# Seeds

**URL:** <https://boards.straightdope.com/t/seeds/26341>\
**Category:** Factual Questions\
**Created:** [July 21, 2000, 1:09pm UTC](https://boards.straightdope.com/t/seeds/26341 "2000-07-21T13:09:47Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Debbie](https://avatars.discourse-cdn.com/v4/letter/d/90ced4/32.png) [@Debbie](https://boards.straightdope.com/u/Debbie)\
**Post date:** [July 21, 2000, 1:09pm UTC](https://boards.straightdope.com/t/seeds/26341/1 "2000-07-21T13:09:47Z")

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How do seeds in the ground know which way is down in order to grow roots in the right direction?

Debbie

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**Author:** ![Coldfire](https://avatars.discourse-cdn.com/v4/letter/c/a587f6/32.png) [@Coldfire](https://boards.straightdope.com/u/Coldfire)\
**Post date:** [July 21, 2000, 1:11pm UTC](https://boards.straightdope.com/t/seeds/26341/2 "2000-07-21T13:11:23Z")

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Welcome aboard, Debbie!

I’m not much of a biologist myself, but my WAG would be that they grow towards the sunlight/warmth.

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**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\
**Post date:** [July 21, 2000, 1:32pm UTC](https://boards.straightdope.com/t/seeds/26341/3 "2000-07-21T13:32:06Z")

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Not light, but gravity. See [http://www.newton.dep.anl.gov/askasci/bio99/bio99441.htm](http://www.newton.dep.anl.gov/askasci/bio99/bio99441.htm)

> [@](#):
>
> Answer 1: Plants don’t know where the light is, they do respond to gravity. Since  
> light is usually up, a plant seed grows up and finds light enough to keep things going.  
> Psych  
> Answer 2: One way that plants below ground can tell which way is up is with the use  
> of STATOLITHS. Statoliths are dense pieces of material that settle to the bottom of  
> a STATOCYST. In plants, pieces of starch or another material denser than water will  
> settle to the bottom of the cell. Somehow the plant cell determines on what side the  
> statolith has fallen, and then somehow relays a message (probably a chemical) that  
> tells the bottom cells to grow faster than the top cells, therefore causing upward  
> growth. There is still quite a lot of mystery in there to be discovered. I got this  
> explanation from BIOLOGY by Neil Campbell. This is similar to the way in which plants  
> use chemical signals to help them grow towards light.

Welcome to the SDMB, **Debbie**.

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**Author:** ![Phobos](https://avatars.discourse-cdn.com/v4/letter/p/3d9bf3/32.png) [@Phobos](https://boards.straightdope.com/u/Phobos)\
**Post date:** [July 21, 2000, 2:18pm UTC](https://boards.straightdope.com/t/seeds/26341/4 "2000-07-21T14:18:35Z")

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I think it may be gravity too. Hasn’t there been experiments on the space shuttle with growing seeds? I don’t know what the results were.

Then again, many seeds aren’t buried. So light may be the answer too.

Perhaps it depends on the plant species.

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**Author:** ![Debbie](https://avatars.discourse-cdn.com/v4/letter/d/90ced4/32.png) [@Debbie](https://boards.straightdope.com/u/Debbie)\
**Post date:** [July 22, 2000, 1:31am UTC](https://boards.straightdope.com/t/seeds/26341/5 "2000-07-22T01:31:38Z")

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Thanks for the welcome and the answers to something that’s been bugging me for a long time (ever since I read a story called “Seeds Grow” to my kids)!

Debbie