How viable are our hand-collected seeds?

Kathie and I often discussed the quality of our collected seeds. Would they grow when planted? Would the seeds germinate?

Seed germination tests are not that hard to do and in early January 2008 I set up number of tests.

Most prairie and savanna species need a period of cold moist conditions to overcome dormancy. I used conventional petri plates with warm absorbent paper (filter paper) in the bottom. 25 seeds were placed in each plate, which was wrapped in Saran and placed in the back of the refrigerator. In early January 2008 the plates were placed under lights (16 hours light; 8 hours dark), rewatered when necessary, and observed daily for germination.

Petri plate with germinated seeds of purple milkweed. The root comes out first. All the seeds have germinated. 2/15/2008

Seed germination tests

Species	State-listed	Seed Year	% germ #1	% germ #2	% germ both plates
Aureolaria		2007	20%	12%	16%
Butterfly MW BE		2007	60%	80%	70%
Butterfly MW PVC		2007	76%	92%	84%
Cacalia tuberosa	X	2005	11%	0%	3%
Cacalia tuberosa PVC	X	2007	8%	0%	4%
Eupatorium sessilifolium	X	2005	0%	0%	0%
Eupatorium sessilifolium	X	2007	4%	0%	2%
Eupatorium sessilifolium Parrish	X	2007	4%	0%	2%
Green MW BE		2007	96%	72%	84%
Indian grass		2007	56%	60%	58%
Little bluestem		2005	16%	16%	16%
Little bluestem		2007	12%	12%	12%
Napaea	X	2005	4%	0%	2%
Napaea	X	2007	4%	8%	6%
Poke MW PVC		2007	80%	92%	86%
Prairie dropseed forbs garden		2007	24%	20%	22%
Prenanthes crepidinia	X	2005	0%	0%	0%
Purple MW	X	2005	100%
Purple MW forbs garden	X	2007	100%	84%	92%
Sweet Indian plantain	X	2005	28%	28%	28%
Sweet Indian plantain	X	2007	12%	32%	22%
Taenidia integrifolium		2005	0%	0%	0%
Taenidia integrifolium PVC		2007	0%	0%	0%
Wood betony Mark		2007	0%	0%	0%
Yellow hyssop	X	2007	60%	44%	52%

BE: From Black Earth Rettenmund Prairie

PVC: From Pleasant Valley Conservancy

As the table shows, the milkweeds germinated very well, as did the grasses, but some of the other forbs germinated poorly or not at all. We confirmed some of these data with greenhouse studies in future years. Obviously, if the seeds do not germinate, the chance of getting plants from planted seeds is not good. However, with most species we generally plant a lot of seed, so if the % germination is only 1-2%, there is still chance of getting some plants started from seed.

The best approach for those poor germinators was to use the greenhouse. We planted large amounts of seeds in flats and put them under lights after cold, moist stratification. We transferred the few plants we got to tubes and raised plugs. Most of the plugs we transplanted to the field grew, and became established. This worked especially well for E. sessilifolium, one of the state-listed species.

Of course, every year will be different, depending on conditions at the time seed formation is taking place.