How long to wait after pesticide spray on vegetables

Weed killer (herbicide) can be an effective way to get rid of any unwanted plants you may have growing in your yard, but weed killer is normally made up of pretty potent chemicals. These chemicals may not be something you wish to have contaminating plants, especially fruit and vegetables. So the questions “How long does weed killer last in the soil?” and “Is it safe to eat food grown in spots where weed killer has been sprayed previously?” can come up.

Weed Killer in Soil

The first thing to realize is if the weed killer was still present, chances are your plants would not be able to survive. Very few plants can survive a weed killer chemical, and the ones that do are either genetically modified to do so or are weeds that have become resistant. Chances are, the fruit or vegetable plant you are growing isn’t resistant to weed killer, or most herbicides in general. Many weed killers are designed to attack the plant’s root system. If weed killer was still present in the soil, you would not be able to grow anything.

This is why most weed killers are designed to evaporate within 24 to 78 hours. This means that for the most part, it is safe to plant anything, edible or non-edible, in a place where you have sprayed weed killer after three days. If you want to be extra sure, you can wait a week or two before planting.

In fact, the majority of residentially sold weed killers are required by law to break down in the soil within 14 days, if not sooner. Take glyphosate, for example. This post-emergent, non-selective herbicide generally breaks down within days to weeks depending on the specific product you have.

(NOTE: New research has indicated that glyphosate may, in fact, remain in the soil longer than initially thought, up to at least a year. It is best to avoid use of this herbicide if at all possible unless absolutely necessary – and then only with caution.)

Weed Killer Residue Over Time

While all herbicide residue degrades over time, it is still dependent on several factors: climatic conditions (light, moisture, and temp.), soil and herbicide properties. Even if there are some residual, non-plant lethal chemicals left in the soil after the weed killer has evaporated or broken down, these chemicals most likely will have been leeched away after one or two good rainfalls or waterings.

Still, it can be argued that these chemical herbicides linger in soil well beyond a month, or even years, and it is true that residual sterilants, or “bare ground” herbicides, remain in the soil for long periods. But these stronger weed killers are normally limited to agricultural specialists and professionals. They are not meant for home use around gardens and landscapes; therefore, the average homeowner is usually not allowed to purchase them.

For the most part, the chemicals found in weed killers aren’t a problem for the home gardener after they have evaporated. According to many professionals in the field, most of the weed killers used today have a relatively short residual life, as those found to be more potent are typically denied registration by the EPA.

This being said, it’s always a good idea to completely read the directions and warnings on the label of any weed killer or herbicide product you buy. The manufacturer will have provided detailed instructions on how to apply the weed killer and when it will be safe to grow plants in that area again.

Note: Any recommendations pertaining to the use of chemicals are for informational purposes only. Specific brand names or commercial products or services do not imply endorsement. Chemical control should only be used as a last resort, as organic approaches are safer and more environmentally friendly.

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Linda from Melbourne, Fl writes

Bayer Advanced Vegetable and Garden Insect Spray  Pre Harvest intereval all depends on what you are treating. If the label does not state a pre harvest interval, then it can be applied up until the day of harvest. Plesae consult the product label before application. Restrictions:• Pre-harvest Interval: Do not harvest until at least 7 days after application, except for tomato which has no PHI.

• Do not spray more than 6 times per season.

Answer last updated on: 03/13/2014

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By Richard Hoyt Updated November 28, 2018

Sevin, a brand-name pesticide, contains the active ingredient carbaryl. Although it is registered with the U.S. Environmental Protection Agency for use on vegetables, Sevin is toxic and you should exercise extreme caution when you apply it. The manufacturer’s suggested wait time before eating vegetables sprayed with Sevin varies from three to 14 days, depending on the vegetable.

You should not use Sevin or any other chemical pesticide on your vegetables unless you feel there is a clear need. Store Sevin in its original container and out of the way of children and pets. When you use it, wear waterproof gloves, a long-sleeved shirt, long pants, shoes with socks and chemical-resistant headwear. Overexposure can cause a range of symptoms, including blurred vision, breathing difficulty, abdominal cramps, muscle tremors, diarrhea and vomiting. More serious complications range from convulsions and unconsciousness to respiratory failure.

If you get Sevin on your skin or in your eyes or if you inhale or swallow it, call a poison control center or doctor immediately. Have the product container or label with you when you call. Sevin kills bees, so do not spray it on vegetables that are surrounded by blooming plants.

Apply 3/4 to 1 1/2 fluid ounce of Sevin per 1,000 square feet of eggplants (Solanum melongena), peppers (Capsicum spp.), tomatoes (Solanum lycopersicum) and other fruiting vegetables to suppress stink bugs and thrips and to control tomato fruit worms, tomato hornworms, tomato pinworms, lance bugs, tarnished plant bugs, fall army worms, European corn borers and Colorado potato beetles. You may have to repeat the applications once a week for up to seven weeks, but do not apply more than once a week. Apply 1/2 to 1 fluid ounce per 1,000 square feet to control flea beetles and leafhoppers. Apply 1 1/2 fluid ounce per 1,000 square feet to control cutworms. Do not harvest or eat vegetables within three days of application.

The cabbage, or Brassica, family, contains many familiar vegetable plants. Apply 3/8 to 3/4 fluid ounce of Sevin per 1,000 square feet of broccoli (Brassica oleracea), Brussels sprouts (Brassica oleracea "Gemmifera") or cauliflower (Brassica oleracea "Botrytis") to control flea beetles, harlequin bugs or leaf hoppers. Do not eat vegetables for three days. Apply 3/4 to 1 1/2 fluid ounce per 1,000 square feet of cabbage (Brassica oleracea), Chinese cabbage (Brassica rapa ssp. pekinensis and chinensis), collards (Brassica oleracea), kohlrabi (Brassica oleracea) or mustard (Brassica juncea) to control army worms, Astor leafhoppers, corn earworms, diamondback moths, fall army worms, imported cabbage worms, Lygus bugs, spittle bugs, stink bugs and tarnished plant bugs. Do not eat or harvest vegetables until 14 days after application.

You'll have a similar wait for harvesting leafy vegetables. Apply 3/8 to 3/4 fluid ounce of Sevin per 1,000 square feet to control flea beetles, harlequin bugs or leafhoppers on celery (Apium graveolens var. dulce), endive (Cichorium endivia), lettuce (Lactuca sativa), parsley (Petroselinum crispum), spinach (Spinacia oleracea) and other leafy vegetables. Apply 3/4 to 1 1/2 fluid once per 1,000 square feet to control Aster leafhoppers, army worms, corn earworms, Lygus bugs, spittlebugs, stinkbugs, tarnished plant bugs, fall armyworms or imported cabbageworms. Do not eat or harvest vegetables for two weeks.

Quick FAQs are intended to be short, quick answers to frequent pesticide questions. If you don't see your question listed here, try the Common Pesticide Questions section of the website, where you will find fictional stories about people and their pesticide dilemmas. You may also want to try our Fact Sheets, or give us a call at 1-800-858-7378, toll-free from 8:00am - 12:00pm Pacific Time (11:00am - 3:00pm Eastern Time).

Frequent Pesticide Questions

Still not finding answers to your questions? An additional resource might be the Environmental Protection Agency (EPA) Office of Pesticide Programs web page containing answers to frequent pesticide questions. You can also contact a NPIC pesticide specialist for assistance.

1. Is this product safe?

"Safe" means something different to everyone. All pesticides have some level of toxicity, just as every substance does. Even the least-toxic products can cause health problems if someone is exposed to enough of it. The risk of health problems depends not only on how toxic the ingredients are, but also on the amount of exposure to the product. One measure of product toxicity is the signal word. For help comparing different products, call NPIC and talk to one of our pesticide specialists. We'll ask you about your specific concerns, and give you ideas about how to minimize your risk.

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2. If I use this product, will it harm my children or pet?

All pesticides have some level of toxicity. The risk to your children or pet depends on the product toxicity and the amount of exposure. Refer to the "Precautionary Statements" on your product label, including the section of the label called "Hazards to Humans and Domestic Animals" for an overview of the risks. Call NPIC for more information. Be sure to read the entire label before using a product and follow the application directions exactly as written. Those directions are written to minimize the risk of problems and to define the legal uses for the product.

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3. How should I mix and/or apply this product?

Typically, those directions can be found on the product label. Look for the section called "Directions for Use". If you still have questions, or need a copy of the product label, consider talking to the manufacturer of the product. They have expert knowledge of their own product line, so they can probably provide you the specific information you require. If you need help finding the phone number for the manufacturer of your product, call NPIC at the number below for assistance.

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4. Can I use mothballs or moth crystals to keep snakes, birds, skunks or mice out of my house?

Mothballs and moth crystals contain high concentrations of insecticides designed to off-gas to repel pests. Most often, mothballs are only allowed to be used in sealed containers that allow the fumes to build up to a level that kills clothes moths while preventing the fumes from entering living spaces inhabited by humans or pets. Inhaling the mothball fumes can cause health problems. Read the product label for specific instructions on safe handling and use. Click here to learn about the proper use of moth balls.

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5. What is the least-toxic method of controlling this pest?

Integrated Pest Management (IPM) is an environmentally sensitive approach to pest control that relies on identification of the pest, understanding of what the pest needs to survive and reproduce, as well as the various methods of controlling the pest (biological, mechanical, or chemical) with emphasis on using the least-toxic methods first. The fact sheets we linked from our website emphasize an IPM approach to managing pests in your local area. If you need to select a pesticide, consider the Directory of Least-Toxic Pest Control Products from the Bio-Integral Resource Center or read about how Signal Words can be used as indicators of product toxicity.

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6. I think my dog ate some pesticide, what should I do?

If your pet is unconscious, bleeding, having difficulty breathing, or having seizures (shaking, stumbling), consider taking your pet immediately to a veterinarian for emergency medical care. For other situations, contact a veterinarian or NPIC for assistance. We can help by assessing your unique situation and providing information to help you decide on the best course of action. After business hours, consider contacting the National Animal Poison Control Center at 1-888-426-4435; there may be a fee for their services.

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7. How long after applying a pesticide to my garden do I need to wait before eating the vegetables?

Some pesticides can be used on the day of harvest, while others can only be used long before harvest. The time between application and harvest is called a "harvest interval," and it's necessary to allow pesticide residues to decrease to acceptable levels. Check the label directions for the specific plant you are treating to find the harvest interval. Most often, the harvest interval is different for different plants or crops, so it's important to read the entire label carefully. Remember, the label is the law.

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8. Will this product be effective against my pest?

If you do not see a particular pest (bugs, weeds, fungi, etc.) listed on the product label, the product may not be effective against that pest. Consider products that specifically list the pest you're trying to control on the label. Pests can become resistant to some pesticides after repeated use. To find out which products work on the pests in your area, or for help identifying your pest, try talking to your local Cooperative Extension Service. If pesticides haven't worked so far, another pesticide may not be the best solution to your problem. You may want to consider using an integrated pest management (IPM) approach that includes steps such as sanitation, exclusion, prevention and other habitat changes that could be even more effective than pesticides. To learn more, read fact sheets about pests in your area or contact the Bio-Integral Resource Center for advice on controlling pests using an IPM approach.

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9. Can I use this pesticide in my organic garden?

The term "organic" has many meanings. Typically, "organic" pesticides are products that meet the USDA Organic Standard, which means they do not contain prohibited synthetic chemicals. In some cases, people refer to pesticides containing natural extracts of plants as "organic" products. However, to meet the USDA standard, even the "inert" or "other" ingredients in the product must be considered. Call NPIC, contact your organic certifier, or visit our website information on organic agriculture for more information.

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10. Are natural (botanical) products safer than other products?

Natural (botanical) products, like plant oils, are sometimes low in toxicity; however, this is not always the case. Some plant extracts are just as toxic or even more toxic than similar synthetic pesticides. Always handle pesticide products with care and follow the label directions. For help assessing the risks associated with a botanical or natural product, call an NPIC pesticide specialist.

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If you have questions about any pesticide-related topic, please call NPIC at 1-800-858-7378 (8:00am - 12:00pm PST), or email at .

Last updated March 10, 2021

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NPIC provides objective, science-based information about pesticides and pesticide-related topics to enable people to make informed decisions. NPIC is a cooperative agreement between Oregon State University and the U.S. Environmental Protection Agency (cooperative agreement #X8-83947901). The information in this publication does not in any way replace or supersede the restrictions, precautions, directions, or other information on the pesticide label or any other regulatory requirements, nor does it necessarily reflect the position of the U.S. EPA.