Seed Starting: Epigeal and Hypogeal Germination

rain lily seedling
rain lily seedling

I come from a long line of peasants. Both of my parents were the first people in their families to leave their small mixed farms for life in the city.

Though they left farming behind, both of my parents took with them a love of the land. Our summers were spent visiting The Farm or on the road to go fishing or camping. So if loving the land wasn’t already encoded into my peasant blood lines I was given ample opportunities to learn to appreciate the natural world. I am grateful of that gift.

But as someone who spent more time in the city than in the country, I have had to actively seek out the kind of practical knowledge that my cousins probably all knew when they were toddlers — even the really simple stuff like seed germination.

The first of my foraged native seeds have started to germinate: the rain lilies and chile pequins. Watching their development inspired me to learn more.

I found out that plants have pretty much developed two germination strategies. Knowing about those strategies solved some small mysteries concerning why some seeds need to buried relatively deeply while others prefer to be lightly covered or sown in situ.

Epigeal Germination

The rain lily’s germination, as shown in the picture above, was epigeal. Given the right conditions (in this case: moisture), the seed began to grow. It pushed the beginnings of what will be the root down into the soil. The seed itself sprung up into the air.  When the seed cracked open, the cotyledon (seed leaf) was released and the tiny plant began photosynthesising right away.

The rain lily, a monocot, has only the long green grass-like thing. When a plant is a dicot, like the chile pequin, it displays two leaves. Given time, good care and some luck, both of these plants will develop true leaves and keep on growing.

Seeds that use epigeal germination tend to be smaller because they don’t need a lot of stored energy. Once the seed opens the plant gets to work right away. These seeds tend to come from plants that like a lot of sun and good rich soil. Most weeds — ahem pioneer species — use this strategy. These plants create small seeds — a lot of small seeds — to compete in the wild west of edge territories. That is why a plant like the dandelion has a huge puff ball of seeds. The more seeds produced, the more likely some will survive. It is tough going though. Even the seeds that manage to sprout are super vulnerable. With the seed leaves raised above ground the new plant can be damaged by temperature extremes or even eaten.

Seeing the epigeal germination of my seedlings gives me some clues about how to take care of them. I need to make sure they get a lot of light. They will also need to either be fertilized or given good rich soil or they may languish.

Hypogeal Germination

squirrel eating mastI once saw a Terrance McKenna quote that said something like: plants invented animals to do their work for them. If so, I think the pecan tree must have invented the squirrel. Squirrels spend an awful lot of time running around gathering pecan nuts and then caching them underground. That’s where the seeds want to be: deep underground in a dark and moist place. A lot of times the squirrels forget about their stashes and new pecan trees sprout.

Unlike plants like my rain lilies and chiles, the pecan’s cotyledon stays underground. It is kind of like the seed splits in two. The root grows down and the stem grows upward eventually producing true leaves above ground. With hypogeal germination, root development rather than photosynthesis becomes the priority.

Seeds that use hypogeal germination don’t need a lot of assistance from the environment to grow. They tend to be forest organisms able to tolerate poorer top soil (initially) and less light because the large seed contains a great deal of stored energy.

As far as I know none of the native seeds I gathered happen to be hypogeal but the non-native field poppy seeds I scattered around definitely were. They germinated quickly but I didn’t see any seed leaves; they started with true leaves right away.

If any of the native seeds I gathered are hypogeal they probably will be sturdier than my delicate rain lilies and chile peppers but they might need to be quickly and carefully transplanted to their permanent location to give their roots plenty of space to develop. I suspect they would have preferred being planted in their permanent positions rather than endure transplantation.

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8 thoughts on “Seed Starting: Epigeal and Hypogeal Germination

  1. Cruel, indeed–the warms spell has been hard to accept after the suggestions of cooler temperatures! Thanks for the botany lesson. I will not remember those terms (epigeal and hypogeal)–I just won’t. But the explanations square with my casual observations. Thanks for having the academic curiosity and fortitude to teach this important lesson.

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    1. haha And when the cold weather hits I will complain about that. I have so much to learn. I don’t really expect anyone to read these things. I write them to help me organize my thoughts but I appreciate the encouragement. =)

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  2. Datura are like that – they develop a deep tap root quickly and so are happiest when they start out wherever they are going to be growing as opposed to tolerating transplanting. That said, I bought a datura in a gallon pot and put it into the thin soil out front. I tried to give it a hole that will allow for a deep tap root to develop and I’m trying to give it just enough water to tolerate this last insult of heat and wind stress October wants to hand out. As to the rest of my seeds and seedlings to be? Keeping the soil moist has been a real challenge. Watching the skies now and hoping for fat wet clouds (Sorry, ACL goers!). Rrrrrrrrain!!!

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