Digging for Truth

Sorting fact from fiction in the garden

DID YOU know that you can change the color of hydrangea blooms with pickle juice? Have you heard that crushed eggshells will prevent blossom-end rot on tomatoes? Over the years I've heard plenty of gardening lore like this. But because I'm a reporter and a gardener, I want to know what the facts are. So here's my fact-checked list of homegrown wisdom.

True or not?
Traps are the best way to control Japanese beetles
Shiny green Japanese beetles are a scourge in many parts of the country: They eat flowers, buds and leaves, and — like gardeners — they find roses particularly attractive. Meanwhile, the fat white beetle grubs eat the roots of turf grasses, which makes lawns vulnerable when rainfall is scarce. Eliminating Japanese beetles and grubs is impossible, however. The best strategy is to limit the damage.

Traps capture hundreds of Japanese beetles — especially those with a double-bait system (both a floral lure and a pheromone lure) — but they also attract more beetles to your garden. So if you're using a trap, place it away from the roses and other plants Japanese beetles favor. Ideally the trap is upwind from the site you want to protect — at least 10 feet away.

Small-space gardeners should consider other options. Hand-picking works if you stay on top of it, or try spraying with pyrethrins, which are effective for up to two weeks.

As with many garden pests and diseases, there is no simple solution. You need a strategy that includes grub control, trapping, and planting less-vulnerable species of garden plants, such as boxwood, lilac, hostas and lantanas. For more ideas, read Solutions for Japanese Beetle Control.

Blue and pink hydrangeas

By manipulating the pH of your soil, you can sometimes change the color of hydrangeas.

True or not?
You can change the color of your hydrangeas.
Like many things in gardening, the answer starts with "It depends ..." Nature determines the hue — pink or blue — of mophead hydrangea flowers: More acidic soil produces heavenly blue blooms, and more alkaline (but still slightly acidic) soil produces pink flowers. My grandmother used to pour pickle juice around her hydrangeas to make the flowers bloom blue, but it wasn't her pickle recipe that did the trick. In acid soils, plants absorb naturally occurring aluminum, according to the hydrangea experts at Bailey Nurseries. It's the aluminum that makes the flowers blue.

Pickle juice, coffee grounds, and other home-grown strategies for changing the soil's acidity are not as reliable as easy applications of sulphur (for blue flowers) or lime (for pink flowers), which can be worked into the soil at planting time or around existing plants before they bloom.

Your soil's natural acidity may complicate things. If it tends to be alkaline, it will be difficult to get blue blooms, even with applications of sulphur (and pickle juice). To learn whether your soil is acidic or alkaline, do a pH test. And if you've got to have blue, but your soil is alkaline, try this: Grow hydrangeas in a pot or a planter, where you can start with fresh potting mix and amend it for more predictable results.

True or not?
If you want to attract hummingbirds, put red nectar in the feeder
When hummingbirds visit a garden, they're looking for brightly colored, tube-shaped flowers. They notice red and orange flowers, especially, but also yellow, pink and purple blooms. The nutrient-rich nectar they sip from bee balm, salvias, trumpet vines and other flowers isn't colorful, though — it's clear, and the nectar in hummingbird feeders should be clear, too.


A hummingbird sips clear nectar from the Pressed Glass Hummingbird Feeder.

Red food coloring in hummingbird nectar might be harmful to hummingbirds, according to the Cornell Lab of Ornithology. Honey is also unsuitable for hummingbirds, Cornell experts say. A pretty hummingbird feeder right outside a window or on a porch, filled with a simple nectar made with sugar and water or a nectar mix, will delight hummingbirds and bring them back.

Another way to attract more hummingbirds: Set up more than one feeder. Hummingbirds are territorial and will chase the competition from a favorite nectar source. The more feeders you have, the more hummingbirds you're likely to attract. To learn more, read the article Attracting Butterflies, Hummingbirds and Other Pollinators.

True or not?
Crushed eggshells can prevent blossom-end rot
Tomatoes, eggplants, peppers and melons are susceptible to blossom-end rot, which shows up as leathery brown or black patches on the blossom end of fruit. Blossom-end rot develops when a plant's need for calcium exceeds what it can draw from the soil. Adding crushed eggshells, which are rich in calcium, will limit the damage caused by blossom-end rot, according to the National Gardening Association. When you transplant seedlings into the garden, mix crushed dried eggshells from a dozen eggs around the roots of each tomato plant; that should provide all the calcium the plants need. Another technique: crush a few calcium carbonate tablets and water the powder into the soil.

However, the most efficient approach is to use fertilizer with added calcium. Not only do your plants get needed calcium, they get other nutrients that encourage vigor and abundant fruiting. Over-fertilizing may also cause blossom-end rot because plants grow so quickly that they can't take up enough calcium from the soil. Be sure to apply at the recommended rate.

Blossom-end rot can also be brought on by excessive dryness or moisture fluctuations, so be consistent in your watering routine, adjusting as needed to account for rainfall.

Tomato fertilizer

This fertilizer with calcium is especially formulated for tomatoes.

So if you want to use eggshells, go for it. But remember that your best defense against blossom-end rot includes consistent watering, adequate fertilizing, and mulching to preserve moisture in the soil. Ohio State Extension researchers recommend one inch of moisture a week, from rain or irrigation. A soaker system on a timer will help, but remember that too much moisture can be just as bad.

True or not?
Tomatoes must be staked or supported
You can grow tomatoes just fine without staking the vines or enclosing them in cages. However, tomato supports make sense for many reasons.

  • Fruit is easier to harvest.
  • Tomatoes ripen above the soil surface, where there's less chance for rot and damage from slugs and other pests.
  • Air circulation is better, which helps prevent some diseases.
  • Cages are efficient: According to researchers at Texas A&M University; tomatoes grown in cages do not need to be pruned or tied. The plants grow large and bushy, and their abundant foliage protects fruit from sunburn and birds.

More Like This

For more gardening myths and truths, check out a blog called Garden Professors, which is dedicated to science-based gardening information.

Because they are more compact than cages, some gardeners prefer stakes. If you use them, pinch off suckers to create plants with a single, stakeable stem. Using pieces of cloth or soft tomato ties, secure the main stem to the stake at 12-inch intervals. You're likely to harvest fewer tomatoes than plants grown in cages, but, the fruit will probably be larger. It might even ripen earlier.

Tomato Cage

A Tomato Cage keeps vines off the ground and makes harvesting easy.

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