I always forget how long it takes for seedlings to grow. Two weeks ago, me and the team sowed a couple hundred pots with twelve different plant species. A bunch of them I had never worked with before. None of them I had germinated on soil before. This may sound odd, but in ecology it’s quite normal to mass germinate seeds on glass beads, and plant seedlings. Reduces loss of replicates due to failed germination, and it’s easier to standardize. For my experiment – investigating effects of artificial light at night – I wanted to have plants under the light treatments from their earliest growth. Sowing on soil this time.
Germination of the weedy herbaceous species I often work with usually takes anywhere between 3 days and two weeks, depending on the species. I’m used to seeing lots of green at day four already. This time it took until day seven to at least get a good idea of what worked and what didn’t. It was clear that some species germinated well, but that others didn’t. I was fine with it. Even one species would suffice. Any additional species would only make the experiment better.
So for a week, I have been staring at cotyledon stage plants – basically small stems with the leaves that are encapsulated inside the seed. These are often only a couple of millimeters in size. All week, it seemed as if nothing happened. Only one species, Trifolium pratense, churned out a small first true leaf in the first week after sowing. Everything else left me waiting for almost a week more. This morning, when I went to water the plants, it was like someone had changed my pots. Most seedlings were finally unfolding and blowing up their first, and sometimes even second pair of true leaves this morning. (Usually it goes much faster from there.) Finally! I thought it was never going to happen. Normally I don’t mind so much, as I’m flexible in my planning, but the climate chambers I work in for this experiment are pretty much constantly booked, and I need to be out by February 28th. I really can’t afford slow seedlings.
Now that things have picked up speed over the weekend, I’m confident that I will have things to measure by the end of the week. Data! That’s what we do all of it for after all.
The pictures below are of some of the species, taken Thursday and Friday, hence the plants still look quite tiny. It’s really quite a difference, even it’s just two or three days apart. I will share some updates with pictures later next week.
Robin Heinen 