Tomatoes Are Green Inside: Causes, Fixes, and Safety Tips

Tomatoes are green inside—why does this happen? It’s usually because the ripening process was interrupted either by:

• Early picking
• Cold weather
• The variety of tomatoes.

Don’t worry! I’ll show you why it happens and how to fix it so your tomatoes ripen perfectly inside and out.

Keep reading for easy tips on how to grow the best tomatoes ever!

Key Points

• Tomatoes are green inside when they ripen unevenly due to factors like early harvesting or cold temperatures.
• Picking tomatoes too soon can leave them green inside while the outside turns red.
• Tomatoes need consistent warm temperatures, especially at night, to ripen evenly.
• Certain tomato varieties naturally have green cores, even when ripe.
• Inconsistent watering stresses tomatoes and leads to uneven ripening.
• Sunscald from too much direct sunlight can cause green interiors while the outside ripens.
• Green tomatoes are safe when cooked, as cooking reduces solanine levels.

Tomatoes are Green Inside? Know the 7 Causes

Tomatoes can stay green inside because of several reasons, which are:

• Being picked too early
• Temperature problems
• Nutrient imbalance
• Inconsistent watering
• Sunscald. 

Now, the details.

Immature Harvesting: Not Choosing the Right Time

A common cause of green insides in tomatoes is early harvesting. If you harvest them before time, they will stay green from the inside (even if the skin turns red).

This happens because tomatoes need time to develop and ripen fully. When left on the vine, they go through a process where the green chlorophyll breaks down, and the red pigments take over.

But if the fruit is picked early, that process gets cut short. As a result, the insides stay green and sometimes even hard.

Temperature Issues

Temperature plays a huge role in how tomatoes ripen. Tomatoes need warm weather to ripen evenly. Ideally, temperatures should stay between 70 and 84°F. When it’s too cool, especially at night, tomatoes struggle to ripen properly, which can leave them green inside.

I’ve seen this happen when the weather suddenly turns chilly (even if the days are still warm). The cooler nights slow down the ripening process. Hence, the insides of the tomato don’t catch up to the red outside.

If you live in a place with unpredictable weather, try using row covers to keep your tomatoes warm at night.

I’ve also found that growing tomatoes in containers makes it easier to move them to a warmer spot if the temperature drops.

Just keeping them cozy during cooler nights can make a big difference in how well they ripen.

Variety

Not all tomatoes ripen the same way. Some tomato varieties naturally have a green core or stay green inside even when fully ripe.

I’ve noticed this with heirloom varieties in particular.

So, sometimes, the green color inside isn’t a sign of under-ripeness. It can be just part of the tomato’s natural characteristics.

If you often find green cores in your tomatoes, you might want to look into the variety you’re growing. Some tomatoes, like “Green Zebra,” are meant to be green inside!

If you prefer fully red tomatoes without any green parts inside, consider switching to a hybrid variety that ripens more evenly.

Nutrient Imbalance

I’ve learned that too much of certain nutrients can mess with tomato ripening. For instance, if there’s too much nitrogen in the soil, your tomato plant will focus more on growing leaves and stems rather than ripening its fruit.

Nitrogen is great for green growth, but too much of it can leave the fruit green inside.

Tomatoes need a balanced diet. Phosphorus and potassium are super important for helping the fruit ripen properly.

Inconsistent Watering

Watering your tomatoes unevenly can also cause them to ripen unevenly. Scientia Horticulturae Volume 316 states that both overwatering and underwatering can harm plants.

I’ve had trouble in the past with forgetting to water my plants consistently. Unfortunately, it showed in my tomatoes.

When tomatoes don’t get enough water, or if they get too much water all at once, they can become stressed. This stress can lead to green insides.

Hardened Green Core

A hardened green core is a condition where the center of the tomato stays green and tough. I’ve seen this happen when tomatoes go through a lot of stress. Things like these can lead to this issue:

• Big temperature swings
• Too much nitrogen

When the core stays green and hard, it usually means something interrupted the ripening process.

Sunscald

Sunscald happens when tomatoes get too much direct sunlight. The outer part of the tomato ripens quickly because it’s getting blasted by the sun. But the inside can’t keep up, leaving it green.

Green inside is one problem, but rotting tomatoes is another. Here are 6 causes and 8 fixes for tomatoes rotting before they’re ripe.

How Can I Fix Green Tomatoes on the Inside? 6 Solutions

To fix green tomatoes on the inside, do the following:

• Leave them on the vine until fully ripe
• Provide warmth to maintain ideal temperatures
• Water consistently
• Balance fertilization
• Shade the plants (if sunscald is an issue).

Let’s look at how you can fix these problems step by step.

Allow Full Ripening

One of the easiest ways to fix green tomatoes on the inside is to just wait a little longer. I’ve learned that tomatoes need time on the vine to ripen fully.

Sometimes, they can look red on the outside before they’re fully ripe inside.

If you can, leave the tomatoes on the vine until they feel soft when gently squeezed. That’s usually a good sign that they’re ready.

If you need to pick them up early for any reason, you can still let them ripen indoors. Just place the tomatoes in a warm spot, or try the paper bag trick with a banana. The banana gives off ethylene gas, which speeds up the ripening process.

Maintain Ideal Temperatures

To achieve even ripening, it’s important to maintain the right temperature for your tomatoes. In my garden, I’ve had success using row covers to keep the tomatoes warm at night.

If you’re growing tomatoes in containers, you can move them to a warmer spot when temperatures drop.

Choose the Right Variety

If you consistently get tomatoes with green insides, you might want to think about the variety you’re growing. Some tomatoes naturally have green cores or ripen unevenly. Heirloom varieties are known for this.

While they’re delicious and unique, they can sometimes be tricky when it comes to even ripening.

Switching to a hybrid variety that’s bred for uniform ripening can solve this problem. I’ve found that these varieties are more reliable.

If you love heirlooms but want to avoid green cores, try picking ones that are known for even ripening. Examples are “Cherokee Purple” or “Brandywine.”

Balance Fertilization

Fertilization is key to getting tomatoes to ripen evenly. According to research, using too much nitrogen in your fertilizer can force the plants to focus on leaf and stem growth instead of ripening the fruit.

This can leave you with big, healthy-looking plants but green tomatoes on the inside.

To fix this, try switching to a balanced fertilizer that’s low in nitrogen but higher in phosphorus and potassium. These nutrients help promote fruit development and ripening.

Look for fertilizers with a ratio of 5-10-10 (where the second two numbers are higher).

In my garden, I also use compost to naturally enrich the soil. It has helped my tomatoes ripen more evenly.

By giving your plants the right nutrients at the right time, you can help them produce tomatoes that ripen evenly both inside and out.

Water Regularly

Watering tomatoes regularly is another important way to fix green insides. According to an MDPI article, incorrect watering can cause different plant problems, including root rot. This ultimately harms the fruit production.

Therefore, water your tomatoes deeply and consistently. I usually water mine once or twice a week, depending on the weather.

Provide Shade

Sunscald can cause the outside of tomatoes to ripen faster than the inside. I’ve noticed this when my plants are exposed to direct sun rays. The fruit develops a tough, leathery skin while the inside stays green and under-ripened.

To fix this, try providing some shade for your tomato plants. You can use a light cloth or shade net to protect them from harsh sunlight, especially during peak hours.

I’ve also planted taller plants, like corn or sunflowers, nearby to give my tomatoes some natural shade. This keeps them from getting too much sun and allows them to ripen more evenly.

Giving your tomatoes some protection from the intense sun can help ensure that the inside ripens at the same pace as the outside, preventing green or hard cores. Plus, it can help prevent other issues like cracking or sunburn.

Want more tips? Here’s how to keep plants from burning with easy garden care methods.

Are Green Tomatoes Safe to Eat? (Everything to Know)

Green tomatoes are safe to eat, but unripe ones contain solanine, which can be mildly toxic in large amounts. Cooking green tomatoes reduces the solanine content.

They’re often used in recipes like fried green tomatoes or pickles, which are delicious ways to enjoy them.

Understanding Solanine in Green Tomatoes

Green tomatoes, especially unripe ones, contain solanine. It’s a natural compound that becomes harmful in large quantities. However, you’d need to eat a lot of raw green tomatoes for it to cause any real problems.

In my experience, I’ve eaten plenty of green tomatoes without ever feeling sick, but I always cook them just to be safe. Cooking helps break down solanine, making green tomatoes perfectly safe to eat.

According to researchers, Solanine is more concentrated in the leaves of the tomato plant. So, as long as you stick to eating the fruit, you’re unlikely to have any issues. Green tomatoes can have a slightly tart flavor, which makes them great for pickling or frying.

I’ve made fried green tomatoes before, and they turned out delicious! So, if you find yourself with green tomatoes, don’t throw them out—cook them up and enjoy.

Cooking Green Tomatoes

Cooking is one of the best ways to enjoy green tomatoes safely. I’ve found that cooking green tomatoes not only reduces the solanine but also brings out their unique tart flavor. Frying green tomatoes is a classic dish that’s easy to make.

Just do this:

• Slice the tomatoes.
• Then, dip them in some flour, egg, and breadcrumbs.
• After this, fry them until golden brown. They will be crispy on the outside and slightly tangy on the inside—a great way to use up green tomatoes.

Pickling is another option. You can slice the green tomatoes and pickle them in vinegar, sugar, and spices to create a tangy snack.

I’ve also used green tomatoes in stews or chutneys, where their firm texture holds up well during cooking.

When Not to Eat Green Tomatoes?

Although green tomatoes are generally safe to eat when cooked, there are times when you might want to avoid them. If the tomatoes are very small and haven’t started ripening at all, they may have higher levels of solanine.

I usually wait until my tomatoes are at least starting to turn red before I cook with them.

Also, if you have any concerns about solanine or are feeding young children, it’s always a good idea to cook the tomatoes thoroughly to be on the safe side.

Tomatoes being green inside might be one problem, but pest attacks can add to it. Here’s what to do if your tomatoes have been damaged by caterpillars.

Conclusion

To sum up:

• Tomatoes stay green inside when you harvest them early or don’t water them properly.
• Watch the temperatures, especially at night, to help tomatoes ripen evenly.
• Choose tomato varieties known for uniform ripening.
• Use balanced fertilizer to avoid too much nitrogen, which can delay ripening.
• Water tomatoes consistently to prevent stress and uneven ripening.

With these tips, you’ll enjoy ripe, juicy tomatoes both inside and out.

Just like tomatoes can have internal problems, cucumber plants can show yellow leaves—find out the causes and how to fix it to keep your garden healthy.