing and airflow, and pulling infected leaves.

Question 27

Spraying plants with dissolved aspirin boosts their immune system and health.

Accepted Answer

Aspirin spray isn't a proven plant tonic. There's a real kernel — salicylic acid does trigger a plant defence response in the lab — but home dosing is guesswork, results in the garden are inconsistent, and too strong a mix burns leaves. Lean on resistant varieties, airflow, clean tools, and pulling infected leaves; treat aspirin as a curiosity, not a routine.

Question 28

Spreading cornmeal on soil or lawns cures fungal disease.

Accepted Answer

Cornmeal isn't a reliable fungicide. The idea comes from a real finding that it can feed a beneficial soil fungus, but that hasn't panned out as a lawn or garden disease cure in trials. Manage fungal problems with drainage, airflow, resistant varieties, and clearing infected debris — and don't confuse it with corn gluten meal, a separate weed product.

Question 29

Sprinkling baking soda around tomato plants makes the fruit sweeter.

Accepted Answer

Baking soda won't sweeten your tomatoes. Sweetness is sugar the plant makes in its leaves from sunlight, not something soil pH controls — and baking soda's sodium actually harms soil and roots. For sweeter fruit: a sweet cultivar, full sun, healthy leaves, and letting it ripen on the plant.

Question 30

Sprinkling human hair, soap shavings, or urine around the garden reliably keeps deer and rabbits out.

Accepted Answer

Hair, soap, and urine "deterrents" fade fast and animals get used to them — they're not a reliable defence. If deer or rabbits are a real problem, a fence of the right height is the only dependable fix; rotate a commercial repellent and choose resistant plants to help.

Question 31

Talking to your plants, or playing them music, makes them grow better.

Accepted Answer

Talking to or playing music for your plants won't grow them faster on its own — but the attention that comes with it will, because you'll spot thirst, pests, and shade sooner. Do it if you enjoy it; then act on what you notice.

Question 32

Watering a little every day is the best way to water a garden.

Accepted Answer

Watering a little every day usually isn't best — it keeps roots shallow and thirsty, so plants cope worse when it's hot. For established plants, water deeply and less often, and let the top of the soil dry between soakings. The exceptions are real: seedlings, new transplants, and containers dry out fast and may genuinely need water daily.

Question 33

Watering plants in the midday sun scorches the leaves (water droplets focus sunlight like lenses).

Accepted Answer

Watering in the midday sun won't scorch your leaves — droplets don't focus light onto the leaf, and they evaporate before they could. Water whenever the plant needs it — but aim at the soil rather than the leaves, because wet foliage invites fungal disease. Morning or evening just wastes less to evaporation.

Question 34

Watering with hydrogen peroxide oxygenates the roots and cures root rot.

Accepted Answer

Hydrogen peroxide won't oxygenate your roots or cure root rot. It does give off oxygen, but in soil it fizzes away in seconds, and strong enough to matter it burns roots and soil life alike. Root rot comes from waterlogged soil — fix the drainage and ease off the watering; that's what actually saves the roots.

Question 35

You must rotate every crop to new ground every single year.

Accepted Answer

You don't have to rotate everything every year — intervals are family- and pathogen-specific. This corpus keeps the ones with real mechanisms (tomatoes ~3 yr, cucurbits 2-3, brassicas 4-7); a yearly shuffle of a low-pressure crop buys nothing, and perennials must never be rotated.

Folklore, checked