Building a portable after-ripening bucket for relieving dormancy of small seed batches

By Orville C. Baldos, Joseph DeFrank and Scott B. Lukas

The control of both seed storage temperature and humidity is essential for optimizing dry after-ripening of seeds. Manipulating these factors to process small seed batches often require expensive equipment such as incubators and desiccators. To reduce cost, we have devised a portable after-ripening system made from readily accessible components, such as a 5-gallon (18.93 L) plastic bucket (with a screw top lid), bubble wrap insulation, silica gel-based desiccator and a seed germination heat mat (connected to a thermostat). To assess the storage conditions of the DIY (do-it-yourself) after-ripening system, dried seeds and awns of piligrass (Heteropogon contortus) were placed inside the bucket and stored for 12 months at the 30°C setting of the seed germination heat mat. Temperature and relative humidity during the storage period was monitored using a datalogger (Onset HOBO® UH100). Records obtained from the datalogger indicate that the bucket can maintain an average temperature of 30.92°C (standard deviation = 0.96°C) and an average humidity of 30.81% (standard deviation = 1.89%). A previous study on after-ripening of piligrass indicates that this storage condition falls under the ideal range of storage temperature (30°C) and storage humidities (12% to 50% eRH). Results of the first year of evaluation suggest that the DIY bucket can be used for small-scale after-ripening of piligrass seeds. The potential exists for the modification of the desiccant type and temperature settings to facilitate after-ripening in a greater range of species.

This recorded talk was originally presented as a poster at the National Native Seed Conference, February 13-16, 2017 at the Omni Shoreham Hotel, Washington, D.C.

Here's the link to download the poster:

The method described in this webinar was effective on tropical species, but might not be suitable for species from a different environment, without adjusting tempeature and humidity parameters.