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Why do seedlings roots grow down and growing tip grow up and does it matter therefore which way round I plant my seed?

From germination roots grow downwards and shoots grow upwards. A germinating seed can be turned upside down several times and the root will still start to bend downwards. This behavior is an example of a tropism, a movement triggered by a stimulus.

The tropism that affects root growth is Geo-tropism. This is the affect gravity has on the plant, making roots grow downwards.

"It is not the soil’s humidity that causes the direction of the root, since the root will grow downwards and the shoot will grow upwards even if the plant is placed in an earth-filled tube where the upper part is moist and the lower is dry. If the plant is put into a water-filled tube the lower part of which is exposed to light while the upper is darkened, the direction of growth will still not change: a proof that it is independent of light." (A. de Candolle, 1834/38)

A. Knight (1806)showed that the direction of root growth is controlled by gravity. Seedlings were fixed on a vertically standing wheel that was turning around its axis causing a centrifugal force. At a fast rotation grew all roots outwards (in the direction of the centrifugal force), at a low rotation did they grow in an angle of about 45° (the result of both centrifugal force and gravity).

Knight thought at first that the root tips where pulled downwards by their own weight, but this assumption was soon refuted, since the downward movement occurs also when the weight of the root tips was compensated for by an opposite weight (Johnson, 1828).

A. B. Franck introduced the term Geo-tropism in 1868 and distinguished three types:

• Positive Geo-tropism (roots growing downwards with gravity)
• Negative Geo-tropism (shoots growing upwards against gravity)
• Transversal Geo-tropism (sidewards growth)

An noted from: Hamburg University Biology Department

As we can see from the above, root growth is stimulated by Geo-tropism and initial shoot growth by negative Geo-tropism rather than just photo-tropism, so no, it doesn't REALLY matter which way round the seed goes though it is beneficial to align it right just to save it energy bending.

How much light does my seedling need?

Flouro's are extremely useful for cloning and seedlings. MH/HPS can be too intense for these early stages of growth as the plants cannot absorb water fast enough (developing root system) to equalize the amount being lost through transpiration through the plants foliage (or at least that's my way - if you do use MH/HPS for your seeders/clones keep the lights a decent distance away, particularly for clones).

My seedlings have s t r e t c h e d, HELP?
If your seedlings have stretched you can always pot them into a deeper pot and bury them deep, almost up to the first set of seed leaves, new roots may begin to form from this buried section of the meristem.

If that's not possible, stake it gently.

You can also do something preventative, put a small fan in with them, not really strong, just enough to move them a little, this will help thicken the stem.

When should I pot up my seedlings?

When - Gotta let those roots grow strong

How do I pot my seedlings up?
Potting Up - How to transplant indoors
Transplanting - How to transplant outdoors

Coaster13

I'm in the germination stage and have placed my seeds in the tray method. Do I continue to water while in germination or do I leave the cover sheet alone. Also, should I place the tray under my flouro's?

Coaster13

Thank you very much my friend.

MARTINSTATIC

I've put my germinated seeds in their soils last night, and I won't be getting my lights for 2 more days.
Whilst under the soil. do they need that much light?
I can give them a few hours during the day of sunlight, but sunlight is pretty lame here.
I'm just worried if they die out in the next couple of days before I get my lights

Coaster13

They should be fine, just keep your soil moist for the time being. Good luck to you.

MARTINSTATIC

Cheers

MARTINSTATIC

Just thought I'd update, the sun is shining well today, so I've had them on the windowsill all day, got a nice bit of sun, and roots have come up a little and turned back down again which is fine, but part of one of them is a little pink. Is this ok? I watered them a bit, but don't wanna over water.
Thanks in advance and god (or whoever) bless you all for this forum.
I've been a member for 3 years, and only started posting yesterday :P

Kushbush

Can this happen without any males around I'm stumped all females did not see any hermies. Is this possible? and there are only a couple seeds on big big cola.

Coaster13

I'm not sure if I'm trackong you right. Anything is possible. If you have all females..congrats.:c ool:

MARTINSTATIC

I think he was saying he found seeds without any males around.
Sorry man they must have gotten pollinated somehow...Eitherway good luck breeding females, right now I'm just happy mine are still alive. (Transplanted 3 into larger pots yesterday, hope to fuck they don't die from shock).

Coaster13

No worries my friend, remember, it's a weed and it can take quite a bit of punishment. Did you see the stretch I put on mine? I'm amazed any of them survived at all. Good luck and hang in there!

i love ganj

you have your own thread fool. and they're called hermaphrodites

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