Pretty Simple

You’ve seen those digital watches…plastic body, lots of functions. Looks fairly simple…only four buttons. Now…try to set the thing without the instructions. You end up pushing buttons at random until…just by chance, you hit the right combination and you set it. It seemed simple at first glance, but ends up being a little more complicated.

Seed priming is kind-of like that

	Priming in a bubbling liquid
	Priming in a solid granule
	Priming in a barrel or jar

Seed priming might seem simple. All you really have to do is 1. let the seed soak up some water, 2. let it sit in a friendly temperature until it’s close to germination, and then 3. dry the seed back down to original moisture levels. That’s it…pretty simple. (If you want to know why we prime seed in the first place, take a look at SeedTech Newsletter #4).

Maybe not so simple

The first problem is the logistics of scaling up. Going from small lab batches to commercial sized amounts is always an issue. It’s just different. You have to bring large amounts of seed to a specific moisture percent and maintain that exact moisture level over several days, which can be a challenge. Also, large masses of wet seed will produce heat which can damage seed. You have to control this heat. Plus…seed uses oxygen and gives off carbon dioxide as its priming. You have to make sure oxygen from the air is always available to the seed, and that carbon dioxide does not accumulate around the seed. In a large mass of seed this can also be a challenge. Then…after you figure out the logistics, you have to determine what each seed lot’s optimal priming moisture is (it can differ slightly form lot to lot), and how many days a particular seed lot should prime, for good results (this is different from lot to lot). Not so simple.

Here’s what some people do

Early on, people would place seed into a water solution with air bubbling through it. The water usually had a salt or a waxy polymer mixed into it to restrict seed water uptake to the optimal seed moisture content. This aquarium type of set-up would be placed into a temperature controlled room. The biggest draw back to this method was oxygen availability in the liquid, and limits to the quantity of seed that you could prime at one time. Later on, people placed seed in a barrel or jar and slowly rolled the seed while adding the correct amount of water. Rolling the seed exposed it to the cool air (controlling the heat given off by the seed), and also exposed the seed to the oxygen in the air as it rolled. Still another way was to mimic the soil, by adding a commercially produced solid granule to the seed and then adding water to the mix until the seed reaches the correct moisture. The granule provided enough space between seeds to allow for oxygen transfer, and also allowed the heat created by the seed to be transferred out of the system. No rolling is required for this method, but after the priming is complete the granule has to be screened out using normal screening equipment. As you can see, what looks simple to begin with may not be so simple in the end.

That’s it for now…see you next time