Why can you eat white watermelon seeds but not black ones?

Watermelons come in a variety of colors, from the familiar red, to yellow, orange, white and even green. The most common types are red inside with black seeds, or white inside with white seeds. Many people are familiar with the urban myth that eating black watermelon seeds will cause a watermelon to grow in your stomach, while white seeds are fine to eat. Is there any truth behind this myth? Let’s take a look at the science and history behind watermelon seeds.

Why Do Watermelons Have Seeds?

Like all fruits, watermelons contain seeds which are necessary for the plant’s reproduction. Watermelon seeds develop inside the watermelon fruit from the female flower once pollinated. The seeds contain a hard outer coating called the husk or shell which protects the seed as it grows.

Watermelon seeds come in two main colors – white or black/brown. This coloring is determined by genetics. Early watermelons all contained white seeds, while black seeds developed later. Most modern red watermelons contain black seeds, while white seeds are more common in yellow or orange types. The color difference is only skin deep – internally the seeds contain the same genetic material needed to grow new watermelon plants.

Are Black Watermelon Seeds Poisonous?

There is no scientific evidence that black watermelon seeds are toxic or dangerous to eat. Like other edible seeds such as pumpkin or sunflower, watermelon seeds contain fats, proteins and micronutrients. In fact, watermelon seeds are nutritious – 1 oz of dried watermelon seeds contains:

Nutrient Amount
Calories 158
Fat 14g
Protein 6g
Carbs 5g
Fiber 1g
Manganese 19% DV
Phosphorus 12% DV
Copper 12% DV
Magnesium 11% DV

The myth that black watermelon seeds are dangerous likely comes from their appearance, as they look harder to chew and digest than white seeds. However, there is no toxic compound or substance inside black watermelon seeds that would make them inedible.

Are White Watermelon Seeds More Nutritious?

While white and black watermelon seeds are very similar internally, some research has found nutritional differences between the two seed types.

In a 2017 study, white watermelon seeds were found to contain higher levels of protein, fat, fiber and ash than black seeds. White seeds also had higher concentrations of many essential amino acids, minerals like magnesium, potassium and phosphorus, and phytochemicals like flavonoids.

These differences may be due to factors like the melon variety, growing conditions and stage of ripeness. But in general, published research suggests white watermelon seeds may be more nutrient dense than black seeds.

However, both types of seeds are nutritious in their own right. So the color of the seed should not be a major factor in determining whether or not to eat them.

Are Watermelon Seeds Easy to Digest?

One of the biggest concerns people have around eating watermelon seeds is digestibility. Since the seeds have a hard outer shell, they seem like they would be difficult to break down in the digestive system.

In reality, the shells of properly chewed watermelon seeds are digestible. The shells are made of cellulose and lignin – compounds found in many plant foods like nuts, seeds, whole grains and produce.

Though rigid, the cell walls in seed shells can be broken down by chewing and the actions of enzymes in the mouth, stomach and intestines. This releases the nutrients inside the seeds so they can be absorbed.

For the best digestibility, watermelon seeds should be chewed well rather than swallowed whole. Soaking or roasting the seeds can also make them softer and the shells easier to break down during digestion.

So while watermelon seeds may seem hard to digest because of their outer shell, the human digestive system is actually well equipped to break them down fully.

Will Eating Watermelon Seeds Make Them Grow in Your Stomach?

The myth that swallowed watermelon seeds will sprout and grow inside someone’s stomach comes from the basic fact that seeds contain new plants inside them. However, the human digestive system is not the right environment for seeds to sprout.

In order for seeds to germinate, they need the right combination of warmth, moisture and soil nutrition. The extremely acidic environment of the stomach destroys seeds, and they pass through the intestines unaltered.

Eaten watermelon seeds may grow if they are passed through stool undigested. But this would only occur in very rare circumstances. Numerous studies have shown swallowed seeds are excreted un-germinated after digestion.

So while watermelon seeds have the potential to sprout and grow under the right conditions, the human digestive tract does not offer those conditions. Swallowing any type of seed is not going to lead to a plant growing inside of you.

Are There Any Downsides to Eating Watermelon Seeds?

Watermelon seeds are generally safe and healthy to consume. However, there are a few things to keep in mind:

– Choking hazard – Whole seeds may present a choking risk for young kids who cannot properly chew hard foods. Seeds can be ground up to minimize this risk.

– FODMAPs – Watermelon seeds contain FODMAPs (fermentable carbs) that may irritate people with IBS.

– Allergies – Those allergic to seeds should avoid watermelon seeds. Cross-reactivity is also possible for people with nut allergies.

– High phosphorus – The phosphorus in watermelon seeds could be an issue for those with chronic kidney disease who need to limit dietary phosphorus.

As long as seeds are chewed up, they should be safe for most people. Anyone with concerns over digestibility or health conditions should exercise caution and talk to their doctor first.

Are Watermelon Seeds Safe to Eat Raw?

Raw watermelon seeds straight from the fruit are perfectly safe to eat. However, any type of raw seed or nut carries a small risk of containing bacteria or aflatoxin mold.

To minimize this risk, raw watermelon seeds are best consumed fresh. Older seeds, or those stored for long periods at warm temperatures, are more likely to spoil and harbor pathogens.

Dried watermelon seeds sold for snacking should come from a trusted producer to ensure proper drying and storage. Check expiry dates and look for signs of moisture or mold.

Proper food safety practices like handwashing are also important when handling any raw seeds or nuts.

As a whole fresh fruit, eating watermelon and its seeds is considered very low risk. But for raw seeds, freshness is important. Roasted or soaked seeds pose less potential risk than raw.

Do You Have to Crack Watermelon Seeds to Eat Them?

While it’s possible to crack open watermelon seeds and just eat the insides, you can safely consume the entire seed.

As mentioned earlier, the outer shell of watermelon seeds is digestible, though quite hard and crunchy. For the easiest digestion, the seeds should be chewed up to break that outer shell rather than swallowed whole.

Cracking the shell before eating makes the seed softer and easier to chew. But it’s not required for safety or nutrition purposes. The intact seed will break down during digestion, it just takes more chewing beforehand.

Some ways to prepare intact watermelon seeds include:

– Boiling – Boiling for 10-15 minutes softens the shell while still keeping the seed intact.

– Baking – Baking at 350°F for 15-20 minutes makes the shell crispy and more brittle for chewing.

– Soaking – Soaking in water for 1-2 hours rehydrates the seed, swells and softens the shell.

– Sprouting – Sprouting or germinating the seeds breaks down the shell over 2-3 days.

Cracking the shells is quicker, but not mandatory. With proper preparation, the whole seed becomes tender enough to chew and digest.

Do You Need to Roast Watermelon Seeds Before Eating?

Roasting brings out more flavor and crunch from watermelon seeds. But it’s not required for palatability or safety. Raw, soaked, sprouted and boiled seeds are all perfectly fine to consume as well.

Here are some pros and cons to roasting watermelon seeds before eating:

Pros of Roasting

– Brings out nutty, savory flavor
– Makes the shell crispy and crunchy
– Allows seasoning to stick better
– Inactivates enzyme inhibitors found in raw seeds that can block nutrient absorption
– Kills bacteria and molds from improper drying or storage

Cons of Roasting

– Takes more time and effort
– Heating can damage some antioxidants and vitamins
– Raw seeds contain probiotics and enzymes
– Can’t eat shells if roasted to very dark or burnt

In general, roasting improves the texture and brings out more roasted flavor. But raw seeds softened by soaking, sprouting or boiling are still perfectly safe and nutritious. Roasting is recommended but not essential.

What’s the Best Way to Roast Watermelon Seeds?

Roasting brings out delicious flavor and crunch in watermelon seeds. Here is a simple roasting method:

Supplies Needed:

– Watermelon seeds – remove from fruit and clean off fruit pulp
– Baking sheet
– Parchment paper
– Spice blend (optional)


1. Preheat oven to 350°F. Line a baking sheet with parchment.

2. Rinse seeds and pat very dry. Allow to air dry for 15 minutes to ensure dryness.

3. Toss dry seeds with a little oil or nonstick spray. Sprinkle on any desired spices.

4. Spread seasoned seeds in a single layer on the parchment.

5. Roast for 15-20 minutes, stirring halfway. Seeds are done when shells are crunchy and lightly browned.

6. Let cool and enjoy. Store leftovers in an airtight container for 1-2 weeks.

Almost any spice blend complements roasted watermelon seeds. Try sea salt, chili powder, onion powder, garlic powder, cinnamon or curry spices.

Roasting at a low 300°F for 30-40 minutes also works if you prefer very crisp shells. Keep an eye on them so they don’t burn.

Are Watermelon Seeds a Nutritious Snack?

Watermelon seeds are highly nutritious in their own right and make a great healthy snack anytime. A 1-ounce serving of dried watermelon seeds contains:

– 158 calories
– 14g fat
– 6g protein
– Magnesium, potassium, phosphorus, manganese, copper
– Iron, zinc, calcium
– Vitamin B6, niacin, folate
– Healthy unsaturated fats and fiber

The protein, healthy fats and variety of vitamins and minerals make watermelon seeds a very nutrient-dense choice. The high fiber and fat provides satiety as well.

You can roast them plain, or flavor with spices like:

– Sea salt & black pepper
– Chili powder & lime juice
– Cinnamon & ginger
– Garlic salt & onion powder
– Curry powder & cayenne

Watermelon seeds are portable, non-perishable and easy to keep on hand for a highly nutritious snack any time of day. One serving provides a substantial amount of nutrition in a compact package.

What Are Some Common Ways to Eat Watermelon Seeds?

Beyond snacking on dry roasted seeds, there are many ways to enjoy the nutrients and texture of watermelon seeds:

– Add to granola, trail mixes and snack mixes
– Toast and grind into nutritious watermelon seed butter
– Mix into baked goods like bread, cookies and muffins
– Use in place of nuts in pesto, sauces and condiments
– Sprout seeds for use in salads, sandwiches and smoothies
– Candy roasted seeds with honey, sugar or maple syrup
– Infuse into water for nutty electrolyte water
– Turn into milk for use in smoothies, lattes and recipes

Watermelon seeds are a versatile ingredient. Their mild flavor allows them to be easily incorporated into both sweet and savory foods. Consider using watermelon seeds in any recipe that calls for pumpkin, sunflower or flax seeds too.

With some creativity, this nutritional powerhouse can be transformed into a wide variety of tasty dishes and drinks. Keep a batch on hand to boost meals, snacks and beverages with extra nutrition and crunch.


While an urban myth says black watermelon seeds are toxic, this is not true – watermelon seeds of any color are perfectly edible. White seeds may contain slightly higher levels of fats, protein and minerals, but both seed types provide nutrition.

Despite their hard outer shell, watermelon seeds are digestible when chewed properly. The human digestive system breaks down the cell walls, releasing the nutrients inside. Swallowed seeds will not sprout or grow into watermelons in your stomach.

Watermelon seeds are safe to consume either raw or roasted. Roasting brings out more flavor at the cost of losing some nutrients. But soaking, boiling and sprouting make raw seeds softer and easier to chew as well.

The many nutrients and minerals, high protein and fiber, and versatility of watermelon seeds make them a nutritious addition to snacks, meals and recipes. While the myths around black watermelon seeds being toxic persist, science confirms both black and white seeds are good for you.

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