tomato plants growing under indoor grow light

Using an Indoor Seed Starting Setup

by | Feb 20, 2024

As I’m writing this, there’s a steady rain pouring outside, which is truly my favorite weather for staying indoors and starting seeds in Winter. This indoor seed starting setup is something I’ve wanted for a long time, but finding space in my 700 square foot home was always a struggle. If you’ve been a longtime blog reader, you’ll know that I’ve tried a wide variety of seed starting setups over the years—outdoor cold frame, sunny window, hybrid variations, garage, etc.—and so, I’ve been really anxious to try a fully indoor seed starting setup.

Before I go on, I do want to clarify. There is not only one way to start seeds. If anything, my history is proof of that. Instead, I’d say that seed starting is very depending on our circumstances, resources, and lifestyles. For example, I didn’t feel comfortable devoting a whole room to seed starting in my small home, so that’s how I ended up with last year’s garage seed starting setup (which worked well for me). In fact, the main reason I’m switching to an indoor setup this year is because a) I hadn’t tried it before b) I wanted to be able to share and demonstrate one here on the blog and c) the garage experiences more temperature swings this time of year and is considerably colder than my house. My goal was to see if having a more compact, streamlined indoor seed starting setup would just make my life easier!

The Basics of an Indoor Seed Starting Setup

Today I’m starting some of my cut flowers indoors, along with tomatoes, peppers, and eggplants if desired. Since some of last year’s eggplants are still hanging out in the garden, I’m not really sure I want to plant more this year! Later next month is when I’ll start more seeds, and local gardeners can check out my personal seed schedule (available to subscribers of my email list) for more specifics.

Starting in January, I did a test run of this indoor seed starting setup and was really thrilled with the results (pictured below)! I grew various types of early Spring crops—like napa cabbage, kale, and more broccoli— to replenish the garden before our Summer growing season begins. Overall, I was very impressed by the quality of the seedlings and am excited to get some Summer seeds going finally!

To start, here’s a supply list for what I used to create this indoor seed starting setup:

Equipment for this indoor seed starting setup:

Greenhouse shelf

Grow lights

Timer for the lights

Heat mat and Thermostat Kit

Fan *the one we have is not available online, so I’ve linked a compatible one

Seed Cells/Trays/Pots (we love these Epic 6-Cell seed starting trays)

Watering trays

Optional: extension cords


early spring crops grown under indoor grow light

These are the early spring crops I started using this setup in January. I’m very happy with the results! Sorry for the awkward photo, as I only had photos on my phone and had to crop them weird to fit the blogpost.

Safety Considerations

Without going into lots of detail, yes, grow lights can be irritating and damaging to the eyes. For me personally, I’m also sensitive to bright lighting anyway. I’d avoid putting your setup in a room that will be used throughout the day and keep the grow light staring to a minimum 😉

You probably know that water and electricity don’t mix. If you are planning to use  a grow light in a humid or moist area, make sure to find one that is waterproof or rated for that type of setting (my home is not humid, nor do I plan to grow in that type of setting). Additionally, connecting to grounded outlets is important!

Lastly, be aware of the amount of heat emitted by your grow lights. Some emit more heat than others. Don’t keep flammable things nearby, and be careful of keeping your plants too close as they can burn. Each set of grow lights comes with manufacturer’s specs, so just be sure to read those.

Starting Summer Seeds Indoors

So, I really only use an indoor seed starting setup during the months of January-March/April. Aside from that, Southern California has great weather for doing a more hybrid type of seed starting if desired (outdoors during the day, indoors at night), or even fully outdoors during the early Summer and Fall (I’ve got a little grow-along over on my YouTube channel for that season). February is the month I typically start peppers—notorious for needing heat to germinate and can take a longer time to grow—and tomatoes and eggplants. Truly, I try not to rush warm weather crops. In my experience, starting too early has far more drawbacks than starting too late.

But today I’m going to use the rainy day and the desire to get this blogpost finished, as an excuse to start a large batch of seeds so I can demonstrate this really neat indoor seed setup and hopefully get you inspired for Summer gardening!

Let’s Assemble Everything & Start Seeds!

First and foremost, I chose this more compact greenhouse for my seed starting “shelf”.  Initially, I looked into buying metal shelving that I’ve seen a lot of people use for seed starting. Most of the sets I saw were either too expensive or too large for what I had in mind. Circling back to when I mentioned that seed starting isn’t “one size fits all,” remember that I’m a backyard gardener that doesn’t have the need to start hundreds or thousands of seedlings. Another thing I liked about the greenhouse is the size and amount of shelves. It fits really nicely in the corner of the room and is pretty compact. Additionally, I didn’t need something with wheels, but I also won’t say no to something being easily moveable.

Please note, I am not using the cover for the greenhouse. In my room, the cover would just be too warm and stifle airflow. 

a basic indoor seed starting setup

Here’s a little overview of our very basic indoor seed starting setup. It’s been previously tested with some early spring crops (and a few experimental tomatoes) but is now ready for summer seedlings!

Mounting the Grow Lights

In the past, LED grow lights used to be priced much higher than most fluorescent shop lights and there weren’t many options, so they felt inaccessible to the beginner or home gardener. Nowadays, there’s such a wide variety of grow lights on the market that will give you great results at almost every price point. Therefore, making a decision can feel a little more overwhelming. In today’s online world, I’d say sticking with reputable dealers that are highly rated with good reviews and feedback is a good place to start.

We went with 2 foot LED Grow Lights (24 watt, full spectrum) as our grow lights. They have been great. The only critique I have is that figuring out the light “spread” has been a learning curve. That is one drawback of light bars versus full coverage boxes, as you’ll have to space the light bars so that there isn’t a gap in light intensity which can cause your seedlings to bend, reach, or get leggy. On the other hand, I like the flexibility of working with smaller light components so I can piece together my setup in different ways. Does that make sense?

To mount our grow lights to the metal shelves, we used zip ties through the little metal installation clips. Remember, as your seedlings are growing, you’ll have to raise your grow lights. Many manufacturers have a certain distance they recommend for hanging above your plants, but you’ll also be able to see if your seedlings are growing leggy or looking deprived of light as time goes on. As I set up the indoor grow lights on the shelves today, I simply kept the zip tie at a longer length, and then adjusted the height once I filled my seed starting containers and place them on the shelf. This way, I knew how high my soil level was.

For this particular setup, I used three grow lights for one shelf. They plug into each other per the manufacturer’s specs.

indoor seed setup with heat mat

It ain’t the prettiest solution, but here are the grow lights mounted to the shelf with zip ties. You can also see that the heat mat doesn’t fit the shelf perfectly, but it still keeps everything warm and cozy.

Automating Your Indoor Seed Setup

Although you will still need to monitor your seedlings daily and water them, there are two things I do to automate my indoor seed setup. The first thing, a thermostat, is discussed below in combination with heat mats. The second item, a timer, is used to turn the lights on and off. Most seedlings benefit from 12-16 hours of light per day, so I plug my lights into a timer and set it to run the lights for about 14 hours.

Using Heat Mats & Thermostat for Gentle Heat Underneath

After setting up the shelf and my grow lights, I laid down my heat mat and attached the thermostat. Although one heat mat doesn’t fit perfectly on the entire shelf, the radiating heat will keep the area warm enough for my needs. As mentioned above, the addition of a thermostat keeps this setup super dialed-in and almost hands-off, as it will monitor the soil temperature and turn on/off as needed. Personally, I like to keep my soil at about 72-75 for seed germination, and will gradually lower the temperature as my seedlings mature and I prepare them for life out in the garden.

While heat mats aren’t always necessary (in my garage they were), I find that buying the heat mat and thermostat as a kit is super convenient and well worth the money. I do want to remind you to put the thermostat probe in the soil after you have filled your seed cells and put them on the heat mat! I’ve forgotten this simple detail before, and was basically measuring the temperature of the room! Haha

Filling Your Seed Trays, Containers, or Pots

Longtime readers, you know that I like to use epic 6-cell seed starting trays as my seed starting pots. This is because I can fit more on my shelves in a very streamlined way. For most circumstances, they work great. The only caveat is for fast-growing, large crops (ie. squashes, beans, etc) it might be less work to start in larger cells simply because you’ll have to up-pot sooner if you start in a small pot. Then again, if you start your seeds too early, up-potting will be inevitable!

Today I’m excited to start lots of flowers and my tomatoes and peppers. I’m using a bagged seed starting mix, but that’s just because I’m crunched for time. Feel free to peruse the wide array of seed starting soil options and choose what works best for you. Honestly, writing my Summer cut flower series really got me excited for bright Summer blooms and homegrown bouquets! It was just the motivator I needed to buy seeds and get started on this rainy day!

In case you need a refresher on seed starting, you can check out my seed starting basics post or feel free to ask questions below!

some extra equipment for indoor seed starting include a timer for lights and a fan for airflow

This is the timer we use for the lights (pictured on left), and the fan we have for airflow (pictured on right). Unfortunately, my mom gave me that fan and I can’t find the exact one online. It’s a USB fan that had a loop on top, so I took a zip tie and hung it from the shelf. Be sure your fan provides a very gentle breeze!

Other Seed Starting Accessories

You’ll also want some watering trays to hold your seed pots/cells. Sadly, I’ve still not bought proper watering trays like these! Instead, I’m still using the same old foil trays from seasons before. Nothing wrong with that, but just know that you’ll need some sort of tray (that is heat-safe) for watering your seedlings from below.

A fan for airflow! You won’t need airflow until your seeds have sprouted, but I like to have a small fan that will circulate air over the seedlings. With seedlings growing so close together, having some air flow can actually help prevent diseases from setting in, but most importantly a gently breeze will let your seedlings grow stronger stems. This is actually one of the five important tips for healthier, stronger seedlings that I’ve shared before. The fan in our current setup is a USB fan that my mom gave me for hot days, and I simply zip tied it to hang from the wire shelving because it came with a loop for hanging! Overall, you can setup a fan on a nearby table but just make sure it’s a very gentle breeze or check out this highly-rated, compatible fan.

Find What Works for You

Lastly, I need to provide a friendly reminder to harden off any seedlings you grow indoors before planting them out in the garden! This is imperative! If you’re curious about my hardening off process, it’s all outlined right here along with tips to prepare your seedlings for life outdoors.

If you’re just starting out learning to grow a garden from seed, definitely check out all the resources under “seed starting” and my YouTube channel for extra videos, tips, and ideas. Eventually, every gardener develops their own rhythm and seed starting preferences, so just use your powers of observation and make adjustments as you go! Today I started about 17 seed trays worth of seeds—-that’s the potential for just about a hundred plants sitting there under the lights! Even now, after years of gardening, this makes my heart leap and dance. You better believe I’ll be checking this setup every day until the very first seed pops up! Good luck with your own seed starting adventures!


  1. Rodrigo Banuelos

    Hola my friend! Hope you Sam and Pete have been well. Totally excited you have your grow light set up! Definitely been here long enough to know you’ve shared many different and helpful ways to start seeds as well as being cost friendly and they all work given the chance, so it’s nice to read you’ve come full circle (in a way) with this set up 🙂
    I’ll soon be catching up with everything on IG again so I’m looking forward to stopping by to see what growing out there 🙂 Stay safe out there my friends!

    • FreckledCalifornian

      Hi! I won’t deny that the grow lights have made seed starting quite convenient. I remember the days when I was moving my seedlings indoors and outdoors and letting them sit on the kitchen floor overnight. Whew! Hope you’re seed starting is going well. Looking forward to seeing your updates on Instagram!


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Urban gardening is my jam. I’m Randi, California girl who obsessively gardens to grow food and flowers around my urban home. Seasonal, simple living is what inspires me~ I hope it will inspire you too. Join me in crafting a life and home connected to the garden Read More>>>>

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