Why Does My Lettuce Taste like Dirt? (4 Possible Reasons)


Lettuce is one of my favorite key ingredients in salads but getting them from the store all of the time is a gamble. That’s why I prefer growing my own lettuce, although nobody likes to eat lettuce that tastes like dirt. So why does some lettuce taste like dirt?

Lettuce develops a dirty or earthy flavor due to soil microbes, bacteria, the presence of some bio compounds (like geosmin), being grown in warm or soggy soil, an imbalance in soil nutrients or fertilizers, high soil alkalinity, disease, or improper storage.

So, let’s talk about all of the reasons why lettuce can taste like dirt so that you can grow it properly – so that it only ever tastes like lettuce. Ready? Let’s do this.

An image of the delivery of fresh herbs and salad from the farm's greenhouse. A man Holds a box of lettuce in his hands.

4 Reasons Why Lettuce Tastes Like Dirt

Lettuce can taste like dirt any time there’s one of these issues. Just to recap, those reasons are:

  1. Soil microbes or bacteria
  2. Bio compounds (like geosmin) produced by the microbes
  3. Improper growing conditions for lettuce (soil, water, fertilizers)
  4. Improper storage

There’s going to be a good bit of overlap between the four reasons, but that’s okay. Because they all build on each other in nature, so we have to understand them all together anyway.

Reason #1: Soil microbes or bacteria

Lettuce that has a lot of bacteria growing on it can develop an earthy, dirty taste.

And any time we have soil or fertilizers, we’re going to have microbes or bacteria. Or maybe even a few viruses. That’s normal. Most of us can’t grow our food in a clean room where we keep every single pathogen away from our precious food.

For example, Aster Yellow is a disease in lettuce that can cause infection, bitterness, dirty taste, discoloration, stunted leaf growth, and the deformation of the whole plant.

Some of these microbes are the reason for the dirty taste, though generally the root cause of why the germs cause the dirty taste actually leads us to our second reason, which is bio compounds like geosmin.

Reason #2: Geosmin is present

Geosmin is a bio-compound that is produced in lettuce due to the presence of microbial or bacterial load. Geosmin causes a dirt taste in lettuce, and it’s present as long as the bio compound is there.

Common bacteria, such as E. coli (which are naturally present in both lettuce and soils) may produce geosmin.

If your soil has a high pH (or soil alkalinity is high) also enhances the production of geosmin in the lettuce, leading to a bad smell or earthy taste while eating it. This dirt taste is highly undesirable, and nobody wants it in their salad.

Reason #3: Improper growing conditions affect the flavor

Lettuce needs the right conditions to develop its crunchy, delicious flavor sans the dirty taste. The big issues here are the soil temperature and water levels, though improper fertilization can also affect the flavor.

Warm or soggy soil can naturally affect the flavors of any lettuce or green vegetables being grown. However, most of these foods can’t be grown in cold, dry, or freezing conditions, so it’s important that we learn how to balance the needs of the food with moderation so that they don’t develop a dirty flavor.

Using unbalanced fertilizers, which can lead to soil imbalance, can also be the root cause of the earthy flavor. The excessive use of nitrogen, poor nutrient supplementation and poor water application also produce a bitter, dirty, or earthy flavor in leafy vegetables.

Reason #4: Improper storage conditions

Lettuce needs to be refrigerated in accordance with food handling recommendations to prevent it from growing sufficient microorganisms, or for the microorganisms to produce enough bio compounds that the dirty taste develops.

Usually, this can mean storing it properly in the fridge or eating it fresh, so you don’t have to store it. Thankfully, there are some cool ways to clean and ways lettuce so that you can get rid of the earthy flavor even if it wasn’t stored perfectly for every minute of the day.

Just remember, it’s better safe than sorry. So if you’re ever concerned about the lettuce, toss it so you don’t get food poisoning.

An image of fertilizer pouring into lettuce plants in a vegetable row.

How Do You Get the Dirty Taste Out of Lettuce?

The dirty flavor can be removed from lettuce by changing how it’s grown, washing it properly, and storing it properly before it’s eaten. Adding wood ash to the ground can improve the soil (and remove the dirty flavor from green vegetables) while washing lettuce in vinegar and/or baking soda can remove undesirable flavors.

Thankfully, even if you don’t do everything perfectly (from growing to storing lettuce), there are ways to improve the overall flavor.

There is no special equipment required, but you do need to change some plant feeding practices and wash your lettuce with some organic and safe compounds that you’ve probably already got on hand.

Then, you can see the real change in the lettuce’s taste, crispiness, and freshness within days. And it won’t taste dirty anymore, either. You’ll probably want to experiment to see which of these methods works best for you, though you may also want to combine one of the wash styles with the wood ash trick.

Maybe don’t combine the baking soda and vinegar, though. Not unless you’re wanting to also do a second-grade science experiment at the same time. Remember those baking soda vinegar volcanoes?

Tip #1: Water and wash lettuce with vinegar

Vinegar is a mild, non-toxic, and aqueous solution of acetic acid, containing 5-8% acetic acid by volume.

Now, here’s the fun part. You’re not only going to want to wash your lettuce with vinegar after it’s harvested, but you’re also going to want to add it into your plant’s water before it’s harvested.

Before harvesting, add 1 to 2 ounces of vinegar per gallon of irrigation water to your normal watering routine. Adding vinegar to the water discourages the alkalinity rise up and lowers the geosmin production rate. These steps acidify the soil pH and help the removal of dirty taste from the lettuce.

After harvesting, you can also wash lettuce leaves with diluted vinegar to remove the earthy flavors from the plant leaves.

Here’s how you do that.

  1. Mix cold water and ¼ cup of vinegar (Apple Cider Vinegar works great) in a large bowl.
  2. Peel off the undesirable or discolored lettuce leaves.
  3. Rinse the lettuce leaves with ample cold water from the tap (not the vinegar water) and repeat the steps 2-3 times.
  4. Dip the pre-washed lettuce in the bowl of vinegar water with slow, round movements. The attached microbes and undesirable bacteria will be removed from the lettuce and disinfected per the best food safety and hygiene practices.
  5. Dry the lettuce with a paper towel and place it in an air-tight bag or container.
  6. Store the lettuce in the fridge.

The vinegar treatment not only decreases the geosmin and the microorganisms that produce it but also removes the muddy taste on the lettuce. It also enhances the freshness and crispness of the lettuce.

Pro tip: this same cleaning method can also be used for the other leafy vegetables picked from your garden – or from the store!

Tip #2: Add wood ash to your soil

To remove the effect of excessive nitrogen practices while growing lettuce plants, add a small dose of wood ash to your garden soil. This will make the soil less likely for green vegetables to develop any earthy, bitter, and bad-tasting flavors.

Keep in mind that you shouldn’t add a lot of wood ash to a garden at any time. Keep it small. When in doubt, add the wood ash to compost and let it age. That way, you can keep an eye on things so that you don’t overdo it with the wood ash.

Tip #3: Wash lettuce with baking soda

Baking soda is another great way to remove any bitter or undesirable dirt flavors from lettuce.

  1. Separate the lettuce leaves and rinse them 2-3 times with cold water.
  2. Add a small amount of baking soda to a separate bowl and mix thoroughly with water.
  3. Soak the leaves for 5-10 minutes in baking soda water and rinse with cold water.
  4. Repeat the procedure 2-3 times for the best possible outcome.
  5. Rinse with regular water, then dry with a salad spinner (or pat dry with paper towels) and store in an air-tight container in the fridge for longer shelf life.

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You can also use a veggie wash (like this one on Amazon) if that’s more your style. Veggie washes contain natural, herbal, and organic ingredients like citric oils (which are acidic in nature) that not only remove the bad smell or any bitter flavors but also removes anything like insecticides. 

An image of green lettuce growing in the greenhouse with a drip irrigation system.

Can You Get Sick from Bitter Lettuce?

Lettuce that is bitter due to certain microorganisms, like E. coli, 0157 may cause food poisoning. Lettuce that is properly washed and stored can often remove any disease-causing pathogens, along with the bitter taste. If the lettuce in question has been recalled, though, always follow the recall instructions.

Food recalls of contaminated greens happen, and sometimes it feels like it happens frequently. This can be another reason you’d want to grow your own lettuce. Just make sure you’re always properly washing and storing your own lettuce, though, as the FDA doesn’t test homegrown lettuce to make sure it’s safe for you to eat.

Spoiler: it doesn’t happen a ton. I checked the CDC’s website – there are three listed recalls on their site.

Always follow the “when in doubt, throw it out!” mantra, too.

How Can You Tell When Lettuce Goes Bad?

Lettuce shelf life is considered 7-10 days if stored at optimum refrigerator temperature. Any acrid odor, telltale brown spots, and drooping leaves are the main indications of bad lettuce and active rotting.

Sometimes, if only some leaves look rotten, those can be discarded to keep other leaves safe from spoilage and safe to eat.

Here are some other things to look for so you know if your lettuce has gone bad or not.

  • Throw away lettuce with any brown, black, or fuzzy white patches on the leaves. Rotting leaves may spoil the whole batch of lettuce. Discoloring and back spot indicates that the lettuce is on its way out.
  • Rancid, rotten, and pungent smells are other indicators of lettuce gone bad. If it smells that bad, definitely don’t eat it or feed it to any of your animals.
  • Wrinkling, soft, and droopy leaves are another sign lettuce has gone bad. Sometimes, you can revive mildly droopy leaves with an ice bath. But if that doesn’t work? It’s probably time to retire that bit of lettuce.
  • Wet, slippery, or slimy lettuce isn’t good to eat. If you wouldn’t want to touch the lettuce, you don’t want to eat it.
  • Yellowed, moist, or swollen air-tight containers of lettuce have gone bad. Beads of water will likely appear in the container. This is a good sign it’s turned. The turned lettuce will also produce a nasty and rotten smell.
  • Rotten lettuce will also smell or taste sour, rancid, or unusually strong. Don’t eat it. You’ll wish you hadn’t.

Always follow the “when in doubt, throw it out!” mantra. It can save you some serious issues related to food poisoning. Nobody wants to be sick from eating something that didn’t even taste good.

Important note: if you ever do get sick from eating questionable food, please seek appropriate medical attention.

Next Steps

Now that you know why your lettuce tastes like dirt (and how to fix it), make sure you store it properly. Lettuce is one of the foods that I don’t like to freeze-dry, mostly because reconstituting is kind of a pain. That being said, maybe you’d like to try it. But first, go read all the reasons why I don’t like freeze-drying lettuce in this article here.

Resources

It’s important to learn from your own experience, but it’s also smart to learn from others. These are the sources used in this article and in our personal research to be more informed as homesteaders.

  • “Carrot-Aster Yellows.” Utah State University Extension, extension.usu.edu/vegetableguide/root-crops/carrot-aster-yellows.
  • Chadwick, M., et al. “Light Quality During Early Seedling Development Influences the Morphology and Bitter Taste Intensity of Mature Lettuce. (Lactuca Sativa) Leaves.” ScienceDirect, 1 Jan. 1996, www.sciencedirect.com/science/article/abs/pii/S0176161711814823.
  • Chadwick, M., et al. “Perception of Bitterness, Sweetness, and Liking of Different Genotypes of Lettuce.” ScienceDirect, 15 Apr. 2016, www.sciencedirect.com/science/article/abs/pii/S0308814615301035.
  • “Reports of Selected E. Coli Outbreak Investigations | E. Coli | CDC.” Centers for Disease Control and Prevention, www.cdc.gov/ecoli/outbreaks.html.

That CDC link above takes you to the page where the CDC lists known outbreaks. It may be a good one to bookmark if you’re ever concerned about food-borne illnesses from store-bought foods.

An image of Kimberly and her daughter gardening

About Us

I’m Kimberly Starr. My family has always loved being outside and gardening. Now we are building a backyard homestead and immersing ourselves in this wonderful new lifestyle. We’re learning as we go what works and what doesn’t. This website is where we’re sharing everything we’ve learned.

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