Attack of the killer tomato problems!

It always seems that as soon as the tomatoes start to ripen, the tomato problems start. After all this anticipation, it’s a real disappointment to have a gorgeous green tomato ripen for weeks and then … ugh. Nasty tomato hornworms strike! The bottoms of the tomatoes are all brown and icky! And why is this tomato so droopy/purplish/yellowish/sad-looking?

This is by no means a comprehensive list of the possible problems you could be having with your beloved tomatoes, but they are the most common issues I’ve noticed in my own garden, in questions from gardeners and in some of the samples brought in when I volunteer at the Colorado State University Cooperative Extension desk.


Inevitably, I end up with at least a few of these problem tomatoes every year. The telltale sign of blossom-end rot is a brownish spot on the bottom of the fruit. It looks a little mushy but it’s actually kind of leathery, and eventually can turn black.

At first, I tried letting the tomatoes with this problem ripen, thinking I would just trim off the brown end. Bad idea. It took forever for the tomatoes to mature and they tasted terrible. I mean, worse than grocery store tomatoes in January. Yuck.

Blossom-end rot is technically a sign of calcium deficiency. However, the sprays/calcium supplements marketed for this problem aren’t effective, in my opinion. You’re far better off changing the way you water your plants. What I’ve noticed is that when the weather changes or I get lazy about watering, that’s when blossom-end rot strikes. I’m a habitual over-waterer this time of year. We had a hot spell, I went nuts with the watering, and now it’s cooling off and we might get some rain. It’s time to back away from the water, or I start causing problems like this.

Blossom-end rot can also occur if you damaged the plant’s roots or if you over-fertilized. My best advice is, if you have it, remove the affected tomatoes, re-evaluate your watering and fertilization. Chances are you are overdoing it.



Growth cracks are exactly what they sound like — think of them like stretch marks for tomatoes. They’re ugly, but they’re just a sign that the fruits developed rapidly and couldn’t keep up with themselves. I usually get them running downward from the stem, but they can also happen in a circular pattern around the tomato. Once again, it’s time to reconsider the watering schedule. Mulching your plants might help, since it will help keep the soil moisture level more constant and you won’t have to water as often. Just be careful to cut back on the water if you mulch, or you’ll really drown the plants.



These guys are in full force now. They look like characters from a sci-fi movie — bright green, up to four inches long, with a spiky horn coming out of their back ends. Yeah, they’re creepy. They’re the biggest caterpillar you’ll find in gardens around here and seeing one munching the tops of your tomatoes is a little freaky.

But have no fear, they’re actually easy to deal with — you just have to pick them off. Yep. Just get out those long-arm barbecue tongs and go to town. Actually, I do it by hand but I realize there’s a certain ick factor here, so maybe bribe your neighborhood kids to collect them and put a bounty on each caterpillar’s head. You can use insecticides like spinosad or permethrin (among many others) to kill them, but if I see one of these buggers devouring my tomato plants, I want it off right away, so I bite the bullet.



The Fourth Annual Lavender Festival is happening today and tomorrow in Palisade. Check out the free demos in Palisade Memorial Park, tour an assortment of lavender farms, or attend an educational seminar for a small fee. Sessions include information on growing different types of lavender, research results on what grows best here, and inside tips from local lavender growers. Visit for more information.

Erin McIntyre is an advanced master gardener, writer and Grand Valley native. Please email her at .(JavaScript must be enabled to view this email address) with story ideas or feedback.


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