Getting the Best Tomato Harvest – Vigilance Required

It’s been a great tomato year so far, especially after 2009.  We are well into tomato roasting, tomato drying, catsup-making and BLT’s. But it’s never too late for nature to pipe up and say don’t count your chickens.

Two cases in point: Hurricanes and Hornworms.

tomatoes, mixed varieties

Most of these tomatoes would still be on the vine if heavy rains weren’t on the radar. The very green ones are almost ready, btw. They will still be green when ripe, just slightly yellower


If you’ve had plenty of rainfall or have been irrigating your tomatoes, this does not apply to you, but if things have been dry lately and heavy rains are on the way it’s likely that you have many tomatoes that aren’t ripe enough to pick yet but are too ripe not to pick – because they’re going to crack, every last one, if they’re still on the vine when the roots get a thorough soaking.

Tomatoes that are fully mature and well-imbued with strong color will ripen off the vine because tomatoes are climateric fruits, like bananas, peaches, avocadoes and pears. They can continue to improve after picking as long as they were full grown when they left the plant. Non-climateric fruits like strawberries, melons and cherries do not have this property. With non-climaterics, what you pick is what you get no matter how long you wait.*

almost-ripe vs ripe tomatoes

Left to right: Pruden’s Purple, Sweet Chelsea, Cosmonaut Volkov. On top, too ripe to leave on the vine if danger threatens; on the bottom, the color they should (and will) be for best flavor and texture.

For tips about ripening tomatoes indoors, consult There’s More Than One Way to Ripen A Tomato, over at Margaret Roach’s A Way To Garden. I agree with most of it.


Tomato hornworm, Manduca quinquemaculata

Tomato hornworm, Manduca quinquemaculata. Spawn of the devil (spawn of the 5-spotted hawkmoth, actually)

Or maybe spawn of the (too-closely) related Tobacco hornworm, Manduca sexta.

Quinquemaculata has v-shaped white markings and a red horn; sexta has white diagonal stripes and a black horn. This distinction matters to somebody.

To tomato growers, not so much. Both of them are big and green and well equipped with teeth.

hornworm with finger

My index finger isn't that big for a finger. A very hungry caterpillar the size of my finger, however...

hornworm mouth

Hornworm front end. Get a load of them choppers.

They eat tomato leaves and fruits and stems, also peppers and potatoes and, less commonly, eggplants. Also wild solanaceae like Deadly Nightshade which is alas not deadly to them.

And they are very cleverly camouflaged, you almost always see the damage before you see them. Then you look and look for them… in vain; you still don’t see them.

Even after they’re enormous they somehow manage to hide, so you find yourself staring at a wounded plant and reflecting that the attacking organism is about the size of a Volkswagon and you still can’t see it.

Keep trying. Hand picking is the best organic control – the only organic control after they get big and semi-immune to Bt – and once they start bulking up they can completely defoliate a good sized plant in just a few days.

pepper plant with hornworm damage

Pepper plant with hornworm damage; every one of those cut-off stems had leaves and flowers and baby fruit

Finding hornworms. It does get easier as they get bigger, for obvious reasons, but in the meantime:

1. Search at dawn and/or dusk; they don’t like sunlight and hide deep in the foliage in the heat of the day.

2. Look for the droppings, dark green to black, about the size of bb’s. Then look up.

3.  I’ve heard that some gardeners go out at night with black lights. On top of everything else, they glow when thus illuminated.

*Tomato ripening note: At a farmers’ market the other day I heard a vendor explaining that he always waited to pick the tomatoes until they were fully vine ripe because they didn’t ripen off the vine as we well know from supermarket tomatoes blah blah etc.

I don’t know if he knew he was lying – and certainly didn’t ask! – but it’s been bothering me ever since. Oversimplification in the service of great local vegetables isn’t all that high on the list of vices but it does give ammo to the people who want to equate sustainability with ignorant romanticism.

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  • Thank you for the useful information and photographs! I am always uncertain at what point to pick tomatoes (though I did know they will continue to ripen off the vine) and tend to pick them too late. Fortunately we have a cook in the household who can whip up some tomato chutney for canning or soup for the freezer and is generally willing to do so!

  • What all do you do with your dried tomatoes, Leslie? I started drying some, then realized it seems to limit what I can do w/ them subsequently, even though it saves on storage space. F’rinstance, I thought I could reconstitute them to make tomato sauce, but I haven’t been able to find a recipe.

    Also, is it safe to store dried tomatoes in oil, e.g., olive? I read somewhere that storing them in oil could cause bacteria to grow in the jar. Sorry to pester you with questions.

    It was great meeting you at Ken’s opening!

    Ditto on the meeting, and I love questions, so please don’t think you’re pestering.
    Using dried tomatoes is definitely post-worthy, so stay tuned. Meanwhile: we use them to thicken tomato sauce (canned tomatoes + dried tomatoes = thick enough to stick to pasta); in soups and stews – esp. things like Mediterranean fish soup/stew that’s not otherwise heavy on tomato – and in place of raisins/currants with sauteed bitter greens. If you have plenty, you can also just set out a bowl of ’em with the chips and olives to accompany drinks. Very nice to nibble.

    You read sort of correctly about the oil. Correct part: Don’t Do It!! Even in the fridge, and that also goes for garlic, which is even more hazardous. The oil excludes air, setting up anaerobic conditions that permit the growth of botulism. Incorrect part: the oil doesn’t cause bacterial growth, just allows it to happen if the bacteria are present.

  • Naseer Said,

    Thanks for the advice, Leslie! We actually had an amazing harvest going, with 15-20 tomatoes coming off the vine every day, and then BAM! a few inches of rain in as many days. Pretty much everything cracked. We’ve since taken off all the bad fruit, and there are some small green ones that will replace them in a few weeks for a final harvest, but we’ve definitely learned our lesson. Next year, we will be wary of heavy rains after a dry spell.

    Beautiful pictures! What are the many varieties that I see there?

  • Thanks Leslie–much appreciated! I probably will quote you in my Farm newsletter. But info is useful to me personally as well.

  • Anna Barker Said,

    So THAT’s why my tomatoes have been cracking! I thought it wasn’t enough…lime…or something…

  • Greg Monger Said,

    Leslie, I really enjoyed the article on tomatoes. Here in the desert southwest, we have a unique and difficult environment for growing tomatoes, way too hot in June, and a rainy season in July/August. I waited to plant my seedlings until late June, and still havent harvested any (planted Roma’s), but have a lot of green ones coming along. My question is, I really must irrigate my tomatoes daily or it is way too dry for good growth. Will this cause my tomatoes to crack? Also, can cracked fruit be used to make canned tomatoes/sauce/etc? If not,why not? Thanks for the help.

  • Susan Said,

    Glad I wasn’t the only one with hornworms! And thank you, I didn’t know they were eating the peppers, too. (I blamed the deer.) But….I don’t get them every year. This was the first, in fact, in about 4 years. You too? Any way to predict seasons when they’ll appear?

    Hi Susan

    Condolences on the peppers, being smaller plants they do tend to get bigger damage in a shorter time. As for your questions: Yes, they’re intermittent here too, but no, I don’t know how to predict when they’re going to show up. Given that their parents are hawkmoths, I guess a garden full of same might suggest trouble for the following year, but even if that’s true I don’t know what we could do about it. Try even harder to encourage birds, I guess.

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