my tomatoes are nicely shaped but the stem ends have woody pieces going into the tomato. How can this be prevented?
Muskegon County Michigan tomatoes
It appears from your description that you may be referring to what is called white core of tomatoes. This is believed to be linked to yellow shoulder disorder. This disorder is rather complex and is related to proper nutrient availability at fruit set. Other factors include temperature, soil and water pH and variety of tomato. Take a look at the following links for more information:
I hope this is helpful,