I tried germinating lettuce outdoors and had a poor germination rate. Then I read somewhere that they may need light to germinate (I had buried them).

I grabbed a container with sifted compost I had lying around, watered it and threw some seed without covering them. I left it under the shade of a tree, with some sunlight but not direct.

Now, 3 or 4 days later, a few already have cotyledons so I need to expose them to more light so they wont get leggy. But the rest all have a radicle showing, and I am worried that more light may damage them.

Since most already germinated and have a radicle out, can I cover them with more soil? or more light wont damage them?

  • Black Seeded Simpson seed in particular needs light to germinate, there may be others. Commented Oct 18, 2019 at 15:09

2 Answers 2


Since they have mostly all germinated the important thing now is to keep the compost moist when you move the pot to a brighter location. Once they start sending down the root they will look after themselves as long as they have moisture.

Lettuce is a crop that will transplant which makes things easier. Once the early risers can be gently handled and moved to a more permanent location the rest will be able to handle the soil disturbance and quickly settle down and continue growing whether this is to produce cotyledons or get more robust. The key factor is available moisture at the soil surface.


I have always sown lettuce seed at a depth of about 1/2 inch (15mm) with no germination issues.

However, temperature is critical, and temperatures above 70F (20C) will reduce germination significantly.

The ideal temperature range is 60-70F (15-20C) though lettuce will germinate in temperatures as low as 40F (5C).

Lettuce also grows better at lower temperatures than in hot weather conditions.

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