Here is an interesting observation from another site I contacted. Their thoughts that the pine needle mulch is the problem is contrary to what many people told me, as they said that tomatoes like acid soil. Here is what he said, any thoughts? Pete Hello - Thanks for e-mailing us. Our greenhouse growers looked at your e-mail and said the only thing that would hurt your tomatoes growth was the pine needle mulch. Pine needles add acid to the soil. Very few plants will grow under a pine tree and thrive. Hope to e-mail you again soon.