How to Create a DIY Seed Starting System (11 Must-Have Supplies)

Do you want to start flower and vegetable seeds but don’t have a greenhouse? No problem! You can create your own DIY seed-starting system indoors! Follow along with Part 2 of this informative Grow With Me series that details your must-have indoor seed starting supplies.

In Part 1, we covered the basics and provided a general overview of how to start seeds indoors without a greenhouse.

And today, in Part 2 of this Grow With Me series, we will cover the seed starting supplies you’ll need and what I use to start my own seeds indoors without a greenhouse.

While you can purchase a pre-made seed start system, it’s pretty easy to make a DIY seed starting system on your own as well. Wait until you see how we made our seed starting system in the basement and sunroom.

So let’s get started!

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Why Start Seeds Indoors?

If you’re researching DIY seed starting systems, then chances are you already know why starting seeds indoors is so important. But just to make sure we’re on the same page, here are a few reasons why I start seeds indoors each winter (and you should too!)

1. Get a head start: Starting your seeds indoors lets you start your growing season earlier, especially if you live in a colder climate zone like I do.
2. Give seeds a controlled environment: Starting seeds indoors also gives you full control over the first several weeks of their life, ensuring they get the best possible temperature, light and moisture for sprouting. This strong start can lead to more robust seedlings – and healthier plants!
3. Save money: While there is an investment to build a DIY seed starting system, once you’ve got your set-up in place you can save money year after year by buying seeds instead of seedlings.
4. Optimize plant growing time: When you aren’t dependent on warming temperatures outdoors, you can start your seeds early enough to ensure the plants are ready for blooming and harvesting when you want them to be.

11 Must-Have Indoor Seed Starting Supplies

I’ll deep dive into specifically what we did to create our own DIY seed starting system, but in general, you need to buy the following items to successfully start seeds indoors.

• Seeds
• Vermiculite
• Seed Starting Potting Soil
• Seed Trays
• Bottom or Drainage Trays
• Clear Dome Lids
• Grow Lights
• Table or Shelf System for Seedlings
• Heat Mat
• Plant Labels
• Oscillating Fan
• Programmable Timer

Since I have some space to work with, we chose to work with 4′ grow light systems. But there are smaller options available so design a system that works best for you and the space you have.

My DIY Indoor Seed Starting System

In my old house, I started seeds in my basement. Here in my newer home, I start them in my sunroom.

While it’s brighter in my sunroom than the basements, I still use the grow lights because there’s not enough daylight here to get the seeds started effectively without them.

Whatever DIY seed-starting system you choose, you’ll want to make sure that you have the ability to adjust the grow lights. Because as those seedlings grow, you’ll need to move the lights to keep them about an inch away from the tallest seedling.

There are a few ways you can design a seed starting system, but here’s how we did ours and I love it.

How to Create a Seed-Starting Shelf System

While I initially wanted to purchase a pre-made shelf system, they were a little more expensive than we cared to spend. And looking back, I don’t regret DIY’ng our own.

When I first started with this system, I was planning to start 21 seed trays. I needed more more space than those pre-made systems could provide without spending a ton of money anyway, so DIY’ing our own was the way to go.

Chris considered building shelves with wood, which is a great option. But for us and how we use our indoor living spaces the rest of the year, that would be more difficult to move around or put away when we are done starting seeds.

So we ultimately decided on these tiered wired chef shelves.They are perfect for starting several seed trays. It’s easy to hang grow lights on them. The shelves are adjustable.

Plus we can use them for more than just growing seeds. So this was a no-brainer. To accommodate roughly (21) 10″x 20″ seed trays, we bought two sets of shelves.

The Best Grow Lights for a DIY Seed Starting System

Next up was purchasing the grow lights. Home Depot did not have 4-footers in the store, so we bought as many 2-foot ones as they had in stock. And then I just purchased more online.

You can also find these at other big box stores like Lowes or Amazon too, but we went in-store at Home Depot to find everything.

The grow lights are pretty easy to use, came with a wire to raise and lower the lights, and will work well with the chef shelf system.

Since I couldn’t find more 2-footers online, I purchased a few 4-foot grow lights. And because I needed so many supplies, I had a feeling I would have to piecemeal some of them together.

It should all work out in the end, but of course, I would rather have all of the same supplies.

The Best Indoor Seed Starting Trays, Clear Domes, and Irrigation Trays

Home Depot did not have much aside from these complete seed-starting systems. But I found the larger ones with 72 cells that have a self-watering tray and peat pot cells.

I’ve worked with them before when starting seeds, so I bought a bunch to use.

And as an aside, let me tell you, if you can buy the self-watering tray ones, get those. It’s much easier to bottom water your seedlings this way.

Because there was little in-store stock, I purchased what was available based on my needs and purchased other items online.

In addition to the complete systems, I’m using some containers I have from last year. If you want to reuse containers you already have too, make sure you properly clean them.

And, I ordered 4″ deep biodegradable cells, clear plastic dome and irrigation trays too. The reason I purchased the 4″ deep biodegradable cells is because there are a few seeds that need deeper cells to start and grow in.

Seed Starting Soil and Vermiculite

For the cells/pots that do not have a seed starting mix in them, I purchased seed starting soil so I’m ready to go when it’s time to sow.

Some growers recommend using vermiculite to cover seeds after planting instead of soil. It’s not necessary if you don’t have it, but the seeds have an easier time growing through it.

And after having done this several times, I prefer the vermiculite.

Soil quality can make or break any garden, so I can’t stress enough the importance of good quality, healthy soil.

Heat Mats for Starting Seeds Indoors

I couldn’t find any heat mats in-store at Home Depot. So I just ordered them online. These are the heat maps I purchased.

Keep in mind that you don’t necessarily need the same number of heat mats as you do cell trays. Figure out how many heat mats you need based on the most seed packets you’ll be starting at one time.

I did not do this and totally overbought heat mats. So don’t make the same mistake I did and save yourself a few dollars.

Plant Labels and Sharpie

I can’t stress enough how important it is to label EVERYTHING you plant right after sowing. You’ll never remember the name and variety later so do yourself a favor and label it when you sow.

These are the plant tags I’m using. To write on them, I’m just using a Sharpie. But a pencil would work too.

Ultimately, you want to use something that won’t rub off too, so keep that in mind with whatever you decide to use.

Programmable Timers

Because we are starting seeds indoors without a greenhouse, it’s important to make sure the seedlings are getting the proper amount of light each day. In general, grow lights will be on for 14-16 hour days.

I don’t know about you, but I’ll never remember to turn them on and off every day, so a programmable timer is an essential part of a DIY seed starting system.

I’m using programmable timer and I bought two – one for each shelf system.

Power Strip

Since I am starting several shelves of grow lights on two separate programmable timers, I need to use a power strip for each shelf system.

This is the power strip I’m using – but you can use anyone that you have on hand.

Oscillating Fan

To help promote good air circulation in your seed starting space, it’s best to run an oscillating fan on low.

Seeds to Start Indoors

It’s almost time to start planting certain flower varieties, so I already have my seeds.

If you don’t have yours yet, check with your local nursery, big box store, or reputable online retailers like Floret Flowers, Johnny’s Selected Seeds, Renee’s Garden, and Burpees.

Next up in the series, we’ll be chatting about how to get organized before starting seeds indoors.

Common Questions Creating a DIY Seed Starting System

What is the cheapest way to start seeds indoors?

If you do some research online, you’ll see lots of ideas for DIY seed-starting set-ups – everything from using old egg cartons to making biodegradable newspaper seed pots that can be planted in the ground come spring.

Depending on your budget, reusing household containers and relying on natural sunlight may be your best (and least expensive) option for starting seeds indoors. But if you’re looking to start seeds indoors without having to rely on natural light, then creating a DIY seed-starting system is typically more cost-effective than buying a pre-made one.

And remember, while the seed starting supplies shared in this post are an investment, they can also be used year after year!

Can you start seeds in regular potting soil?

If you only have access to regular potting soil, you can absolutely use it to start seeds. However, potting soil can be heavier and coarser than soil meant for starting seeds, so it can be harder on new seedlings. If possible, I recommend using a seed-starting soil mix or vermiculite.

What month is best to start seeds indoors?

Many plants – flowers and vegetables – can be started indoors in mid-March to prepare for the spring growing season. However, it’s important to pick your planting dates based on each individual plant and its growing time.

I share more about how to plan for seed starting in the next post in this series, sharing tips to get organized before starting seeds.

CLICK HERE to get my FREE DOWNLOADABLE PRINTABLE that will help you get organized to sow seeds this year. Print as many pages as you want and add to your gardening journal for ease of reference during the growing season.

DIY Seed Starting System Wrap-Up

Have you ever started seeds indoors before? What supplies did you use or would recommend? I would love to know more in the comments below.

And don’t miss joining my Gardening DIY and Decorating Community on Facebook for more chatter. And follow along there and on Instagram as well. There are behind the scenes daily things that I share on Instagram that don’t make it on the blog. Would love to see you there too!

If you prefer to binge watch Bricks ’n Blooms on TV, we go more in-depth with tours and posts on my YouTube channel. Would love to hang out with you there!

Thanks for stopping by the blog today!

Enjoy your day! xoxo