Laidback Gardener Tip of the Day

Gardening Myth: De-leafing Tomato Plants

20150821AAt the end of the summer, my father always stripped the upper leaves off his tomato plants so the fruits would mature more quickly. After all, he reasoned, exposing the leaves to the sun makes them ripen, so getting rid of the leaves shading his tomatoes ought to ensure an earlier harvest.

And he wasn’t alone in this belief: it was common practice 50 years ago and is still done by many gardeners to this day. But they’re wasting their time.

Tomatoes ripen when they are ready to mature, period. You can’t do much about it. The weather is a factor, of course: they do ripen most quickly at warm but not hot temperatures, but what can you do about that?

The Two Tomato Test

It’s easy enough to prove that exposure to sunlight doesn’t help tomatoes mature. Just harvest two tomatoes that have started to turn red but aren’t quite ripe. Place one in a brown paper bag, perhaps putting it in the pantry, and leave the other exposed, setting it on a sunny windowsill. You’ll see that both mature at the same time and yet the one kept in the paper bag received absolutely no sunlight.

Sun-scald and Insipid Taste

The worst part of this myth is that not only stripping tomato plants of their leaves doesn’t help the fruit mature, it can be downright harmful.

20150821B
Sun-scald on a ripening tomato

Fruits that were completely shaded by leaves, then suddenly exposed to full sun, may actually suffer sun-scald (the plant equivalent of sunburn) and, although they are still edible, won’t be as presentable.

Also, it is foliage, because it captures the sun’s energy and converts it into sugar, that gives tomatoes their sweet taste: if you strip the plant’s leaves, your tomatoes won’t be quite as tasty!

Of course, you can remove yellow, brown or diseased leaves (that’s another story entirely), but leave green leaves intact if you want the tastiest, prettiest tomatoes in town!

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

2 comments on “Gardening Myth: De-leafing Tomato Plants

  1. Pingback: Tomatoes Too Can Get Sunburn – Laidback Gardener

  2. Removing leaves and giving full sun “to ripen” is utter nonsense.
    Removing the lower (first) leaves when they yellow is a good idea for providing ventilation, in turn helping prevent basic blights, etc.. But that’s all.

    “Full sun” will normally toughen skin — and has little to do with the ripening process.

    Most importantly… The tomato plant (all tomato plants) need leaves to produce sugars within the fruit!
    So if you can’t resist removing leaves, only remove about a third of the total number of leaves on the plant. This will at least give your fruit a fighting chance of reaching maximum flavor.

    I don’t know when or why, but someone thought removing leaves was a good idea and it seems to be influencing far too many growers. This year especially I see countless bare stalks with tomatoes on them. Ridiculous and against the science of the ripening of tomatoes.

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