Should your tomatoes be red by now, but they are stuck on green? In this podcast, Joe Lamp’l demystifies the reasons why tomatoes take their sweet time to ripen.
BHG020-Why Won’t my Tomatoes Ripen?!?
This is about the time each year (mid to late summer) that I start getting the same question from a lot of frustrated gardeners; why won’t my tomatoes ripen? They’re big and green on the vine, but they just sit there! Why won’t they turn red?”
Well, first of all, take comfort in knowing that nothing’s wrong. Here’s the dirt on what’s happening; under ‘normal’ conditions, from the point of fertilization, it takes about 50 days until a tomato fruit reaches full maturity. But if you stop to think about it, tomato plants have a lot going on– all at the same time. While they’re producing and ripening fruit, the plants are still putting on new growth, developing more extensive root systems and making components for color and flavor.
Fortunately, tomato plants are equipped to handle this multi-tasking quite well. When conditions are ideal, such as a favorable climate, plenty of spring showers and moderate summer temperatures, plants thrive and the harvest comes quickly. However, those “ideal conditions” are a lot harder to come by these days. Typical spring weather quickly evolves into an overly hot, dry summer. So now, the plants are faced with demands that require some redirection in how their energy is distributed.
The key resource needed to produce the food energy responsible for healthy plants and ripe tomatoes starts with sufficient leaf surface. When plants become laden with fruit, additional foliage surface area is needed to keep up with these increased demands. But now the plant is called upon to spread its energy in a multi-tasking balancing act that becomes even more demanding as the season wears on. So even though tomato fruit reaches full size in about 25 days, it doesn’t completely ripen until sufficient compounds are present to give it the color, taste and texture we love. And with over 400 of these compounds building together into a crescendo of perfection, that won’t happen until conditions are again in balance.
Air temperatures above 85 degrees are one of the most common reasons tomatoes don’t ripen as fast as you might expect. When temperatures rise above this level, tomatoes stop making carotene and lycopene pigments, two of the most important and recognized components in the symphony.
And below ground, temperature is just as important. The roots require soil temperatures below 80 degrees for optimal growth. So as temperatures rise below the soil surface, shallow rooted plants respond by developing a deeper, more robust root system, further diverting the energy needed for ripening fruit.
So if you’ve run out of patience and you just can’t handle Mother Nature’s timetable, there is something you can do to speed up the process. If the plant is laden with fruit, take some off. I know this might be hard to do, but with fewer tomatoes, there’s less demand on the plant and with less demand, there’s more energy that can be concentrated on ripening the remaining ones, when Mother Nature gives the signal to resume.
And here’s one idea you might be tempted to try–adding extra fertilizer seems like a logical thing to do, to give those tomatoes a little extra boost. But don’t do it. The environmental changes that result in this ripening slowdown are nature’s way of dealing with and resolving the challenge. It’s not a nutritional deficiency. In fact, adding fertilizer now could exacerbate the problem by forcing the plants into a growth mode at an inappropriate time.
Tomato plants really are adaptable and they’ll adjust to environmental changes in due time. All that’s required of you is patience, consistent irrigation and a good layer of mulch to help moderate soil temperatures. Just consider it delayed gratification and I promise, you will be rewarded for your patience!
But here’s something you can do that doesn’t require any patience; check out all of our other Burpee Home Gardens Podcasts. There are 26, just like this one, and they’re all designed to help you be a more successful gardener. From planting to harvest, we’re there every step of the way. You can download all the episodes for free in iTunes, or listen online at burpeehomegardens.com where you can also get great gardening ideas and inspiration any time! You can subscribe to the series for free in iTunes, or listen online at Burpeehomegardens.com, where you can also find great ideas and inspiration any time.
Now go get dirty!