Starting Seeds Indoors: Best Practices for Organic Gardeners

You know that moment when you’re elbow-deep in a bag of potting mix, and you catch yourself smiling for no reason? That’s not just gardening joy; there’s actual science behind it. A study shows that a type of bacteria in soil, Mycobacterium vaccae, triggers serotonin production, making you happier and more relaxed. Who needs a spa day when you’ve got seed trays?

I’ve been growing plants indoors for years, and let me tell you, once you get the hang of it, you might find yourself with hundreds of seedlings. I used to grow so many plants every spring that I’d sell extras to cover my gardening costs. Because honestly, it’s not much harder to grow a hundred seedlings than it is to grow a few. Go big or grow home, right?

Why Start Seeds Indoors?

Starting seeds indoors gives you a head start on the growing season, especially for crops that need a longer time to mature, like tomatoes, peppers, and eggplants. Plus, it’s way cheaper than buying seedlings at the garden center. You’re also in control of what varieties you grow and what goes into your plants: organic seeds, organic potting mix, and no mystery chemicals.

And let’s be honest, there’s something magical about seeing those tiny green shoots pop up and knowing you started them from scratch. It’s like being a plant parent, minus the tantrums.

What You’ll Need to Get Started

Before diving in, let’s talk about timing. For northern New Jersey, February is the perfect time to start seeds indoors for crops like lettuces, broccoli, kale, cabbage, eggplants, bell peppers, and tomatoes. Starting these crops now ensures they’re ready to thrive when the weather warms up.

Don’t worry, you don’t need a fancy setup to grow seeds indoors. Here’s what I use:

• Seed trays or containers: Reuse old yogurt cups or purchase seed trays. Just make sure they have drainage holes. The seeds don't need a lot of soil at this stage and I use large capacity trays like these 128 cell seed starter trays.
• Organic potting mix: Avoid garden soil; it’s too heavy and can introduce pests.
• Light source: If you’ve got a sunny windowsill, great. If not, check out my post on using LED lights to grow seeds indoors (Can You Use LED Lights to Start Seeds?). LEDs are affordable, energy-efficient, and work like a charm.
• Seeds: Choose organic seeds that are suited to your climate. Starting with veggies you love to eat is always a good idea.
• Labels: Trust me, you won’t remember which tray is which by day three. I use a silver Sharpie to label the rows (A-H) and columns (1-16) and keep track of what I'm planting with a spreadsheet. When I transplant them in larger pots I print out custom plant labels on waterproof paper.

The Steps to Seed-Starting Success

1. Plan Your Crops: Start seeds indoors now for crops like broccoli, kale, cabbage, eggplants, bell peppers, and tomatoes. These crops require a longer growing season, and starting them indoors gives you a jumpstart before outdoor planting.
2. Fill your seed starting trays with organic seed starting mix: It should feel light and fluffy. Fill the trays and give them a few taps to settle but don't pack them in, top off with more potting mix.
3. Plant Your Seeds: Follow the depth instructions on the seed packet. Rule of thumb: plant seeds twice as deep as they are wide. I use a tooth pick to make the holes and cover them back up. 
4. Water Gently: I place the trays in a tray of water to soak up moisture, cover with humidity dome. The potting mix should have fertilizer and beneficial microbes but I've gotten in the habit of spraying a bit of diluted Espoma Grow on the top because I know it has bacillus subtilis and I never had any issues with damping off. 
5. Keep Them Warm: Most seeds germinate well around 65–75°F. If your home is chilly, a seedling heat mat with thermostat helps a lot.
6. Be Patient: Some seeds, like peppers, take longer to sprout. Keep the soil moist but not soggy, and resist the urge to overwater.
7. Provide Light: Once the little green babies start poking out of the potting mix, place your trays in a sunny spot or under LED lights. Position lights a few inches above the seedlings and adjust as they grow. They may not all come up at the same time so I might remove the humidity dome and cover ungerminated cells with plastic wrap until they start coming up. It's important to group your seeds by germination time.

It's Not Hard Growing Hundreds of Tomatoes

For a few years, I got overly ambitious and started about 300 plants. I had plenty for my and my relatives gardens and was able to sell enough online to cover my gardening costs.

Pro Tips for Better Seedlings

• Airflow Matters: Use a small fan to keep air circulating around your seedlings. It prevents mold and helps plants grow strong stems once they emerge from the soil. In fact get a clean dowel and brush them with them from time to time to make them even stronger.
• Feed Them: Once your seedlings develop their first true leaves, start feeding them with a diluted organic fertilizer.
• Transplanting: When seedlings outgrow their containers, gently move them to larger pots. Handle them by their leaves, not stems. I like to use larger trays like these 18 planting pot cells.

Why It’s All Worth It

Not only does starting seeds indoors save money and give you healthier plants, but it also brings a little extra joy into your life. There’s something therapeutic about watching your plants grow day by day. And let’s not forget the bragging rights. When your neighbors ask where you got those gorgeous tomatoes, you can casually say, “Oh, I grew them from seed.”

Ready to dig in? Grab your potting mix and seeds, and let’s get growing. If you’re looking for more tips, check out my post on how to build your own compost bin to create nutrient-rich soil for future gardening projects. You’ve got this.