Jumpstart Your Garden: Why & How to Start Seeds Indoors

Let’s be honest—Canadian winters in Georgina's growing zone 5 don’t exactly scream “plant your garden now!” But while the snow piles up outside, you can get a jump on the growing season by starting seeds indoors. It’s like giving your plants a VIP pass to an early start, ensuring they’re strong, healthy, and ready to hit the ground running (or growing) when spring finally shows up.

 

Why Start Seeds Indoors?

There are plenty of reasons to start seeds indoors rather than waiting for warm weather to sow them outside:

• Longer Growing Season – Some plants need more time to mature than our short summers allow. Starting indoors ensures they get a full growing cycle.
• Stronger, Healthier Plants – Seedlings grown inside are protected from harsh weather, surprise frosts, and hungry critters.
• Cost Savings – Buying seed packets is far cheaper than purchasing pre-grown seedlings.
• More Variety – You can grow unique and heirloom varieties that you won’t find at your local garden centre.

What You’ll Need to Start Seeds Indoors

Starting seeds is easy when you have the right setup. Here’s what you’ll need:

• Seeds – Choose your veggies, herbs, and flowers wisely (more on that later).
• Seed Trays or Containers – Anything from egg cartons to fancy seed trays will work. Just make sure they have drainage holes!
• Seed-Starting Mix – A light, well-draining mix is best. Avoid regular garden soil; it’s too heavy and can harbour diseases. 
• Water & Humidity – Keep the soil moist but not soggy. A humidity dome (or plastic wrap) can help keep moisture levels up.
• Grow Lights – A sunny windowsill *might* work, but grow lights ensure strong, healthy seedlings. Aim for 12–16 hours of light daily.
• Warmth – Seeds need consistent warmth to germinate. A heat mat can help speed up the process.
• Labels – Trust me, you won’t remember what you planted where. Label everything!

 

When to Start Seeds Indoors

Timing is everything! Most seed packets will tell you when to start seeds based on your last frost date (which, in Georgina's zone 5, is usually around mid-to-late May/early June). Here’s a general guide: 

8–12 weeks before the last frost (Late February–March)

• Slow-growing plants like peppers, celery, onions, and perennial flowers. 

6–8 weeks before the last frost (March–April)

• Common veggies like tomatoes, eggplants, broccoli, and cauliflower.
• Many herbs like basil, oregano, and thyme.
• Annual flowers such as snapdragons and petunias. 

4–6 weeks before the last frost (April–Early May)

• Faster-growing veggies like cucumbers, squash, and melons (if you must start them inside).
• More herbs like parsley and dill.
• Flowers like zinnias and marigolds.

What Vegetable Seeds to Start Indoors

Not all veggies need to be started inside—some prefer direct sowing in the garden. But these ones love a head start:

Broccoli & Cauliflower – These cool-season crops need extra time to mature.

Tomatoes & Peppers – The MVPs of indoor seed starting.

Eggplants – Need warmth and a long season to thrive.

Celery – A slow grower that benefits from an early start.

Lettuce & Greens – While they can be direct-seeded, early indoor starts give you an extra-early harvest.

 

What Herb Seeds to Start Indoors

Herbs can take their sweet time to grow, so starting them inside gives them a fighting chance:

Basil – Loves warmth, so give it a cozy indoor start.

Oregano, Thyme & Rosemary – Slow growers that need extra time.

Parsley & Dill – Can be slow to germinate, so starting early is key.

Chives – Hardy, but an early start helps them establish quickly.

What Flower Seeds to Start Indoors

Want an early burst of colour in your garden? Start these flowers inside:

Petunias & Snapdragons – Long bloomers that need extra growing time.

Marigolds & Zinnias – Faster-growing flowers that thrive indoors first.

Lavender & Echinacea – Perennial beauties that take their time to establish.

Morning Glories & Nasturtiums – While they can be direct-seeded, starting them inside gets them blooming faster.

 

How to Start Seeds Indoors

1. Fill Containers with Seed-Starting Mix: Moisten the mix slightly before planting.
2. Plant Seeds at the Right Depth: Seed packets provide specific depth instructions.
3. Label Your Seeds: Avoid mix-ups by using plant markers.
4. Cover for Humidity: Use a plastic dome or plastic wrap to keep moisture in.
5. Provide Light: Place under grow lights or near a sunny window (south-facing is best).
6. Keep Moist but Not Soggy: Use a spray bottle or gentle watering method to keep the soil damp.
7. Maintain Proper Temperature: Most seeds germinate best at 18-24°C (65-75°F). A heat mat can help with warmth-loving plants like tomatoes and peppers.
8. Harden Off Before Transplanting: About a week before moving outdoors, slowly introduce seedlings to outdoor conditions by placing them outside for a few hours each day, gradually increasing the time.

So there you have it, starting seeds indoors is one of the best ways to maximize Georgina's growing season. With a little planning, the right setup, and some patience, you’ll have a garden full of strong, healthy plants ready to flourish as soon as the weather allows. Now, grab those seed packets, set up your grow lights, and let’s get growing.

Happy gardening!

 

Shannon, the Garden Girl

Shannon, the Garden Girl, shares which vegetable, flower, and herb seeds should be started indoors and which ones are better to direct sow outside when the weather warms up.