What's Up With My Mater Plants?

Been growing maters and peppers for the past few years in five gallon buckets, because the soil here is pretty sandy and doesn't grow very well. Had really good luck so far. But this year, the mater plants (Better Boys) look fantastic.....when I go out to water in the morning and again in the evening, they look so healthy I don't turn my back on them for fer of attack. lol But they're SLOW to produce this year. We bought them pretty big.....I'd guess a foot tall about two months ago. Now they are both over five feet tall. One plant has five or six from about 3" in diameter on down. The other has maybe four about 1" in diameter and down. I feel like they're draggin ***. I water them once in the morning and again in the evening and feed them mater and pepper food about every two weeks. We have peppers too and they're kickin butt. What gives with my maters?