The Dirty Dozen & Clean Fifteen Explained: Which Fruits & Vegetables Should You Buy Organic?

Organic produce is wonderful, but if you’re anything like me, buying everything organic simply isn’t realistic.

The good news is that you don’t have to.

Some fruits and vegetables consistently carry higher pesticide residues than others, while many are surprisingly low. Knowing the difference can help you make informed choices and spend your grocery budget where it matters most.

I like to think of it as being intentional rather than perfect. Eating plenty of fruit and vegetables whether they’re organic or conventionally grown is one of the best things you can do for your health. This guide simply helps you prioritise where buying organic may have the biggest impact.

What Are the Dirty Dozen?

Each year, the Environmental Working Group (EWG) in the USA analyses thousands of fruit and vegetable samples for pesticide residues after they’ve been washed or prepared as consumers normally would.

The Dirty Dozen is a list of produce that tends to have the highest pesticide residues remaining after normal preparation. While the data comes from the United States, it’s still a useful guide because many of the same crops are grown using similar farming practices around the world. New Zealand farming does differ in some ways, but the overall trends are often similar and much of our produce is also imported from around the world.

If your budget allows, these are generally the best fruits and vegetables to buy organic.

The Dirty Dozen

• Strawberries
• Spinach
• Kale, collard and mustard greens
• Grapes
• Peaches
• Pears
• Nectarines
• Apples
• Bell peppers and hot peppers
• Cherries
• Blueberries
• Green beans

Many of these foods have thin skins, soft flesh or leafy surfaces so the are more heavily treated with pesticides. Their soft skins also make it more difficult to remove pesticide residues completely and often we eat them without peeling.

What Is the Clean Fifteen?

The Clean Fifteen is the opposite list. These fruits and vegetables consistently test with the lowest pesticide residues.

Many have thick peels that naturally protect the edible portion of the fruit or vegetable, while others simply require fewer pesticide applications during growing.

The Clean Fifteen

• Avocados
• Sweet corn
• Pineapple
• Onions
• Papaya
• Sweet peas (frozen)
• Asparagus
• Honeydew melon
• Kiwifruit
• Cabbage
• Watermelon
• Mushrooms
• Mangoes
• Sweet potatoes
• Carrots

These are the items I’m usually happy to buy conventionally.

Does This Apply in New Zealand?

This is one of the most common questions, and the short answer is yes with a few important differences.

The Dirty Dozen and Clean Fifteen are based on testing carried out in the United States, so they aren’t a direct reflection of New Zealand grown produce. However, they’re still a useful guide because many of the same fruits and vegetables face similar pests and diseases and are grown using comparable farming practices and not to forget mentioning we import large amounts of our produce!

In New Zealand, the Ministry for Primary Industries (MPI) carries out food residue monitoring on selected locally grown and imported foods and sets legal maximum residue limits for pesticides. Independent organisations have also conducted their own testing and have called for broader monitoring of some chemicals and crops.

While our monitoring system differs from the US programme, there isn’t currently an official New Zealand equivalent of the Dirty Dozen and Clean Fifteen but you can still use this as a very reliable guide for our own produce here.

Rather than treating these lists as strict rules, I see them as a helpful way to prioritise where buying organic may give you the greatest benefit if it fits your budget.

What About Bananas?

Bananas don’t usually appear on the Clean Fifteen list, but they’re still considered one of the safest conventional fruits to buy.

Because you remove the thick peel before eating, very little pesticide residue reaches the fruit itself. While bananas can require pesticide use during farming, the edible portion is well protected.

If you’re trying to stretch your grocery budget, bananas are generally a great choice to buy conventionally.

Where Does Broccoli Fit?

Broccoli sits somewhere in the middle.

It can be treated with pesticides during growing, including some systemic pesticides, but it doesn’t usually test with residue levels as high as leafy greens or berries.

If organic broccoli fits your budget, that’s a great option. If not, conventional broccoli is still an incredibly nutritious food and one I wouldn’t stress about buying.

What About Potatoes?

Potatoes are another vegetable that sits somewhere in the middle.

Because they grow underground, they’re naturally protected from many insect pests. However, they’re also susceptible to fungal diseases, so conventional potato crops are often treated with fungicides during the growing season. Some potatoes may also be treated after harvest to help prevent sprouting during storage.

The good news is that potatoes don’t consistently rank among the highest residue fruits and vegetables like strawberries, spinach or apples. If you’re trying to prioritise your grocery budget, I’d focus on buying organic versions of the Dirty Dozen first before worrying about potatoes.

If organic potatoes fit your budget, they’re a great choice. If not, conventional potatoes are still a nutritious and affordable staple that can absolutely be part of a healthy diet.

What About Grains?

Grains are a little different from fresh fruit and vegetables because they’re usually processed before we eat them.

Some conventionally grown grains, such as wheat, oats and barley, may be treated with pesticides during the growing season. In some countries, certain grain crops may also be sprayed with a herbicide before harvest to help them dry evenly, although farming practices vary between countries and crops.

In New Zealand, maximum residue limits are set by the Ministry for Primary Industries (MPI) and are reviewed over time as international standards change so if reducing pesticide exposure is a priority for you, choosing organic grains can be a worthwhile option particularly for foods you eat regularly, such as oats, flour, rice or breakfast cereals.

That said, if your grocery budget is limited, I’d still prioritise buying organic versions of the Dirty Dozen fruits and vegetables before switching all of your grains to organic. For most people, that approach is likely to have a greater impact while keeping food costs manageable.

Green Goddess wrote a blog post recently on this topic and showed that independent testing on our NZ fave Weet-Bix came back with no detection of glyphosates so this is a safer non organic cereal option.

Can You Wash Pesticides Off?

The answer is both yes and no.

Some pesticides remain on the surface of fruit and vegetables and can be reduced by washing thoroughly under running water.

Others are called systemic pesticides, meaning they’re absorbed into the plant while it’s growing. These move through the stems, leaves or fruit itself and can’t simply be washed away.

The good news is that the Dirty Dozen and Clean Fifteen already account for this. The produce is tested after it’s been washed or prepared the way consumers would normally eat it, so the rankings reflect the pesticide residues that typically remain including systemic pesticides.

Should You Be Worried?

For most people, there’s no need to panic.

Food safety authorities set maximum residue limits with large safety margins, and the vast majority of conventionally grown produce falls within those limits.

At the same time, many people choose to reduce their overall pesticide exposure where they can, especially for foods that consistently test higher for residues. If that sounds like you, using the Dirty Dozen and Clean Fifteen as a guide is a practical way to make informed choices without feeling like you need to overhaul your entire grocery shop.

My Simple Rule

If I’m choosing where to spend a little extra on organic produce, I prioritise:

• Strawberries
• Spinach
• Grapes
• Apples
• Blueberries
• Capsicums
• Pears

For foods like bananas, avocados, onions, cabbage, carrots, sweet potatoes and kiwifruit, I’m generally happy to buy conventional.

For everything else, I simply grow it myself or weigh up the price, what’s in season and what’s available

To me, it’s about making thoughtful choices that fit your budget rather than chasing perfection.

Frequently Asked Questions

Is organic produce completely pesticide free?

No. Organic farmers can still use certain naturally derived pesticides, but the number of approved substances is much smaller than those allowed in conventional farming.

Are pesticides inside fruit and vegetables?

Some are. These are known as systemic pesticides because they’re absorbed into the plant during growth. They can’t be removed by washing.

Is New Zealand produce different?

New Zealand has strict food safety standards and monitoring programs. While pesticide use varies depending on the crop, climate and growing methods, the Dirty Dozen and Clean Fifteen are still a helpful guide for deciding where buying organic may make the biggest difference.

Is washing fruit and vegetables enough?

Washing under running water helps remove dirt, bacteria and many surface pesticide residues. However, it won’t remove systemic pesticides that have been absorbed into the plant.

What’s the best approach if I can’t afford to buy everything organic?

Focus on buying organic versions of the Dirty Dozen when you can, and don’t worry about buying conventional options from the Clean Fifteen. It’s a practical, balanced approach that helps reduce pesticide exposure while keeping your grocery budget realistic.

At the end of the day, the healthiest diet is one that’s full of fruits and vegetables whether they’re organic or conventional. Small, intentional choices add up over time, and you don’t have to do everything perfectly to make a positive difference.