Do Seeds Need Light or Dark to Germinate? Garden Tips 2024

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Planting seeds should be easy. Simply stick them in the ground. But different seeds need different conditions, especially when it comes to how much light they are exposed to after they are planted.

Do seeds need light or dark to germinate: Generally, if you have larger seeds then they need more darkness to germinate while smaller seeds need more light. Some seeds that are tiny, like lettuce and grass, don’t need any darkness and can be sprinkled on top of the soil. Others, like onions and nasturtiums, need to be planted deeper. Try to plant seeds at a depth of three times their diameter.

Light in Soil

First, let’s explain that we are talking about the amount of light that can penetrate through the soil. We aren’t talking about whether you leave your seeds out of the package or in the package.

On their own, seeds won’t start to germinate if they are simply taken out of their package. Instead, they need a combination of light, water, oxygen, and nutrients (which are usually provided through the soil).

So, if you’re suddenly worried that you removed your seeds early from their package and now won’t germinate, you can breathe easier. Your seeds will remain in a dormant state until they are actually planted.

What seeds need light to germinate?

Have you ever been amazed that new plants pop up, even though you didn’t plant them? This is because seeds from old plants fell to the ground and, as they require little soil, they were still able to grow.

Here are some common seeds that don’t need a lot of light to germinate and can be planted either on top of soil or under a very thin layer.


Lettuce seeds are very tiny and can easily be swept away by the wind. Their tiny size, however, means they need very little soil on top of them or else they won’t have access to any light.

When sowing lettuce seeds, it’s easiest to spread them out where you want them to, right on top of the soil. You can then either water them or gently pat them into the soil to help them stay where they are and not be blown away or flooded away.


If you are trying to grow roses straight from seed, you will want to expose them to as much light as possible. Place your rose seeds on the soil and to help them out, cover them with a very thin layer of vermiculite, which has plenty of nutrients in it.

Keep your soil moist but not muddy to help roses germinate. The process can take a few weeks, so try to keep patient.


An easy flower to grow, poppies are very good at self-seeding. After a poppy is done blooming, a seed pod will be visible.

If you crush that seed pod upright in your garden, you will have an abundance of poppies the following year. This is a great activity to do with children.

What seeds need the dark to germinate?

The basic rule with planting seeds is that the larger they are, the deeper they need to be. These seeds all need an inch or two of soil on top of them to germinate. However, be sure to read each individual seed package for exact instructions.

Here are some seeds that need plenty of dark for the germination process. These will need to be planted at a decent depth to help them grow.


Nasturtiums have quite large seeds, usually around the size of peas. These need to be covered in two to three inches of soil as they love the dark.


Even though smaller varieties of sunflowers don’t require a lot of dark for their seeds, giant varieties do. Plant them about two inches deep to give them the darkness they need to germinate.


Generally, any type of seed from the allium family will require dark to germinate. Their seed casings are thick and require darkness to germinate.

If you’re starting onions indoors, you can actually place a plastic layer over the dirt to help with the darkness. Just be sure to remove it once the onions start to sprout.

How Do You help seeds germinate?


Some seeds, such as grass seeds, don’t actually need to be planted. Instead, you can simply scatter the seeds on dirt and they will start to germinate.

The trick, however, is that these seeds need to be kept continually moist. If they start to dry out, the germination process will be ruined.

Any time you put seeds down that don’t require soil, you will need to be vigilant in the first two weeks about keeping the area moist.

Don’t drown out your seeds as they can wash away. Instead, set up a drip system or a misting sprinkler and run it often.

As the seeds and the soil beneath becoming moist, the germination process will happen and tiny roots will form. The moister the soil is, the easier it will be for the roots to find their way through the soil.

Finally, the softer the ground is, the more likely the seeds will naturally compress into the soil. You can even gently walk over the freshly sown seeds to help tuck them into the top layer of the soil. Just do this immediately after planting so you don’t disturb any roots later on.


Whether you are planting seeds deep into the soil or merely sprinkling them on top of the soil, seeds need nutrients to germinate.

Start with soil that has organic matter that will provide more nutrients. You can also add a layer of vermiculite, which is a natural mineral that has the added benefit of retaining moisture.

If you start with hard, clay-based soil, it can be hard for seeds to break through, which will either stunt their growth or cause them to not germinate at all.


The smaller the seed, the more exposure to sunlight it needs. Plant smaller seeds closer to the surface of your soil, or even on top of it, while larger seeds need to be planted about three times deeper than their diameter.

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