While researching strawberry germination I ran across references to the effect of far red light on germination. The reference says that far red light inhibits germination of lettuce but enhances strawberry germination. I filed it in the back of my mind. It was in the file named “How can that be possible?”.
In a recent test, I was looking at a variety of germination aids. I do germination trials in petri dishes. All the petri dishes for the trial was placed under the lights we use to grow indoors. It so happens that we are doing a light test at the same time. We are alternating LED lights with single tube T5’s that have 2700k bulbs (these are REALLY far red, around 1073 nm if my calculations are correct).
Normally I don’t even look at the petri dishes for germinating seeds for 6 or 7 days. After years of experience this is the earliest that I’d expect germ. I do check the dishes to make sure they have not dried out though. Low and behold, I started seeing germination on the 3rd day. Not just one seed here and there, but dozens of seeds from most of the selections (varieties). It then dawned on me about the far red lights. The germination tests had accidentally been exposed to conditions that were not planned out.
Since then more online research has uncovered some pretty interesting info. It seems that most references to the far red spectrum mean around 700+ nm. I have some 4100k T5 bulbs that I’m going to try another germ test, this one with fewer surprises, hopefully.
I will also mention that I allowed the germ tests to finish under these lights. It turns out that almost all selections had excellent germination and that germination was complete in 2 weeks. This is about half the time we allow for these tests. There are always straglers. Not only did the lights affect the onset of germination, it accelerated it. One should not jump to conclusions like this after one trial but I now have enough info to warrant more testing.