The past tense of put one's hand to the plow is also put one's hand to the plow.

The third-person singular simple present indicative form of put one's hand to the plow is puts one's hand to the plow.

The present participle of put one's hand to the plow is putting one's hand to the plow.

The past participle of put one's hand to the plow is put one's hand to the plow.