Explore tips for beginning gardening and learn about the typical vegetable garden myths many beginners mistakenly believe.
There are as many garden myths as there are types of sweet corn. And while the lure to believe these myths is tempting, falling for them won’t help your crops.
Beginning Gardening Basics: Debunking Vegetable Garden Myths
Let’s look at a few common gardening misconceptions and explore what’s actually going on behind them. Don’t worry if you fell for one of them – we won’t tell.
I believed this one for far too long. The myth holds that water droplets act like a prism (imagine children torturing ants with a magnifying lens) and concentrate the sun’s energy. If your plants are droopy, give them a drink.
Watering on Sunny Days Will Sunburn Leaves
In nature, sunshine often follows summer rain – daily in some regions, and the plants aren’t harmed. In fact, they’ve evolved to thrive in these conditions. However, watering during daylight is less effective, as some water evaporates before soaking in. If you can, water in the early morning to prepare your plants for the day’s heat. Morning watering also lets your leaves dry quickly in the daylight, which can help minimize fungal problems. It’s also worth the effort to implement systems, such as soaker hoses, that water just the base of your plants instead of sprinkling the whole garden.
Add Sand to Loosen Heavy Clay Soil
On the spectrum of soil particle size, sand is at one end and clay is at the other. You can mix them together to get something in the middle, right? Please don’t.
Mixing sand and clay won’t improve drainage nor loosen heavy soil. It can become a nightmare strongly resembling concrete. Rototilling makes it worse by breaking up air pockets.
Instead, add lots of organic material to your soil. Compost is great. Uncomposted leaves, grass clippings, and pine needles also help. Work them in with a soil fork, or layer them thickly and let your soil’s microbial life do the work.

Marigolds Repel Pests
Marigolds repel some pests. Research recommends French or African marigolds, either as a cover crop before your garden crops go in, or planted alongside your crops. The marigolds can help reduce soil populations of root-knot nematodes, a common pest that weakens crop plants. However, marigolds aren’t a cure-all, and the beneficial effects aren’t long-lasting.
What about bigger pests? For years, I planted marigolds to repel rabbits. While the pungent scent of a disturbed marigold can put off a browsing deer – if they aren’t too hungry – rabbits seem to just go around them. Fencing is a better option.
Roly-Polys Only Eat Dead and Decaying Material
Roly-polys, Armadillidium vulgare, also known as “doodle bugs,” “pillbugs,” “potato bugs,” or “woodlice,” are terrestrial crustaceans that mainly eat dead and decaying organic matter in the soil. However, they happily damage young plants, such as cucumbers, strawberries, tomatoes, radishes, lettuce, peas, and beans, as well as ornamentals. They can also munch on ripening melons.

If you have issues with roly-polys, try removing the mulch and let the soil dry for a bit. Roly-polys need moist environments because they breathe through gills. When the plants are larger, reapply mulch as needed. Placing melons on platforms will keep them safe. Vertical trellises or using neem oil can help too.
Epsom Salts Are a Must for Great Tomatoes
Though salts are often touted as a cure for blossom end rot, it’s due to a calcium deficiency (not a lack of magnesium), and it’s usually caused by uneven soil moisture inhibiting calcium uptake by the plant.
Epsom salts contain magnesium sulfate. Too much magnesium can inhibit plants’ uptake of calcium and other nutrients. If you suspect a magnesium or calcium deficiency, get a soil test first. Sprinkling random remedies can do more harm than good, and it’s hard to fix if you get it wrong. Your best bet is to keep your soil evenly moist.

Nothing Grows Under a Walnut Tree
The black walnut tree, Juglans nigra, has a bad reputation for suppressing any growth underneath its canopy. You may have heard about the chemistry: Walnuts exude a chemical called hydrojuglone, which turns to juglone when exposed to air. Juglone is toxic to many plants, thereby reducing competition for the walnut, a survival strategy called allelopathy.
Although the effects of juglone on other plants have been examined in lab studies, there’s surprisingly not much field research to convincingly link plant survival or growth to juglone levels in the soil. The list of things that can and can’t be grown under walnuts seems to be based on observations. For example, tomatoes and their relatives tend not to thrive under walnuts. Squash and Jerusalem artichokes tend to fare just fine.
If you have black walnuts where you’d like to garden, remember they provide valuable habitat and food for wildlife, and the right answer isn’t necessarily to cut them down. Experiment to see what you can grow near and under them.
Many of us have to garden near trees. If they’re part of your gardening landscape, consider growing crops that can tolerate lower light levels. In a mixed landscape, your crops and trees will also compete for water and nutrients in the soil. Compost, mulch, and additional water during dry spells will help.

Cover Newly Pruned Tree Limbs with Varnish, Tar, or Paint
If you cut your finger, you’ll likely cover the wound with a bandage to keep dirt out, then go back to gardening. So, if we cut a tree, it seems common sense to bandage the wound. However, “tree paint” or other products can seal in moisture and decay.
The tree will seal off a properly pruned limb all on its own. Keep your pruning wounds small when possible, and let the tree do its thing naturally.
Bury Rusty Nails to Improve Soil Quality
Nails are made of iron, and plants need iron, right? Sort of. These days, most nails are made of steel, aluminum, brass, and more. However, some (particularly old) nails rust (oxidize) into iron oxide, which isn’t usable by plants. Soil microorganisms are ineffective at changing iron oxide into a plant-usable form, so it just sits there. Plus, iron oxide isn’t something you want large quantities of in your garden, as it can irritate skin and eyes.
Iron deficiencies can cause iron chlorosis, which presents as yellowed leaves with green veins. If you’re noticing this, testing soil pH and iron levels may be worth your time. However, most soils aren’t iron-deficient, and iron is usually present in soluble forms, which plants can take up.
Throw Eggshells Under Plants for a Calcium Boost
Eggshells are high in calcium, and plants need calcium, so this seems like a no-brainer. But eggshells take forever (we’re talking decades) to break down in your soil. Until decomposed into microscopic levels, eggshells won’t benefit your plants, even through the roots.

Don’t give up. Dry eggshells in the oven then use a coffee grinder or similar to create eggshell dust. Once this dust is sprinkled on or mixed into the soil, it’ll break down much more quickly into usable nutrients. Just don’t expect immediate results.
Pine-Needle Mulch Acidifies Soil
Pine trees grow best in acidic soils, but that’s not because the pines made the soil acidic.
While green pine needles are acidic, they’re almost neutral once brown in your yard. Even generously applying green pine needles to your soil wouldn’t make an appreciable difference to the pH level. But use those beautiful pine needles as mulch – they’ll work wonders.
Garlic Won’t Grow if Planted in Spring
This is partially true. We plant garlic in fall because it, like tulips and daffodils, needs vernalization – a cold period – to stimulate flowering and bulbing. Garlic planted late in spring won’t get enough cold soak time and will grow a green top, but often no bulb, or only a weirdly shaped mass below the surface.

If you need to plant garlic in spring, chill it in the fridge first or plant it as soon as the ground thaws enough for planting. If you go the refrigerator route, hardneck varieties will need 6 to 8 weeks of cold, while softneck varieties will need 3 to 4 weeks.
Originally published as “Garden Myths Exposed” in the December 2024/January 2025 issue of MOTHER EARTH NEWS magazine and regularly vetted for accuracy.
Andy Wilcox is a freelance writer and flower farmer who’s passionate about gardening, horticulture, and forestry, and who believes healthy soil leads to healthy people. Visit his website for more information.