Broccolli White 2mm Fibers in Stem - what is that about? - Ask Extension
I'm sorry if I'm out of line asking the extension service to comment on a broccoli defect for a plant I did not grow. But I've been growing broccoli ...
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Broccolli White 2mm Fibers in Stem - what is that about? #924854
Asked February 20, 2026, 10:23 PM EST
I'm sorry if I'm out of line asking the extension service to comment on a broccoli defect for a plant I did not grow. But I've been growing broccoli here in Vt for over 50 years and have never seen the condition that I hope to include in a photo of below. This came from a local super market in the freezer section. I made the super market aware of the product issue and they referred me to the company that provides the product. I sent them several photos including the one below a few weeks ago, and haven't heard back from them. I would estimate that those white tubes in the stem are around 2 mm in diameter, but the cross section is more elliptical than circular.
Again, sorry if I'm out of line here, but I'm really curious about what this could be, and I'm thinking you might be a little less busy in mid February that during the summer.
Lamoille County Vermont
Expert Response
Edward: Thank you for contacting the UVM Extension Master Gardener Helpline. Normally, the helpline does not tend to receive post-harvest questions like this, but we would like to provide you with the following information:
To the best of our knowledge, this tough material you found in your broccoli appears to be overmature pith which is the fibrous material in broccoli stems. Broccoli can become pithy and tough when it is harvested too late or if the plant experiences heat stress during its development. Improper storage may also be a culprit. When broccoli over-matures, its stems can become "woody".
I hope you find this information helpful.
