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Can I Eat Tomatoes Sprayed with Bonide Rot Stop?

August 02, 2008

J. Laframboise (what a great name!) writes in from Rhode Island to ask:

“We have tomato blossom end rot and I would like to know if it is safe to eat the tomatoes not affected even though they’ve been sprayed with Bonide rot stop”

(Update July 2015: If you’re really just seeking to identify and remedy what’s causing your food crops to rot, read our latest article on a couple of these common issues here.)

I’ll start by saying that this isn’t a problem I end up dealing with very often. Ironically, I tend to find it is a problem here in Seattle when we get a lot of late season rain (after our seasonal summer drought) before the fruiting is finished or when I water at night or when I neglect watering and the plants dry out and then get a heavy dose of water. Basically, it seems to happen when the plants are stressed unnecessarily.  I mulch regularly and have built some great soil that my plants seem to love. If anything I’m low in Nitrogen, which if used heavily on tomatoes, can lead to rot issues.

I’ve done some additional reading on this problem, and found that the problem comes from a calcium deficiency. (Another reader wrote in on this & I accidentally deleted his post. I hope he writes in again, so I can share his knowledge with you.) Now, keep in mind that calcium deficiency can be the result of planting in soils where calcium is lacking or where it is difficult for the plants to take up.  As well, applying calcium, perhaps as bone meal, to the tomatoes can also help them with this problem.

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Additionally, reducing your cultivation around the roots of your tomatoes is also a good idea. The feeder roots are tender and easily damaged.

Now, I know that’s a lot of information that doesn’t really answer the question about the safety of plants that have already been sprayed with Bonide Rot Stop, but I feel obligated to discuss the problem and optional solutions for the future. But, here are some thoughts on the existing problem.

I don’t use this product myself, so I went to the Bonide Corporation Website to read up on their “Rot Stop Tomato Blossom End Rot” product. It is a product that is designed to be applied to the fruit, so it sounds like you’re good there. It is a product designed to manage the problem that you have, and it does help correct Calcium deficiencies.

I read the label  and discovered that it is 9.2% Calcium from Calcium chloride. It doesn’t tell me how they create the calcium chloride, so I don’t know how sustainable it is to produce. Since this product is a spray, it makes sense that they would use this form of calcium, which is highly soluable.  I tried to do some reading on the MSDS, but the website link is broken.

So, is it safe to eat the fruit? Well, Bonide sells this product throughout the U.S. No states have banned it. What we know of the product seems relatively safe. We don’t know what the “inert ingredients” are, so no ideas on that.

So, can you eat the tomatoes that have been sprayed? Seems okay. Now, I can’t promise that some study someday won’t prove otherwise, but if you trust the chemical company who makes the product you used and you trust the regulatory companies that determine safety, then you should be good to go.

If you’re concerned you did the wrong thing this time, maybe try applying some other calcium sources next time. I like to use egg shells in the garden around seedlings to keep slugs out. The added benefit is that they add calcium to the soil. Oyster and other shell products will do the same; they release slowly though, so keep that in mind.  And, as I mentioned earlier, bone meal is another great way to go.

Thanks for writing in & good luck (and good eating). For more on growing tomatoes, look here.

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