Sunlight Germination

[roadrunner]

Some seeds require sunlight for germination. So is there a general rule of thumb for how long the seed must be exposed to sunlight, i.e. minimum exposure time?

 

[Beverly]

Are you starting the seeds inside, or outside? I guess you would want to start them outside either direct sowing or in starter pots given your warm climate. It should be warm enough and sunny enough where you are to start them outside with sunlight approximating where you will be planting the seedlings. I've never worried about exposure time and have assumed it means press the seeds onto the soil but leave them exposed to natural light. Direct sun is generally not a good idea for tender seedlings. Even my most sun loving little seedlings appreciate a little protection from direct sun until they establish some roots. Cosmos, Zinnias, Tithonia can tolerate direct sun. Depends on what seeds you are planting.

 

[ellefanningxp]

One can imagine the seed germinating in the pitch darkness

 

[roadrunner]

Are you starting the seeds inside, or outside? I guess you would want to start them outside either direct sowing or in starter pots given your warm climate. It should be warm enough and sunny enough where you are to start them outside with sunlight approximating where you will be planting the seedlings. I've never worried about exposure time and have assumed it means press the seeds onto the soil but leave them exposed to natural light. Direct sun is generally not a good idea for tender seedlings. Even my most sun loving little seedlings appreciate a little protection from direct sun until they establish some roots. Cosmos, Zinnias, Tithonia can tolerate direct sun. Depends on what seeds you are planting.

I always start outside. This is just something I've noticed with various seeding instructions and just a question that popped in my head, with the latest seeding instruction of my Mexican Sunflowers.

 

[roadrunner]

One can imagine the seed germinating in the pitch darkness

If you bury the seed a 1/2-inch in the soil, that's pretty much pitch darkness

 

[Beverly]

Mexican Sunflowers grow wild here and are called Tithonia (Tithonia rotundifolia). I wouldn't bury them 1/2" deep. Let me see, those have arrow shaped seeds. i planted them with the pointed end pushed in the soil and left the wide end level with the soil so they can germinate exposed to the sun. I've been growing them from seed in the garden on and off for 8 years. It is not really a sunflower but an Asteraceae. The butterflies love them.

 

[roadrunner]

That's basically what I did -- gently pressed them into the soil, leaving them exposed to the sunlight -- except I was too lazy to manipulate the little seed so only the pointed section was pressed in

 

[roadrunner]

BTW, I just found this link which talks about the topic. Funny, my last google search turned up nothing...it's all in the wording....... http://www.thompson-morgan.com/effect-of-light

 

[Beverly]

That's basically what I did -- gently pressed them into the soil, leaving them exposed to the sunlight -- except I was too lazy to manipulate the little seed so only the pointed section was pressed in

Oh, no,no,no,no it only works if the seed is inserted exactly perpendicular to the soil
Really, the seeds will be fine and they will love growing at your wild place

Oh, and thanks for the link.