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When Do I Put My Seedlings Under Light? Follow 7 Easy Steps

Starting Seedlings

Do you love gardening? Having a garden full of flowers and vegetables can bring pleasure, but it is even more pleasurable when you start with the seeds and prepare these plants’ seedlings.

Is it hard to grow the plants right from the seeds stage? As a beginner, you need to learn as much as you can before taking this step.

When I first decided to start planting the seeds and seedlings, I did not have much idea. A friend told me to put the seedlings under light, and all I could ask him was, when do I put my seedlings under light, even though I did not know why the seedlings had to be put under the lights.

Once I started to read and learn more about it, I realized that it is relatively easy to grow plants from seeds with the right lighting and equipment.

Each plant has its starting requirements, and it is best to start with the easy ones. It is best to start with seeds of plants like basil, tomatoes, zinnia, etc., and then move on to more difficult ones.

Watch this video to learn more.

When Do I Put My Seedlings Under Light 1

From Seeds to Garden: The Seven Steps

We can break down the process of starting the seeds and taking them for transplantation in the garden into seven simple steps.

1. Correct Timing

Timing is essential because the seedlings should be ready to go outside for planting when the weather is right. Some seeds can be started outside because they don’t require much time to germinate. Some seed packets will have instructions about the right time.

2. Right Container

Any container is acceptable, as long as it is about 2 to 3 inches deep and has drainage holes. Some people even use milk cartons or paper cups for growing seedlings. You may also get a seed starting tray, which will make the whole process easier.

3. Potting Soil

Avoid using soil from your garden or reusing any soil from other houseplants. Get potting soil, which is meant for growing seedlings to ensure disease-free and healthy saplings.

Before filling the containers, moisten the soil lightly. You can add some liquid nutrient feed if the potting soil does not contain any.

4. Planting

How deep you should plant the seeds will depend on the type and variety of seeds. Some small ones can be sprinkled right on top of the soil surface, while the larger ones should be buried.

Moisten lightly with a mister or water can. To speed up germination, you can cover the pots with a plastic wrap or cover.

5. Right Nutrients

As you notice, the seedlings continue to water moderately, never letting the soil become soggy. You can use a fan to dry the soil if you see it getting too wet. Feed the saplings with fertilizers regularly as per instructions.

6. Light and Heat

Remember that new seedlings need a lot of light, so place the containers where you get a good exposure. Without sunlight, the seedlings may become weak. If you are growing under lights, then use a timer to ensure periods of darkness and light according to requirement.

7. Move the Seedlings Out

A gradual transition of the seedlings from inside to outside is better. Before you plan to set the seedlings in the garden for a week, you can place them in a partly shaded spot for a few hours.

Gradually, expose them more and more to sunlight and fresh air. This hardening off is good for the seedlings to grow into healthier plants.

When Do I Put My Seedlings Under Light 2

When Do I Put My Seedlings Under Light?

Light is as essential to plants as it is to humans. The proper growth and development of plants depend on many factors, but the light is probably the most important.

Plants convert this light energy into chemical energy and other nutrients for their growth. When the seeds start to sprout, it is an ideal time to give them light.

Giving seedlings light even before they start sprouting can provide them with a head start. For plants to flourish well, as soon as you notice the first sprouts, provide adequate growing light.

This requires some research and knowledge because inadequate or extra lighting may end up doing more harm.

How Far Or Near The Lights Should Be From The Seedlings?

When you eat more food than you need, then you feel uncomfortable. Similarly, how much light a plant gets will determine its health?

If you place the growing lights too close to the plants, it can burn them or even affect their heart. Hanging your lights too high can make the plants stretch and wither.

Apart from the right distance, the brightness of the lights is also an essential factor. Some lights offer more heat, while others provide more light and less heat.

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Different Types of Light Bulbs

There are many varieties of light bulbs to choose from, and each type has its pros and cons. See what works best for you and the seeds you are planting.

  • Incandescent: These include halogen bulbs and bulbs, which are still being used in many homes. They give out red light but are a poor blue light source, which results in the plant becoming spindly. They produce a lot of heat, and plants can burn out if placed too close.
  • Fluorescent: They produce 2 to 3 times more light than incandescent bulbs with the same amount of energy. These are relatively inexpensive but require heavy and bulky support, so it is not as easy to work with as LED lights.
  • White Bulbs: Cool white bulbs emit blue and greenish-yellow light, and plants under such lights may become stocky or stunted. Warm white bulbs emit more orange and red light, and such lights can turn the plants tall and spindly.
  • Full-spectrum fluorescent bulbs: These produce a balance of warm and cool lights similar to a solar spectrum. Though they are not energy-efficient, they make the right choice to grow for seedlings.
  • T5: They are fluorescent lamps that have a diameter of about 5/8 of an inch. They are much better than other fluorescent lights, and you may find them suitable for seedlings.
  • LED Grow Lamps: LED lights are mercury-free and are suitable for the environment. They produce light within a thin band. LEDs are highly energy-efficient but cost more than fluorescent lights. More and more people are now favoring LED lights for seedlings and plants.

Distance of The Lights from The Seedlings

  • LED: they generate less heat than fluorescent and HID lights but produce more light. It would be best if you hung them higher. Otherwise, the sprouts may get bleached. Keep the tray approximately 20 inches away from the lights.
  • HID: High-Intensity Discharge lights have a more comprehensive range and generate more heat. It is best to keep them at a distance of approximately 14 inches.
  • Fluorescent: they have the right balance between strength and spectrum. For new gardeners, fluorescent lights are most often recommended. They can be used for all types of seedlings and are best kept at a distance of 12 inches.

What’s the Best Option?

Though it depends mainly on personal preference, fluorescent or LED lamps will work best. They are not very expensive and will ensure that your plants get the right amount and intensity of light. The wattages of these lights also matter a lot and should be given careful consideration.

LED Grow Light for Indoor Plant
LED Grow Light for Indoor Plant

Frequently Asked Questions

Q. Should you give light to the seedlings?

A. Once a seed sprouts, it becomes a miniature plant. It requires an adequate amount of light. Seedlings need more light than fully-grown plants. As much as 16 to 18 hours of light a day is good. In the winter months, when starting seeds, additional light may be required.

Q. Should seedlings get 24 hours of light?

A. Yes, seedlings indeed require lots of light to grow healthy. However, they also need a period of darkness to thrive well. The lights should be left on for up to 12 to 16 hours a day, but then there should be complete darkness for the rest of the time.


Many people like to start with the seeds and grow their seedlings for transplanting. If you are going to do it indoors, then you need artificial lighting for ensuring healthy seedlings.

Knowing how to use the lights and what lights to use are crucial for the whole process. After reading this article, you will feel more confident about growing your seedlings. Feel free to share this information with others.

If you need more clarity or have any questions, then you can contact us by mail. Watching your seedlings grow into healthy plants can be both a proud and joyful moment.