How to Deal with Pests in Herb Gardens
Believe it or not, many herbs are pest-free, which is one of the reasons gardeners find these plants so easy and fun to grow. Some herbs even repel pests from themselves as well as adjacent plants. However, you may meet a handful of pests in your herb garden. If you do, act quickly to rescue your harvest, either by treating the plant or by tearing it out and getting rid of it before the problem can spread.
Check out the following table for a rap sheet of the major troublemakers.
Pests and the Herbs They Dine On
| Pest |
Appearance |
Effect on Plant |
Food Preference |
| Aphids |
Tiny sucking insects that congregate in groups; they may be
white, greenish, or black |
A severely infested plant turns yellow and dies. |
Caraway, lovage, nasturtium, and oregano |
| Carrot weevil |
A tiny, hard-shelled brownish bug |
Carrot weevils attacks the root as well as the top of the
plant. |
Parsley |
| Japanese beetle |
Green and copper colored bugs |
These bugs are voracious foliage eaters. |
Basil and echinacea |
| Leaf miner |
A bug that starts as a tiny yellowish larvae and turns into
small, black fly with yellow stripes |
Affected leaves have meandering tunnels and blotches. |
Lovage, oregano, and sorrel |
| Scale |
Bugs that look like small waxy or cottony bumps |
Scales feed by sucking sap, and they leave behind telltale
honeydew (which, in turn, attracts ants and sooty mold). |
Bay, myrtle, and rosemary |
| Slugs and snails |
You know these slimy characters! But you may not always see
them — they're most active at night |
Slugs and snails devour foliage. |
Basil, calendula, and sorrel |
| Spider mite |
A wee relative of the spider |
Spider mites suck plant juices, leaving telltale pinprick spots
and puckering. |
Angelica, germander, lemon verbena, mint, oregano, rosemary,
sage, and thyme |
The pests that go after herbs may seem as varied as the herbs themselves, but here are a few defensive strategies you can take to protect your herbs:
Make sure your herbs are in good health, well-watered, and in particular have sufficient elbow room.
Remove affected leaves; pull out severely infested plants and throw them away before the problem spreads.
Dislodge small infestations with a spray from the hose; larger insect pests may be hand-picked and destroyed.
If you have to spray, try insecticidal soap, which is nontoxic. Make sure the pest you're targeting is listed on the label, and then carefully follow the directions regarding how and when to apply.
You can combat certain pests with beneficial insects, such as ladybugs or lacewings.
If you succeed in beating back a pest and later want to use the herb for fresh eating or to cook it, be sure to wash it thoroughly first!
Gardening Glossary
annuals
Plants that complete their entire life cycle within one growing season. The plant germinates from seed, grows and blooms, and then produces seed and dies.
Gardening Glossary
biennials
A plant that take two growing seasons to complete its life cycle. It germinates and grows leaves and stems in the first year; produces flowers and fruit (seed) in the second, and then dies.
Gardening Glossary
bolt
When a plant flowers or produces seed prematurely.
Gardening Glossary
cold frame
A wooden or concrete block box in which you can grow plants or hold dormant during the cold winter months.
Gardening Glossary
cole crops
A family of vegetables, including broccoli, cabbage, cauliflower, kale, and Brussels sprouts. They thrive in cooler weather.
Gardening Glossary
complete fertilizer
Any fertilizer that contains all three of the primary nutrients, N-P-K (nitrogen, phosphorus, potassium). Phrase is based on regulations governing the fertilizer industry. Does not mean that the fertilizer literally contains everything a plant needs to thrive.
Gardening Glossary
deadheading
The practice of pinching or cutting off spent flowers
Gardening Glossary
evaporative-pad humidifier
A humidifier in which fans blow across a moisture-laden pad that sits in a reservoir of water.
Gardening Glossary
harden off
The process of acclimating plants grown indoors gradually to the brighter light and cooler temperatures of the outside world.
Gardening Glossary
hardiness
The ability of a plant to survive is called its hardiness.
Gardening Glossary
humus
A stable end product of organic-matter decomposition that's believed to increase microbial activity in soil, improve soil structure, and enhance the root development of plants.
Gardening Glossary
Bacillus thuringiensis Bt
An effective bacteria that attacks only the larvae of caterpillar family insects. It is safe to other insects, animals, and humans.
Gardening Glossary
macronutrients
Mineral nutrients that plants need in the largest quantities: nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.
Gardening Glossary
mulch
Organic or inorganic material placed over the surface of soil, usually directly over the root zone of growing plants. Used to conserve moisture, kill weed seedlings, modify soil temperature, provide attractive covering to garden beds.
Gardening Glossary
organic matter
Once-living stuff like compost, sawdust, animal manure, ground bark, grass clippings, and leaf mold (composted tree leaves). Used to enrich soil and improve soil texture.
Gardening Glossary
perennials
Any plant with a life cycle of three or more years. Herbaceous (non-woody) perennials include flowering plants and herbs, mainly. Woody perennials include trees and shrubs. Longevity depends on the plant and growing conditions.
Gardening Glossary
pH
The measure of soil's acidity. Soil with low pH means it's too acidic; soil with high pH means it's alkaline. Most plants grow best in soil with a pH value between 6.5 and 7.2. Neutral soils measure 7.
Gardening Glossary
photosynthesis
The process through which plants take nutrients from the air and from the water in the soil to produce sugars that fuels the plant's growth.
Gardening Glossary
primary nutrients
Nitrogen, phosphorous, and potassium are the three nutrients plants need in the largest quantities.
Gardening Glossary
root crops
Plants with edible underground roots such as onions, carrots, beets, potatoes, turnips. Most root crops are cold-weather crops.
Gardening Glossary
self-blanching
A type of cauliflower with leaves that naturally curl over the head and exclude light. Requires cool temperatures for leaves to curl effectively.
Gardening Glossary
sets
Small onion bulbs, about 1/2-inch wide, that were started from seed the previous year. Grow onion sets with the pointy end up.
Gardening Glossary
side-dressing
The act of adding a small amount of fertilizer around or "on the side" of plants after they're growing.
Gardening Glossary
succession planting
Planting small, 2-to-4-foot patches of plants every two weeks throughout the growing season so that you can harvest a crop over an extended period of time.
Gardening Glossary
thinning
The act of cutting the least robust seedlings in your garden to give the healthier plants more room to grow.
Gardening Glossary
vining crops
Crops that grow on vines, such as cucumbers, melons, pumpkins, and winter squash. They usually require support (staking, trellising, etc.) to keep them off the ground.
