Pelleting

Seed pelleting is the process of adding inert materials to seeds  increasing their weight, size and shape. This improves plantability allowing for precise metering, spacing and depth of seed in the field.

If you’re planting a crop that grows from small or irregularly shaped seeds, such as lettuce, carrots and onions, pelleting can help make planting significantly easier on you and your equipment. Pelleting turns a long thin seed into a larger, round-shaped seed, so seeds can be mechanically singulated much more readily and so placed accurately in the field. This helps place seeds precisely, which is a great advantage for crops like onion, which need consistent uniform planting distances between each seed to generate uniform bulb development.

We pellet seeds by applying solid particle fillers to the seed using a binder or adhesive. Seed coating pans are a derivation of confectionary pans. The seed tumbles gently in the pan and like a snowball becomes increasingly heavier, rounder and larger as pelleting material and adhesives are added. The spherical shape allows for precise seed singulation within the planters. Pelleting significantly changes the original size, shape, and weight of a seed. The weight can increase from 1000% to 4000% (a 10:1 to 40:1 ratio).

Seeds of various sizes are commercially pelleted, from relatively large seeds like onion and tomato to very small seeds like lettuce species.

For onion, the seed can increase in weight 6-fold due to pelleting; there are approximately 230 raw seeds per gram, and after pelleting the diameter may be 13.5/64th of an inch (0.54cm). The volume for 1000 propagules is 3.7 cm³ for raw seed compared to 18.0 cm³ after pelleting.

Begonia is the smallest seed that Seed Dynamics pellets. Median seed weight for raw begonia is 88,000 seeds per gram. After pelleting, the seed count can average 857 seeds per gram, an increased mass of over 100-fold.

Pelleting is ideal for mechanical seed metering/planting in direct field and protected culture applications. In the coastal and desert valleys of California and southwest Arizona (as in other agricultural areas), it is common to use precision belt, plate and vacuum planters.

Historically, the primary obstacle for successful seed pellet development has been slow and erratic germination associated with insufficient oxygen available to the seed. The development of a splitting pellet like our High-Density, Medium-Density or Light-Density lettuce pellets are especially beneficial to growers that plant lettuce under saturated soil-water conditions caused by frequent irrigation after sowing. A pellet that can split open upon hydration allows oxygenated water to move directly to the seed.

We’ve developed different pellet weights and densities to meet growers needs to “fine-tune” planting to varied soil and field conditions.

Protected culture planters are generally in a controlled indoor environment using vacuum drum seeders. Often these growers will opt for a lighter density pellet under these parameters.

Lighter pellets weigh less per unit volume (boxes and pails are packed by seed number), so shipping costs are lower and handling is easier.

Higher density pellets for precise drops. Pellet weight is a factor when considering certain soil conditions and tractor/planter speed.