How to Start Seeds Indoors Without a Greenhouse

Learn how to start seeds indoors without a greenhouse! Step-by-step guide, tips for success, and essential equipment.

If you’ve never started a garden from seed before, you’re in for a treat! It’s truly amazing how a tiny seed can transform into something beautiful or edible. I’ve been starting seeds indoors for years, and I’m excited to share my best tips for success – no greenhouse required.

Whether you dream of vibrant flowers, fragrant herbs, or delicious vegetables, this guide will equip you with everything you need to know to start seeds indoors and nurture them into thriving plants.

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Why Sow Indoors?

Starting seeds indoors offers a wealth of benefits:

• Control: You have the power over light, temperature, and moisture.
• Head Start: Get a jump on the growing season and enjoy earlier blooms and harvests.
• Protection: Shield your tender seedlings from harsh weather and pests.
• Variety: Explore rare and unique plants not readily available at nurseries.
• Budget-Friendly: Grow more plants for less money.
• Rewarding: Experience the satisfaction of nurturing plants from the very beginning.
• Winter Activity: Starting seeds indoors helps beat the winter blahs.

Dispelling the Greenhouse Myth

I used to believe that a greenhouse was essential for successful seed starting. But I was wrong! You absolutely do not need a greenhouse, but you do need the right equipment.

For years, I struggled to start seeds in front of my south-facing windows. Space was limited, the light was inadequate, and my seedlings were often leggy and weak. Then, I made a crucial mindset shift and invested in proper grow lights.

The results were transformative! I moved my seed starting operation to my basement (and later, my sunroom) and successfully started over 1400 flowers! It was incredible, and I was amazed at how much easier and more effective grow lights made the process. I still do not have a greenhouse and have started thousands of seeds without one for several years.

Creating Your Indoor Seed Starting Station

Location is Key

Find a spot in your home with these qualities:

• Space: Enough room for your seed starting setup and growing seedlings.
• Light: Limited natural light is okay, as you’ll be using grow lights.
• Accessibility: A place where you can easily tend to your seedlings.

Essential Equipment

Here’s what you’ll need:

• Seeds: High-quality seeds from reputable sources.
• Vermiculite: To improve drainage and aeration in your seed starting mix.
• Seed Starting Potting Soil: A lightweight mix specifically formulated for seedlings.
• Seed Trays: Choose trays with drainage holes and consider cell trays for individual seedlings.
• Bottom or Drainage Trays: To catch excess water and prevent messes.
• Clear Dome Lids: To create a humid environment for germination.
• Grow Lights: Essential for strong, healthy seedlings. Invest in full-spectrum LED or fluorescent grow lights.
• Table or Shelf System for Seedlings: To hold your seed trays and grow lights.
• Heat Mat: Optional, but helpful for seeds that require warmer temperatures to germinate.
• Plant Labels: To keep track of your varieties.
• Oscillating Fan: To improve air circulation and prevent damping-off.
• Programmable Timer: To automate your grow light schedule.

DIY Seed Starting Systems

While pre-made tiered systems are available, they can be expensive. My husband and I created our own DIY system using wire shelves and four-foot grow lights. It’s been incredibly effective and much more budget-friendly.

Get creative with your setup! Repurpose old bookshelves, build your own shelves, or even use sturdy cardboard boxes. The key is to have a stable structure to support your grow lights and seed trays.

Pro-Tip: When reusing seed starting supplies, it is essential to clean them really well with a 1:10 ratio of chlorine bleach to the water to sanitize and kill any pests or diseases lingering behind. This is actually a good practice for any pots or containers that you re-use for any type of plant.

Choosing and Sowing Your Seeds

Seed Selection

Invest in high-quality seeds from reputable sources. My favorites include:

• Floret Flower Farm
• Johnny’s Select Seeds
• Renee’s Garden

Shop early (December and January) for the best selection. You’ll still find seeds online after December and January, but there may not be as many options or varieties to choose from. Keep in mind, that some flowers and vegetables might need to be sowed sooner than later, so you will want to get your seeds early.

When to Start Seeds Indoors

Determine your “last frost date” and use seed packet information to create a planting schedule. Count backward from your last frost date to determine when to start each variety.

In New Jersey, my last frost date is typically around or just after Mother’s Day, but in the last few years, it’s been stretched to mid-May. I still tend to plant tenders around Mother’s Day anyway, but watch the weather like a hawk and am prepared to cover anything that is susceptible to frost.

With the last frost date in hand, look through each seed packet. Write down the flower, variety, date of maturity, when it should be sowed, seed starting dates, overall size, and color. The best way to keep track of it all is in a garden planner like this one, but you can easily create a spreadsheet on your computer too.

Not only does this make planning the garden easier, but it helps hone my seed starting supply list too. And you can even add a notes column so you can jot down any growing notes of what you learned during the season. Like did this variety need staking? Was it more susceptible to a resident rabbit? Did it germinate with ease?

Want To Get More Organized to Start 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 them to your gardening journal for ease of reference during the growing season.

Sowing Techniques

1. Fill your seed trays or pots with pre-moistened seed starting mix. Gently pack it down to remove air pockets.
2. Sow seeds according to the packet directions, planting them at the correct depth.
3. Cover the seeds with vermiculite or seed starting mix.
4. Label your trays or pots.
5. Cover the trays with clear dome lids.
6. Place the trays on a heat mat (if using) under your grow lights.

Tips for Success

Here are some common seed-starting challenges and how to overcome them:

• Poor Germination: Ensure proper temperature, moisture, planting depth, and light. Use fresh, high-quality seeds.
• Leggy Seedlings: Provide adequate light and consider using an oscillating fan to strengthen stems.
• Damping Off: Prevent this fungal disease by using sterile seed starting mix, avoiding overwatering, and ensuring good air circulation.
• Inconsistent Growth: Start with a quality seed-starting mix and monitor temperature and moisture levels closely.

Hardening Off: The Final Step

Before transplanting your seedlings outdoors, it’s crucial to “harden them off.” This process gradually acclimates them to outdoor conditions, preventing shock and ensuring their survival.

About two weeks before your last frost date, start by placing your seedlings in a protected, shady location for a few hours each day. Gradually increase their exposure to sunlight and wind over the next week or two. To learn more about how to properly harden off your seedlings, head over to my detailed post here.

From Seed to Garden

Starting seeds indoors is a rewarding journey that connects you to the magic of nature. With the right knowledge and equipment, you can create a thriving indoor garden and enjoy the fruits (and flowers!) of your labor.

Flowers I Start From Seed Indoors Every Year

While I love to try new things every growing season, there are a few tried and true blooms that I grow year after year from seed indoors. Here is my list:

• Zinnias
• Strawflowers
• Ageratum
• Celosia
• Gomphrena
• Statice
• Amaranth

I grow lots of other flowers from seed too, but I grow them using the winter sowing method (sowing seeds outdoors in winter) and direct sowing seeds in spring.

Herbs and Vegetables I Grow From Seed

Since I focus more on starting flowers from seed, I don’t do as much herbs and vegetables consistently. But here’s a list of plants I’ve started from seed with success:

• Basil
• Parsley
• Cilantro
• Tomatoes
• Bell Peppers

More About Starting Seeds Indoors

What kind of garden do you want to grow from seed? Have you ever started seeds indoors before? I would love to know more in the comments below.

For more information about starting seeds indoors, please check out this article from the Rutgers Cooperative Extension.

To follow along with the rest of this Grow With Me series, please check out these posts.

• An Overview (you are here)
• Supplies for Starting Seeds Indoors Without a Greenhouse
• 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

Thank you for visiting the blog today!

Enjoy your day! xo