July 25, 2012

Germinating seeds: radicles

This week I wrote a very long email to a friend who is starting a garden - in Namibia!  She and her villagers are beginning gardeners.  At one point she wrote "the swiss chard seeds had little germination root thingys in the package."  Those little thingys are radicles, or embryonic roots, and I have been looking at a lot of them recently.  If they were in soil, and not on petri dishes, they would grow down.

Root hairs also collect water.  Cotyledons are embryonic leaves I'll write about them next.
Right now I'm germinating seeds in growth chambers to see how temperature affects germination rate.  It sounds fancy, but it really isn't.  Growth chambers look like refrigerators with a panel of dials to control temperature, humidity and light.  The only parameter I'm changing is temperature.  Right now the temperature is set at 75 degrees.  Next week I'll start over at 65 degrees and so on down to 35 degrees.

The wires and box are the temperature monitor.

The seeds go in petri dishes with wet filter paper.  Every day I look at each one to see how many seeds have sprouted.  It sounds labor intensive, but isn't.  Yesterday I had everything counted in 15 minutes!  Partly because most of the seeds have sprouted and partly because a huge storm descended on southern New Hampshire and I had left all the windows in my apartment wide open.  I expected a flood when I got home and was relieved at a broken flower pot. 

Seed, radicle and beginning cotyledons under the seed shell on the left.


  1. This looks like a great way to grow microgreens. I've never used petri dishes but just the kits which work well also.

    1. I think petri dishes would be a bit small for growing microgreens - plus the filter paper doesn't hold very much water, so once the plants get big(ish) they use up the water really quickly. A kit, or something with more substrate would probably be better (and maybe more accessible).