Growing plants from a seed is an extremely rewarding but time-consuming process. To set yourself and your seeds up for success, you have to be diligent every step of the way, starting with germination.
Germination is when the seed comes out of dormancy and starts to grow. Do seeds need light to germinate?
Yes, but not all of them need it at the same time and in the same way. There are many other factors to consider when trying to get a seed to germinate, but light is one of the most important.
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What is Germination?
Germination is the process in which the seed comes out of dormancy and begins growing its primary root, stem, and immature leaves. Effective germination requires a lot of things. What starts the process is when water softens and penetrates the seed coat.
The inside of most seeds contains starch that converts to sugar when it comes into contact with water. This sugar serves as the energy for the seed to start growing, putting out a root that grows down into the soil and a shoot that grows above the soil.
During this process, all of the energy needed for growth comes from the seed itself. But when the shoot reaches the surface of the soil and is exposed to sunlight, the shoot produces baby leaves that use sunlight to power photosynthesis, providing more energy to the growing seedling.
The germination process is generally complete when the first true leaf appears, at which point the plant is considered a seedling.
What Does a Seed Need to Germinate?
To start germinating, some plants prefer total darkness while others need light. That said, light is important for all plants at some point during germination because the sprout needs sunlight to survive, grow true leaves, and become a seedling.
Light is not generally one of the things that seeds need to begin germinating. What are the three things they need? Oxygen, water, and a warm temperature. These three things need to be properly balanced, or the seed may not germinate at all.
If there is too much water present, the seeds won’t get enough oxygen to germinate. If the balance of oxygen and water is perfect, but the temperature is too cold, the seeds won’t grow.
That said, there’s no magic ratio of oxygen, temperature, and water that works for all plant seeds. Each seed is different. For successful germination, you have to understand what each plant needs.
Now, back to light. Most seeds do not need light to begin germinating. Some need complete darkness while many will germinate regardless of how much light they have.
But there are a few that require light. These include ageratum, balloon flower, begonia, blanket flower, coleus, columbine, ficus trees, gerbera daisy, impatiens, lettuce, petunias, poppies, primrose, and snapdragons.
How Can You Tell Whether a Seed Needs Light to Germinate?
The best thing to do when planting a seed is to do your research so you know what each plant needs. That said, there is a way to determine whether a seed needs light to germinate. Look at the size.
Large seeds have more starch and therefore fuel inside of them and usually prefer to be buried deeper in the soil. They don’t need light as they don’t rely as heavily on photosynthesis. Small seeds, on the other hand, need light as soon as possible to continue growing.
Moisture and Light During Germination
If you’re planting seeds that require light to germinate, you will place them right on the top of the soil. This way, you know that they are getting the light they need. Planting seeds in this way is easier since you don’t have to worry about how far you place them under the surface, but keeping them moist in these conditions can be tricky.
When seeds are placed on the surface, they are easily disturbed by wind, heavy rain, and even animals walking through your garden. To protect them while still ensuring that they get the light they need to germinate, there are a few things you can do.
Covering the seeds lightly with plastic domes or plastic wrap is a good choice, especially for seeds you’re starting indoors. You can even tuck them inside a plastic bag with a moist paper towel to help them get started.
These methods are a little difficult if you’re planting outside, so you can also try covering them in a thin layer of ground vermiculite, just to make sure it’s suitable for gardening. Vermiculite is a mineral that is clear and retains water. It provides protection while keeping the seed moist and allowing sunlight to pass through.
Light and Continued Growth
Most seeds generally need light to help them grow from the first sprout and immature leaves to a seedling with its first true leaves. So, even if a seed does need light to begin to germinate, it will once it reaches the surface and attempts to grow into a mature plant.
But all plants need different amounts of light. Some do just fine living in the shade while others need bright, direct sunlight to thrive. And not just any light will do. Sunlight has many colors of the spectrum in it, and plants need different colors throughout their life cycle.
Red light and blue light are two of the most important. Plants use red light to stimulate greens and blue light to prevent overgrowth. A plant grown under only red light would likely get leggy without blue light to regulate water conservation and flowering.
Tips for Successful Germination
While some seeds germinate easily in just about any conditions, others take a little more time and attention. Here are some of the different conditions that shells need to germinate:
- Some seeds need a lot of attention to germinate while others don’t. For example, there is a unique type of pine that has seeds that won’t germinate unless they are exposed to fire, making them the first to regrow after a forest fire. Research your seeds to make sure you give them what you need.
- You can help some seeds germinate quickly by soaking them in water overnight or sanding the surface with sandpaper. Once the seeds are planted, water and oxygen can more easily penetrate the seed, leading to faster germination.
- Some seeds need to experience certain temperature fluctuations before they germinate. You may find some seeds, like apple and columbine, have to be placed in the fridge for some time before they can be planted outside. These conditions simulate the moist cold winter.
- Make sure your soil is evenly watered. Too much water can cause the seeds to rot and too little will prevent germination.
- Germination times vary dramatically according to what plant you’re growing. Some will sprout in only a few days while others can take weeks or even months.
This information may seem a little overwhelming, but once you get to know the seeds that you’re planting, it will become more clear.
When you get a new package of seeds, read the side carefully as it usually tells you exactly what the seed needs to thrive. Remember, every seed needs a different ratio of oxygen, water, and temperature to germinate. Some need light to get them started, but they all need light once they reach the surface.