Protocol for postharvest seed drying and storage using zeolite dessicant beads


Protocol on the use of zeolite dessicant drying beads to dry seeds and maintain them at low moisture contents during storage. Using dessicants such as the drying beads to absorb water from seeds will lower their moisture content and extend their storage lives.

Steps for setting up seed storage trials:

1. When handling beads, use a funnel to quickly pour the require weight of beads into airtight containers and seal them.

2. Estimate the ratio of bead weight to seed weight required based on the relative humidity of the air in which the seeds have been air-dried or stored.

3. Weight out the required amount of beads based on the chart and place into an airtight container.

4. Weight out subsamples of cleaned seed containing sufficient seeds for planned germination and moisture content tests. Place the samples inside a paper envelope and store this in the container with the beads.

5. Place a small packet of indicator silica gel over the seed and quickly seal the container.

6. Prepare a similar set of seed samples and place in an airtight container without beads to serve as the control treatment.

7. Place both containers in the storage location. Remove seed packets from both containers periodically (at least every 2 months) to test for seed quality.

8. If the indicator silica gel changes color, remove the exhausted beads and replace with activated (dry) beads.

Reactivation of beads:

Once beads have absorbed approximately 18-20% of their initial weight in water, they can be reactivated by heating.

1. Place beads into metal can or a flat tray. Heat for 2 hours at a minimum of 250°C in an oven. Carefully remove the metal can or tray and place on a heat-resistant surface. Quickly cap airtight and allow to cool.


Drying beads