This is why some garden tomatoes cracked this summer

"Fielding Questions" columnist Don Kinzler also answers questions about transplanting grass and how to best store garden chemicals.

A reader wonders why their Better Boy tomatoes cracked this year. Special to The Forum
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Q: The photo shows how my Better Boy tomatoes look this year with all the cracks. My other tomatoes look fine. Any idea what could be causing this? — Susie A.

A: When tomato fruits develop rings that circle around the exterior, as shown in your photo, the disorder is called concentric cracking. It’s not a fungal or bacteria disease, nor any malady for which we can spray or apply any preventative products.

Concentric cracks are caused when the interior of the tomato grows more quickly than the outside. The fast internal growth spurt causes the outer skin to split, causing blemished cracks. The most common cause of the growth spurt and resulting cracks is rain following dry weather.

Tomato cultivars vary greatly in their susceptibility to cracking. Types that are less prone to crack include Mountain Spring, Mountain Fresh, Big Beef, Celebrity, Jetstar, Park’s Whopper Improved and Super Fantastic. Although some sources list your Better Boy as having crack resistance, it doesn’t appear to be as crack-free as the others listed.

Cracking can be mitigated somewhat by striving to keep moisture uniform around tomato plants by eliminating swings between dry and wet soil. Mulch helps greatly.


A reader wonders why their Better Boy tomatoes cracked this year. Special to The Forum

Q: Can I still thin out ornamental grasses, or is it too late now in October? — Debbie E.

A: Ornamental grasses are best divided and transplanted in spring, just as new green spears are first noticeable. Fall can be a little riskier, but we can be successful doing things outside of the best recommended time if we’re aware of the increased chance of something going wrong, like winterkill.

Whether or not to divide and disrupt ornamental grasses in fall instead of spring depends on the amount of risk you're willing to take, or how valuable the plants are. If the upcoming winter has moderate temperatures and a layer of insulating snow, all will be well. If the temperatures are extremely cold with no insulating snow, freezeout is more likely.


Q: I’ve got a variety of garden chemicals left from this summer, including fertilizers, weed killers and insect sprays. Can I keep them in the garage, or is there a better place? How long do these products last? — Bill W.

A: Most garden chemicals, including fertilizers, herbicides and insecticides, have a shelf life of at least two to three years if stored properly. Store in an area that’s cool, but won’t freeze, which can quickly ruin liquid chemicals. Insecticides and herbicides are also best stored away from living areas, both for safety and because some have objectionable odors.


Herbicides have been known to cross-contaminate products stored close to them, such as fertilizers that could potentially absorb the herbicide’s fumes. Store granular fertilizers in tightly closed plastic bags, which will also keep the product dry.

If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.

Don Kinzler column mug.jpg
Don Kinzler, "Growing Together" and "Fielding Questions" columnist.

Don Kinzler column mug.jpg
Don Kinzler, "Growing Together" and "Fielding Questions" columnist.

Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at
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