Learn to start seeds indoors with this DIY system! Get your seedlings off to a strong start with these 11 essential supplies.
Starting your own seeds indoors is incredibly rewarding, but those pre-made seed starting kits can put a serious dent in your gardening budget. The good news? You can create a DIY seed starting system that’s just as effective (if not more so!) for a fraction of the cost.
In this guide, I’ll walk you through the 11 essential supplies you need to get your seedlings off to a strong start without breaking the bank. I use this set-up every year, every season, to create a gorgeous cut flower garden filled with beautiful blooms. So let’s embrace the power of DIY and make this one ourselves!
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11 Must-Have Indoor Seed Starting Supplies
Let’s get your DIY seed starting system up and running! Below are the 11 essential supplies you’ll need to gather. I’ll share details about my own setup later, but first, let’s cover the basics…
- Seeds: This might seem obvious, but high-quality seeds are the foundation of your success! Choose varieties suited to your climate and gardening goals. (Link to reputable seed sources like the ones you mentioned)
- Vermiculite: While not strictly necessary, vermiculite is a fantastic seed-covering medium. It’s lightweight, helps retain moisture, and allows seedlings to emerge easily.
- Seed Starting Mix: Unlike regular potting mix, seed starting mix is finer and lighter, providing the ideal texture for delicate seedlings.
- Seed Trays: These come in various sizes and configurations. Choose seed trays that fit your space and the number of seedlings you plan to start. I usually go with the 72 or (2) 36 cells.
- Bottom or Drainage Trays: Essential for catching excess water and preventing soggy roots. Look for drainage trays that fit snugly beneath your seed trays.
- Clear Dome Lids: Clear dome lids create a mini-greenhouse effect, maintaining humidity and warmth for optimal germination.
- Grow Lights: Crucial for providing adequate light, especially in areas with limited sunlight. LED grow lights are energy-efficient and provide the right spectrum for seedlings.
- Programmable Timer: Timers help your lighting go on and off daily with a low-maintenance, set-and-forget approach.
- Table or Shelf System for Seedlings: A sturdy surface to hold your trays and lights. You can DIY a system using wire shelves, as I did, or repurpose existing furniture.
- Heat Mat: Heat mats provide gentle bottom heat, which can significantly speed up germination. Not all seeds need additional heat, so read the seed packets for information.
- Plant Labels: Don’t forget to label your trays! You’ll be surprised how quickly you forget what you planted where.
- Oscillating Fan: Oscillating fan improves air circulation, which helps prevent damping-off (a fungal disease that can kill seedlings).
Where to Buy Seeds
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, and Renee’s Garden.
My Indoor DIY Seed Starting System
In my previous home, I started seeds in my basement. Now, I use my sunroom, which is brighter but still requires grow lights for optimal growth. The key is to have adjustable lights that you can raise as your seedlings grow.
Here’s how I created my DIY seed-starting shelf system:
- Grow Lights: I used a combination of 2-foot and 4-foot LED grow lights, piecing them together as needed.
- Why DIY? Pre-made systems were too expensive and lacked the space I needed for my 21 seed trays.
- Choosing the Shelves: We opted for tiered wire chef shelves. They’re affordable, adjustable, sturdy, and can be repurposed for other uses after the seed-starting season.
How to Create a Seed-Starting Shelf System
After much deliberation, 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.
Tips for Choosing DIY Seed Starting Supplies
Do You Need to Use Grow Lights With Your DIY Seed Starting System?
100%!!! When starting seeds indoors, it is essential to use grow lights so you grow stronger, healthier seedlings. To grow well, they’ll need 14-16 hours of light. They just won’t get that during the depths of winter so I strongly recommend investing in lights you’ll use year after year.
You’ll also want the ability to adjust the lights as they need to be within 4 inches of your seedlings to keep them from getting leggy while they grow.
Using Complete Seed-Starting Trays
I have used these complete seed-starting systems and love them. They even have ones with a self-watering tray and peat pot cells. If you can find the ones with the self-watering tray reservoir, get them. It’s much easier to bottom water your seedlings this way.
I’ve even used 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.
Re-Using What You Have With Your DIY Seed Starting System
If you want to reuse containers you already have too, make sure you properly clean them. Use 1 part bleach to 10 parts water and clean everything thoroughly to get rid of any leftover pest or disease issues.
Seed Starting Soil vs. Regular Potting Mix: Why It Matters
You might be tempted to just grab a bag of your usual potting soil and call it a day, but hold on! Seed starting mix is specially formulated to give those tiny seeds the best possible chance at life. Here’s why:
- Texture: Seed starting mix is much finer and lighter than regular potting soil. This allows delicate roots to easily navigate their way through the mix, leading to stronger, healthier seedlings.
- Drainage: Good drainage is essential to prevent soggy soil and “damping off,” a fungal disease that can kill seedlings. Seed starting mix is designed to drain well while still retaining enough moisture for germination.
- Sterility: Seed starting mix is typically sterile, meaning it’s free from weed seeds, diseases, and pests that could harm your seedlings.
- Nutrient Content: While seedlings don’t need a lot of nutrients initially, seed starting mix often contains a balanced blend to support early growth.
Soil quality can make or break any garden, so I can’t stress enough the importance of good quality seed starting mix.
Vermiculite: A Seed-Starting Superstar
Vermiculite is a mineral that expands when heated, creating lightweight, porous particles. It’s a fantastic addition to your seed-starting arsenal for these reasons:
- Moisture Retention: Vermiculite holds onto moisture like a sponge, ensuring your seeds stay consistently hydrated.
- Aeration: The porous nature of vermiculite improves airflow around the seeds, promoting healthy root development.
- Easy Emergence: Seedlings have an easier time pushing through vermiculite than through denser soil.
- Disease Prevention: Vermiculite can help prevent damping-off by improving drainage and reducing soil compaction.
How to use vermiculite:
- Seed Covering: Sprinkle a thin layer of vermiculite over your seeds after sowing.
- Mix it in: Add vermiculite to your seed starting mix to improve its texture and drainage.
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.
Heat Mats for Starting Seeds Indoors
These are the heat maps I use. 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 use. To write on them, I’m just using a Sharpie. Ultimately, you want to use something that won’t rub off too, so keep that in mind with whatever you decide to use.
DIY Seed Starting System: Troubleshooting and Tips
- Damping Off: This fungal disease can be prevented with good air circulation, proper watering practices, and sterile seed starting mix.
- Leggy Seedlings: This is often caused by insufficient light. Ensure your seedlings are close enough to the grow lights.
- Hardening Off: Before transplanting seedlings outdoors, gradually acclimate them to the outdoor environment. Read my article about how to harden off seedlings here.
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!
What month is best to start seeds indoors?
Many plants – flowers and vegetables – can be started indoors in winter to prepare for the spring growing season. Timing depends on your last frost date and when your seedlings need to be started. Some require 10-12 weeks before that last frost date. You’ll want to have your supplies in place and ready to go well before then. 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.
Next up in the series, we’ll be chatting about how to get organized before starting seeds indoors.
For more information about making your own DIY seed starting system, please see this article from the University of Georgia Cooperative Extension.
Thanks for stopping by the blog today!
Enjoy your day! xoxo
How to Start Seeds Indoors Without a Greenhouse Series
- Overview of How to Start Seeds Indoors Without a Greenhouse
- Supplies for Starting Seeds Indoors Without a Greenhouse (you are here)
- 7 Simple Tips to Getting Organized Before Starting Seeds Indoors
- What You Need to Know About Sowing Seeds Indoors
- 7 Lessons I Learned Starting Seeds Indoors
- What You Need to Know About Hardening Off Plants
- How to Plant a Garden After Starting Seeds Indoors
- 7 Lessons I Learned From Growing a Cut Flower Garden
- How to Keep Fresh Flowers Longer
- Cut Flower Gardening for Beginners
