Radish seeds hanging in a factory seed tube angled at only 30 degrees from vertical.

Needham Ag Technologies has developed a smooth internal rubber seed tube for box drills. 

According to the company, driving up or down slopes can bunch up the seed tubes and cause the seeds — particularly lighter ones like radish or grass seeds — to hang in the corrugations of the tubes. When the seed tube straightens back out or there's enough vibration to shake the seeds loose, the seeds will often fall out in clumps, resulting in inconsistent seed placement down the rows. 

To remedy this problem, Needham Ag Technologies has sourced a new design of rubber seed tube to help improve seed flow, especially when seeding smaller seeds. Made from natural rubber, they're flexible and incorporate internal folds above each corrugation, so as the seed tube stretches out, the folds direct the seeds away from the corrugations to help keep the seeds from catching. 

The seed tubes also incorporate a small amount of peroxide into their formulation, which has been found to be a safe and effective way of deterring rodents from damaging the tubes.

The tubes come in three sizes and fit most drills available on the market. Visit Needham Ag Technologies' website for more information.