8 Steps: How To Start Seeds Indoors With Grow Lights

Low bamboo garden with LED Grow light

Cultivating an indoor garden is an enjoyable project for many gardeners. In the winter, taking advantage of supplemental light to grow seedlings is an inexpensive way to help you start growing healthy plants.

It will provide you with much joy experimenting with different flavors, shapes, and colors. Besides, it allows you to enjoy your favorite edibles over a more extended period by planting varieties that mature at other times.

Starting your plants from seeds indoors may take a little effort, but it will give you a more comprehensive range of possibilities, even when stretching your gardening budget.

But some plants have different needs. And not only that, but some plants are best sown directly in the garden, which means not all plants should be started indoors.

The Comprehensive Guide To Start Seeds Indoors With Grow Lights

Tomato seedlings under a grow light
Image by: hortmag.com

Starting seeds is a pretty straightforward process. All you need is to understand the essential ingredients such as the growing medium, containers, light, warmth, water, your attention, and how to provide them all correctly.

If you are able to start seeds indoors successfully and are now looking for a high quality grow light for your seedlings, check out the following article: “8 Best Grow Lights For Seedlings”.

If you are a newbie to starting seeds indoors, it is smart to start small. Plant about three or four varieties to see and learn how it works.

1) Start Small

Seeds like tomatoes and marigolds are easy to start indoors. But each plant has unique seed-starting requirements. And to start small by growing just a few varieties will help beginners to start seeds successfully.

Plants like basil, zinnia, coleus, nasturtium, and cosmos are good choices for beginners. These are easy to grow, and knowing how they work will help you start fussy seeds without difficulty.

2) Know Your Seed

Packets of organic seeds
Image by: schoolgardening.rhs.org.uk

Getting the seeds ready to grow outside when the weather is favorable is the primary goal when starting seeds indoors.

Generally, there are thousands of different garden plants you could grow from seed.

However, if you are new to growing from seed, you may want to use a simple rule. And as you gain experience, you’ll gradually fine-tune what works best for your growing conditions and for the type of seed you want to grow.

  • A Simple Rule to Start Seeds

Most seeds germinates in 2 weeks, and gardeners usually start seeds 6 weeks before the last frost date.

You can start seeds for houseplants at any time, but you can extend for annuals and perennials to 8 weeks.

It will give you 4-6 weeks of actual growing time, enough time to put on growth and harden off for the seedlings to be ready when moved outside.

  • Follow Instructions in the Seed Packet
Detailed instructions on the back of the seed packet.
Image by: gardenerspath.com

Start by checking the seed packet. Usually, some instructions should tell you when to start seeds inside.

But some vegetables that germinate pretty quickly, such as beans, squash, and poppies are best sown directly into the soil. In the packet, these are often marked “direct sow.”

  • How Do I Find My Last Frost Date?

Seeds started indoors can’t take frost, which is why you can’t take them outside until all danger of frost passes.

Asking some expert local gardeners or leveraging online help will help you find the last frost date in your area. Also, there are many gardening groups you can Google to ask questions and get answers in real-time 24/7.

But sometimes, online help is often based on data from large cities. And if you are in a small town, the date for a large town may not be suitable for you.

Crowded large towns generate heat naturally, making the last frost date earlier than in nearby smaller towns.

Besides, the date has been moving with climate change. The last frost date you usually know for many years may not be the valid date for now.

So, asking some expert local gardeners can still be the best source of answer when it comes to knowing when is the last frost date in your area.

  • Seed Starting from Annuals

Colorful blooms of zinnia.

You can start seeds for annuals anytime with the 6-week rule, and it will definitely work. But some people want their annuals to flower soon after planting and get a long season of bloom.

If this is your primary goal, starting seeds for annuals quite early will give your plants enough time to harden off and grow with a size large enough to flower once you move into the garden.

  • Starting Seed From Perennials

Ox-eye daisy in white blooms

Perennials usually do not flower the first year from seed. Some plants produce a few blooms after the second year, but others do not.

Also, plants like peonies will take 5 years before they start to produce flowers. Because of these, seed starting for perennials too early is not necessary.

However, the “6 weeks before the last frost date” rule is still applicable to perennials.

Perennials can take a couple of months to germinate, so if you want to start seeds indoors, you’ll have a pretty good-sized plant by the time you want to move it when the weather is favorable outside.

  • The Stratification or Scarification Process
Hard coated seeds in a blue patterned plate
Image by: americanmeadows.com

Some seeds require either stratification or scarification to germinate.

For stratification, you need to soak the seed overnight in water and wrap it in moistened paper towels inside a plastic wrap for some time to stimulate germination.

Scarification is another process you can use for seeds that remain dormant for not absorbing water and oxygen due to thick seed coating.

Filing, creating an abrasion with the use of sandpaper, or the use of chemicals are techniques used to scarify the thick seed coating. This will allow water absorption and penetration of gas exchange to encourage germination.

  • Warm versus Cool Germination

Most seeds prefer warm temperatures to germinate. However, lettuces, greens, and peas do well in room temperature requiring no extra warmth.

 3) Use The Right Sowing Containers

Any container that is at least one or two inches deep that will hold the growing medium and has drainage holes will work to start seedlings. But there are specially designed seed starting kits you can purchase to grow vigorous, healthy seedlings.

  • Use Biodegradable Alternatives
Newly germinated seedlings in recyclable peat moss starter pots
Image by: plantcaretoday.com

However, if you have a minimal budget, DIY biodegradable seed starter pots like paper cups, egg cartons, eggshells, milk cartons, and toilet papers can make a great alternative. These materials break down easily in the soil.

Yes, these are free alternatives to start seeds, but the plants can quickly outgrow the space. Make sure to move them to larger pots before the roots begin to bound.

Also, poke holes for drainage and place them on a catching tray for water residual.

Using biodegradable seedling containers will allow you to plant them in the garden directly without disturbing the young plant’s roots.

This method will prevent the possibility of damaging roots during the transplant process, causing transplant shock.

  • One Type of Seed per Planting Station

Using just one type of seed per planting station will help you assess every plant’s needs efficiently.

Some seeds prefer to be sown on the surface of your potting mix, which means you need not cover them with soil at all.

Other seeds germinate fast when slightly covered with the mix as recommended on the seed packet.

Make sure to scatter small seeds evenly over the surface. For larger seeds, you can make holes with a pencil or finger to distribute evenly.

4) Prepare The Potting Mix

Seed starting potting mix in a carton egg tray
Image by: gardenworld.co.uk

Seedlings are exceptionally delicate, and for the best chance of success, it is wise to start them with a sterile, fresh seed starting mix. The mix should be light and fluffy and should be able to hold enough moisture.

Unsterilized growing mediums can cause disease issues, and compacted soil will hinder new roots in penetrating the soil to absorb nutrients.

Do not use soil from your garden or re-use potting soil from your houseplants. This will likely cause you failure right from the start of the process. These kinds of soils contain diseases that are harmful to your newly germinated seedlings.

5) Provide Warmth To Encourage Germination

Seed starting always happens in two stages: the germination and growing stage.

In the germination stage, this is when the root and leaves emerge from the seed. At this stage, the process occurs under the soil and what you need is a gentle warmth to encourage seeds into sprouting.

  • DIY Mini-Greenhouse Plastic Wraps
DIY Mini-Greenhouse Plastic Wraps
Image by: instructables.com

You can slip the container inside a plastic bag to trap heat and maintain humidity. The plastic bag will function as a mini-greenhouse for your seedlings.

Place the container pot on a warm spot about 70 to 75°F, or use a heating mat to maintain the warmth required and keep the humidity high.

However, remove the bag once the seeds have germinated to avoid developing any disease.

A warmer temperature will allow the seeds to germinate faster. But in cold winter months, providing supplemental warmth like heating mats can also make a difference to your seedlings’ health.

  • Take Advantage of Heating Mats
Seed starter tray with a heat mat
Image by: brooklynfarmgirl.com

Generally, a heating mat is not required, but it helps generate warmer soil and encourage seeds to germinate faster.

However, some seeds do not grow when the temperature gets too warm. Make sure to provide just the right warmth that the plant needs.

When considering using heating mats, remove the seedlings once germinated. Seedlings grow better below room temperature.

In the growing stage, when the sprouts reach about half an inch tall, that’s when the plant needs light to perform photosynthesis that gives it the energy to grow.

6) Provide Light

Seedlings growing healthy under grow light.
Image by: countyweeklynews.ca

The quality and amount of light regulates plant growth and development.

And depending on the type of plant you want to grow, each stage of cultivation and photoperiod required by the plants, the spectrum range, luminous efficacy, and color temperature are all essential for use with particular plants and periods.

Insufficient light can cause plants stunted growth and give out reduced pigmentation. Also, the plant will exhibit physiological differences concerned with the functioning of healthy growth.

Newly germinated seedlings need lots of light to grow healthy, and starting indoors with insufficient light can cause the plant’s unhealthy conditions.

  • The Role of Light in Plant Growth

As we all know, all greens need light to process food through photosynthesis. The plant’s cells will convert the energy from the light into sugars and give off oxygen as a by-product.

But plants vary in the light requirements to thrive. Houseplants like dracaenas do well in low-light conditions, while fruiting edibles like tomatoes require an ample amount of light to grow appropriately.

  • Grow Lights Suitable to Your Plants Needs

But if you don’t have a windowsill handy, you can use artificial plant lights that fall into the LED spectrum to ensure your plants will get the light they need during those shorter winter days.

There is a wide range of grow lights in the market from which to choose. You can either mount larger types from the ceiling or get the smallest countertop ones you can use.

But you need to understand that not all LED light sources contain the full spectrum of colors just like the sunlight. Sunlight has the full range of colors your plants need to use in different metabolic reactions to grow healthy.

  • Specific Ranges of the Light Spectrum

LED lights are designed in varying color chips to correspond to various kinds of plant demands. If you want a plant to grow tall, the LED spectrum raises the amount of yellow, far-red, green, and orange chips inside the lighting fixture.

However, overexposure to the amount of blue/UV colored chips can cause the plant stunted growth. Besides, the excessive blue range also affects both the chlorophyll content present in the plant and the leaf thickness.

  • The Color Temperature of the Best LED Grow Lights

The distribution of light given to plants is grouped in colors based on wavelength, also known as light quality.

Light quality can also be expressed as a red:blue ratio.

Photomorphogenesis, on the other hand, is the term for the plants response to the light spectrum.

Red and blue are the two most essential light colors in most LED grow lights. The plant needs red light to photosynthesize and inhibit abnormal stem elongation.

On the other hand, blue light stimulates the stomatal opening, leaf expansion, photoperiodic flowering, and many other functions.

The combination of red and blue lights is optimal for the plant’s growth cycle.

Also, the addition of other light colors like green may enhance the health advantages of your vegetation.

  • Is Regular LED Lights Suitable for Starting Seeds Indoors?
Regular household light
Image by: motherearthliving.com

The LED lights we typically used in our homes are ideal for illumination. They radiate energy and heat, but these aren’t enough to meet the plants’ demand for light, particularly when it comes to actually growing plants.

Non-plant-optimized LED lights or the regular household lights do not have the wavelengths in distinct ratios to provide the balanced lights the plant needs. And this insufficiency may limit the potential growth of your indoor plants.

  • Non-Plant-Optimized Lights is Inefficient for Plant’s Use

Indoor plant growers sometimes prefer to use regular LED lights when starting seeds because it is less expensive.

However, they need to spend more than they think. Indoor growers need to replace the LED bulbs more often because the lifespan isn’t designed like that of specialized LED grow lights.

Moreover, regular household lights for the plant will likely end up in an extended growing period and may result in low-quality yields.


Considering all the disadvantages above, using regular LED lights isn’t as beneficial as you think.

If you want to make the most of this exciting technology, choose the designed one for that specific purpose. Investing in grow lights when starting your seeds indoors can make a huge difference.

7) Water The Seedlings

Seeds must stay moist to germinate quickly. Check the potting mix regularly to ensure you’ll provide the water it needs. Spray with room temperature water when you find out the soil is drying out.

As the seedlings grow, water to keep the soil moist. You can use a handheld sprayer or mister to give the soil time to absorb plenty of moisture.

  • Water from Above
Watering a seed starter tray using a white plastic watering can.
Image by: finegardening.com

Watering from above is the most common method in watering seedlings. You can either use a mister or a spray to help you water with care. These are easy to use and won’t drive out new growth seedlings from the soil surface.

  • The Wick Watering System

Wicking is another way to water your seedlings. This method takes time to moisten the soil. However, it helps ensure your seedlings are well-watered if you need to go out for a day.

All you need is to place water in a plastic tray where you sit the seed container in. The water is soaked up through the wicks and the bottom holes to moisten the mix.

You can also take a bucket of water and place the wick to draw water into the plant. But remember not to overdo it, as it will encourage mold that can cause harm to your seedlings.

8) Feed Your Seedlings

Feeding your seedlings with liquid fertilizer a few weeks after the germination is also beneficial.

Feeding the seedlings with organic liquid fertilizer rich in Nitrogen will help develop new leaves and boost potential growth.

You can mix concentrated fertilizer into a gallon of water and bottom feed to the seedlings to prevent overwatering and the possibility of fungus problems.

Final Thoughts on How to Start Seeds Indoors with Grow Lights

Starting seeds indoors allows you to raise quality plants. Most varieties of vegetables and flowers are hybrids of high-quality seeds. Often, these seeds offer specific disease-resistant and unique characteristics.

But seeds like woody ornamental and native perennial plants need stratification or scarification to germinate. However, all seeds sprout quickly only in an environment conducive to germination.

Seeds germinate when provided with a warm environment but do well at optimum temperatures. For instance, tomato seeds germinate at temperatures between 50 and 95°F, but they do well with temperatures around 80°F.

Using germination flats like specific chambers or heating mats will help maintain ideal temperatures to encourage quick germination.

Although seeds differ in light requirements, the use of grow lights when starting seeds indoors will provide lights up to 18 hours a day. These are designed to meet the seedlings’ demand for growing healthy.

Providing an ideal germinating medium is also essential when starting seeds indoors. It should be well-aerated and loose. Besides, the soil must have the capacity to hold moisture during the germination process.

Choosing the right container for your seedlings is also another factor to consider when starting seeds indoors.

There are various types of pots and trays to choose from. You can also DIY seed starting containers with recycled materials easily found in your home.

Utilizing organic materials that break down easily helps reduce the risk of root injury when transplanting, particularly for plants with delicate root systems.

Another thing to remember is to avoid splashing on the seed container, which might displace small seeds. Hand watering seeds should be done with care.

And the use of plastic bags is also an effective way to achieve consistent moisture during germination.

You can slip the bag around the whole pot after the initial watering and let it function as a mini-greenhouse to trap heat and humidity in the process.

Some seedling trays readily available in the market come with clear plastic dome lids and panes of glass for this purpose.

And whatever approach you may like to use, make sure to remove the cover as soon as the first seedling leaves appear. Otherwise, newly sprouted seeds that prefer room temperature will be killed.

Have you started any seeds yet? If you have any questions, feel free to ask in the comment section below.

About Benita Abucejo

Hi there! My name is Benita Abucejo. What can I say? I truly love spending my days in the outdoors, specifically in the garden. Gardening has always been a strong passion of mine since I was a little girl. It has brought me so much joy and happiness that it is definitely safe to say that I will be a gardener for life. For a period of time, I was able to work with people who are into home gardening and I found it to be quite beneficial to my physical health, as well as my mental well-being. Here at Seasonal Preferences, I am going to share with you my experience and ideas so that you can fulfill yourself with the same satisfaction and happiness. Of course, if you have ideas, I would love to hear those as well! Being creative in the garden can really be quite fascinating so let's share our experiences and be the best gardeners we can be. With that being said, thank you for dropping by and please leave me a comment on one of my posts if you would like to get in touch!

View all posts by Benita Abucejo →

Leave a Reply

Your email address will not be published. Required fields are marked *