Jim:
I read with interest the comment that seed should be dried to 2% instead of 5%. In the PDF article that was referenced to support the 2% claim, the only research that was done was conducted on the small onion seed.
My effort to document this 2% value using the internet was not successful. The only other research data that I found on the internet recommends a moisture range of 6% to 13%, which is pretty close to the research values generated by Dr. James Harrington (the individual mentioned in my original article).
The research I found on the internet was conducted by the Oregon State University and it was based on a variety of grass seeds with comparisons to other seeds such as corn and soybeans (not just onions).
It might be helpful if the individual who indicated that the 5% value was incorrect could support the preferred 2% value with something other than a single research effort on one type of very small seed. I am always willing to update my knowledge base and I would be very pleased to see any additional research that supports this 2% value. I personally do not have any research experience with the precision drying of seeds and my information is therefore second hand. However, the information I have seen suggests that larger seeds (corn, beans, etc.) may crack if the moisture content drops below 5% and the seed will be lost. The above referenced internet article quotes a higher value of 6%, which is even more conservative.
Any information your other source can provide about the 2% moisture content for seeds would be very much appreciated. Respectfully, – Grandpappy