RHA Newsletter 3(3): 5 (1972)
by Paul Jerabek

I have long known that unripe seeds germinate very poorly, if at all. I have also found that green pods can be ripened considerably under fluorescent lights if picked with stems and some foliage and placed in damp perlite.

While gathering seeds in the J. J. Kern Nursery last fall and seeing many green pods on the varieties "Blue Moon" and "Prima Ballerina", I decided to run tests without stems. Pods of each variety were carefully divided into 3 samples. One sample was shelled immediately, refrigerated at 36F. in a plastic bag for 30 days then planted. A second sample was placed in wet sand in a plastic bag in the garage and left till freezing weather threatened (24 days), shelled, refrigerated as above and planted. The third sample was placed on damp perlite under fluorescent lights (on for 16 hours/day) and left until all had turned black or showed appreciable dehydration (18 days), shelled, refrigerated and planted as above. Floaters were discarded and the third treatment increased "floaters" markedly. In spite of this there was a rather startling increase in germination as shown below:

Blue Moon #1: Shelled, refrig. at 36°F. 30 days. 830 0
Blue Moon #2: Wet sand in garage in plastic bags 24 days; Then shelled & Refrig. 30 days. 870 0
Blue Moon #3: Under lights on damp perlite 18 days; shelled & refrig. 30 days. 200 13
Prima Ballerina #1: Shelled, refrig. at 36°F. for 30 days. 192 0
Prima Ballerina #2: Wet sand in garage (24 days in plastic bags; Then shelled and refrig. 30 days) 196 4
Prima Ballerina #3: Under lights on damp perlite 18 days; shelled and refrig. 30 days. 136 29


Storage in wet sand may have a slight beneficial effect on unripe seed pods but storage under fluorescent lights appears to have a definite beneficial effect.

The big question mark in this experiment is whether results could have been merely coincidental with somewhat riper seeds getting into the third sample in each case.

This year I hope to cut green pods with stems and treat them under fluorescent lights while standing in water. The difficulty in drawing quantitative conclusions is that there is no way I know of to determine just how green your seeds are.