When Should I Harvest Or Pick My Heirloom Tomatoes?

Are you waiting until your heirloom tomatoes are fully ripened to pick? From avoiding splitting to critter theft, there are many benefits to picking them earlier. Discover the best stage to harvest heirloom tomatoes and when they’re ready to eat. 

Ripening tomatoes on branch surrounded by leaves.

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Like many gardeners, we once bought into the myth of the vine ripened tomato. When we first started growing tomatoes, we used to leave fruit on the vine and pick at the peak of ripeness.

Through research and experimentation over the years, we’ve learned that picking tomatoes before they are fully ripe (letting them ripen inside) does not adversely affect flavor, and there are actually some major benefits to harvesting them early.

RISKS OF LEAVING TOMATOES ON THE VINE UNTIL RIPE

  • Splitting/cracking: Splitting of tomato skin is caused by a sudden change in moisture. A rapid increase in water levels causes the inside of the tomato to swell faster than the skin can stretch, resulting in cracks. Splitting is common after a hard rain, especially if it has been dry previously. Unfortunately, many varieties of heirloom tomatoes are particularly prone to splitting. Since we can’t control mother nature, harvesting a tomato before it ripens minimizes the risk of splitting due to unforseen changes in moisture levels. If your tomatoes do split, harvest them as soon as possible. Split tomatoes are susceptible to rot and parasites.
  • Sun scald: A telltale sign of sun scald is pale white or yellowish blotches on the side of a tomato where the sun is most intense. If tomatoes are exposed to direct sunlight, they may develop sun scald. Maturing tomatoes are susceptible to this condition, so harvesting early can help to reduce the risk of sun scald.
  • Cold Weather: Autumn nights can get pretty chilly in Colorado (low 50s or below). Cool temperatures are not good for tomatoes. Not only can it cause slow, uneven ripening but it also has a negative impact on fruit quality and flavor. Bringing tomatoes indoors before they are fully ripe ensures that they won’t be exposed to cold or extreme temperature swings during the ripening process. This means even ripening and high quality flavorful tomatoes.
  • Hot Weather: Just as cold can damage tomatoes, extreme hot weather can inhibit ripening.
  • Insect attacks: Insects like the stink bug feed on ripening tomatoes. Harvesting fruit before it ripens minimizes insect damage.
  • Thievery: We have a constant supply of pesky squirrels in our yard. They love taking one bite out of each tomato and discarding them. When the tomatoes turn a vibrant red, the squirrels mistake them for apples (that’s my theory). They’re pretty disappointed after a bite or two. By picking our tomatoes before they fully ripen, we get to them before the squirrels do.

STAGES OF RIPENING

Tomatoes go through several developmental stages on their way to becoming fully ripe. A critical point in this process is the “breaker” stage, the point at which you see the first traces of color, usually toward the blossom end. At this point, the tomato will ripen naturally, even if you remove it from the plant.

The 7 Stages of Tomato Ripening

  1. Immature green
  2. Mature green
  3. Breaker
  4. Turning
  5. Pink
  6. Light Red
  7. Red

The tomato starts out green, but slowly loses the green color from the chlorophyll. As carotenoids and lycopene develop in the fruit, the tomatoes reach their end-stage colors. Most ripening tomatoes will change green hues first, followed by an almost yellow color.

At the breaker stage, the tomato will start to develop streaks of color down at the blossom end. Tomatoes that have reached the breaker stage will finish ripening up off the vine.

The stages of tomato ripening (1-7), from green tomato to red tomato

WILL PICKING TOMATOES BEFORE THEY’RE RIPE NEGATIVELY AFFECT THE FLAVOR?

This long held belief rests on the idea that the vine continues to provide the ripening tomato with nutrients and flavor compounds all the way up until it is fully ripe. On the other hand, we’ve seen claims that upon reaching the breaker stage, the fruit is sealed off from the plant and is no longer supplied with resources that affect flavor or quality.

Jeremy has sifted through the scientific literature to try and settle this debate. This was surprisingly difficult because not many studies have directly addressed this question. In a nutshell, while there is some evidence that the vine can continue to transfer resources to the fruit during ripening, the vast majority of resources are already there at the breaker stage (1,3), and one study (2) shows that transfer stops a few days after the breaker stage.

WHEN TO HARVEST

Given this evidence we usually harvest during the “pink” stage, letting the tomatoes fully ripen indoors after picking. For us, there is no perceptible effect on flavor or fruit quality with this method.

We’ve done side-by-side taste comparisons, and, personally, can’t detect a difference in taste between vine-ripened tomatoes and those harvested at the pink stage and left to ripen inside after picking. Since we detect no differences in flavor, it makes sense to pick early in order to avoid the problems discussed above. Give it a try to see if it works for you.

Heirloom tomatoes on vine at different stages of development and color.

HOW TO PICK AN HEIRLOOM TOMATO FROM THE VINE

DON’T reach with one hand, grab and pull! Picking is a two-handed process. One hand holds the stem just above the fruit. Your other hand gently pulls the fruit from the vine. You may need to twist the tomato slightly as you pull it to ensure it will release easily from the vine.

OR we use garden scissors to snip the vine right above where it meets the fruit.

Both methods reduce the risk of breaking off a large part of the vine when picking a tomato.

HOW TO STORE UNRIPENED TOMATOES

We store the unripened tomatoes in a large, shallow ceramic dish in the kitchen. The dish sits on a table that’s not in direct sunlight. It’s fine to keep them on your kitchen counter as long as the room temperature stays between 65-75°F.

AVOID placing unripened tomatoes in direct sunlight. They do not need light to ripen. High temperatures can inhibit ripening.

DO NOT store them in the refrigerator! Cold temperatures will make them mealy and ruin their flavor.

HOW TO TELL IF A TOMATO IS READY TO EAT

Heirloom tomatoes come in all different shapes, colors and sizes, so a uniformly red tomato is not a surefire way to tell that a garden tomato is ripe. Here are some indicators that we use when deciding whether an heirloom tomato is ready to eat:

  • Check the color on the bottom of the tomato– the darker it is, the riper it is.
  • What variety are your heirlooms? Red varieties should be a deep red when ripe, yellow varieties should be a deep yellow, and so on.
  • Tomatoes ripen from the inside out. A ripe tomato will give slightly to the touch. Be careful not to press too firmly. Use a very light squeeze with your fingers, and the outside of the tomato should give a little.
  • Some varieties, particularly black tomatoes, tend to have green color on the shoulders, even when they are fully ripe. If the rest of the tomato appears to be fully ripe, go ahead and eat it.
Heirloom tomatoes on vine

REFERENCES

  1. Badejo, A.A.Translocation and the alternative D-galacturonate pathway contribute to increasing the ascorbate level in ripening tomato fruits together with the D-mannose/L-galactose pathway. J Exp Bot. 2012 Jan;63(1):229-39.
    https://www.ncbi.nlm.nih.gov/pubmed/21984649
  2. McCollum, J.P. and Skok, J. Radiocarbon studies on the translocation of organic constituents into ripening tomato fruits. Proceedings. American Society for Horticultural Science 1960 Vol.75 pp.611-16.
    https://www.cabdirect.org/cabdirect/abstract/19610300839
  3. Zoltan, P. et al. Color Changes and Antioxidant Content of Vine and Postharvest-ripened Tomato Fruits. HortScience. Volume 45: Issue 3. pp 466–468. Mar. 2010.
    https://journals.ashs.org/hortsci/view/journals/hortsci/45/3/article-p466.xml

top image via depositphotos