Is This Tomato Ready to Harvest?

Open a seed catalog and you will see a vast array of tomatoes. Gardeners can choose from plants bred for container growing or planted directly into an inground bed (raised or otherwise). Some tomato plants require trellising while others can grow without staking or support. When it comes to color, shape, size, days to harvest, disease resistance and flavor, the options seem endless.  In fact, according to Vegetables: Growing Tomatoes in Home Gardens published by Washington State University Extension, there are over 7,500 varieties of tomatoes.

The tomato, Solanum lycopersicum, may be the most loved edible in a home gardener’s vegetable patch.  Regardless of whether you grow your own tomatoes, purchase them from a local farm stand or market, or a friend gives them to you, we all look forward to that first bite of perfectly ripe tomato.  Good things follow that first delicious bite: BLTs, salads adorned with halved yellow and red pear tomatoes, sliced yellow, red, purple or orange tomatoes coupled with fresh mozzarella and basil. Ask a gardener for his or her favorite way to enjoy a tomato and the range of answers will be as varied as the gardeners themselves.

At first blush, tomatoes may seem easy enough to grow. Some gardeners start their own tomato seeds because selecting from that vast array of options is too good to pass up. Others prefer to purchase seedlings ready to transplant into a container or garden bed. Generally, once the plant is in the ground, the countdown to harvest begins. While tomatoes are relatively easy to grow, there may be a few challenges along the way and that makes the end prize more compelling.

Regardless of the type of tomato, there is a series of stages tomatoes go through before arriving at that perfectly ripe first bite. Those stages are an important key to understand when asking, “Is this tomato ready to harvest?"  When thinking about those stages, consider the roles of lycopene and ethylene, respectively, in the maturation process of a tomato.

As a reminder, lycopene is a carotenoid that provides the red coloration to many fruits and vegetables and ethylene is a gas naturally produced by maturing tomatoes. In some cases, tomatoes are harvested green, loaded into a chamber where they are flooded with ethylene. The resulting tomato may not be as colorful nor as tasty as a tomato allowed to stay on the vine longer for the natural ripening process to proceed.

Six stages of tomato ripening are more fully described in the April 10, 2020 Organic Farming and Gardening School article entitled Six Ripening State of Tomatoes by the Fruit Surface Color by John Michael.

Six Ripening Stages of Tomatoes

1. Green Mature Stage

At this point in the fruit’s development, color will be visible inside the fruit but not yet visible on the outer skin. If the fruit is picked at this point of development, the flavor will not be fully developed.

2. Breaker Stage

In the Breaker Stage, color will be visible at the blossom-end of the tomato skin and tomatoes are considered to be “vine ripe." The color change at the blossom end indicates the tomato is producing ethylene, a ripening agent produced by the plant.

It is also at the Breaker Stage that the tomato receives no additional nutrients from the plant. In fact, a skin will form between the plant stem and the plant, effectively cutting off nutrients from the plant to the fruit.

According to the above-referenced article, benefits of allowing the Breaker Stage tomatoes to ripen off the vine include:

• The tomato has a vine-ripened flavor (note here that sunlight is not a factor in fruit ripening).
• The tomato is not susceptible to cracking, due to excess moisture flowing into the fruit.
• Sunscald is not an issue.
• Additional insect damage is avoided.

3. Turning Stage

In this stage. between 10% and 30% of the tomato's skin is pink, pinkish or red.

4. Pink Stage

In this stage, the coloration has spread to 30% but not exceeded 60% of the tomato skin. The fruit is also becoming a bit softer to the touch.

5. Light Red Stage

In the Light Red Stage, the coloration has spread to 60% but has not exceeded 90% of the tomato skin.

6. Red and Final Stage

Finally, at this point, 90% of the tomato has that classic red color and is ready to eat from the vine.

The question of whether or not a tomato is ready for harvest, continues to be a debate among many gardeners. From a strictly physiological perspective, tomatoes are ripe at the breaker stage; however, those tomatoes will not be sporting the classic red (or yellow, or orange) color. In addition, conventional wisdom is that a tomato is vine-ripened when it's reached its full color. 

It is important to remember that tomatoes continue to ripen even after they are picked.  In fact, if weather stays very hot, above 85°F, then ripening slows or stops. To avoid storm damage and sunscald, it may behoove the gardener to actually ripen the fruit off the plant. See Why Aren't My Tomatoes Ripening?

This question of when to harvest tomatoes provides a perfect opportunity to run a tomato trial in your own garden. You can try harvesting your tomatoes and different stages and conduct a taste test.  Start planning now for next year. A few preliminary steps include:

• Select a portion of an existing garden for the trial or set aside a new space.
• This fall, test the soil and amend as indicated in the soil test (remember, more fertilizer is not necessarily better).
• Make a tentative list of the type(s) of tomatoes you are interested in enrolling in your trial.
• Review your current list of seed catalogs; consider adding a few different catalogs.
• Ask a gardener friend to run the same trial in their garden and compare notes through the trial and at the end of the season.
• Share your results with friends, other gardeners, and the Penn State Extension Master Gardener Program!

References

Oregon State University Extension, Master Gardeners.  Growing Tomatoes in the Home Garden

Washington State University Extension. Vegetables: Growing Tomatoes in Home Gardens

University of Tennessee Extension. Backyard Series:  The Tennessee Vegetable Garden - Growing Tomatoes

Cornell Cooperative Extension, Cornell Vegetable Program.  Why Aren't My Tomatoes Ripening?

Oregon State University Extension  Grow Your Own Tomatoes and Tomatillos

Kansas State University, Research and Extension - Johnson County  Harvesting and Ripening Tomatoes

Purdue University Extension, Indiana Yard and Garden - Consumer Horticulture.  Tomatoes not Ripening?

University of Georgia Cooperative Extension  Tomatoes can be picked at breaker stage or later

OFAGS (Organic Farming and Gardening School)  Six Ripening Stages of Tomatoes by the Fruit Surface Color