Starting Tomatoes Indoors: A Beginner’s Guide

Starting tomato plants indoors is the only way to get a head start when you have a shorter growing season like ours. Here are the steps you need to take to start tomato plants indoors:

Choose Your Tomato Variety

Choose the tomato variety you want to grow. There are many different types of tomatoes, each with its unique characteristics. Some popular varieties include:

  • Cherry tomatoes
  • Roma tomatoes (Paste; Determinant – produce one large crop at the same time)
  • Pollock tomatoes (Slicing; Indeterminant – produce all season continuously.)



For more detailed information on starting and growing tomatoes visit:

March is time to start those tomato plants…


How to Grow and Care for Tomatoes: A Gardening Guide

Gather Your Supplies

To start tomato plants indoors, you will need the following supplies:

  • Seed starting trays or pots.
  • Seed-starting soil mix
  • Tomato seeds
  • Grow lights or a sunny window.
  • Watering can or spray bottle.

For seed-starting pots, I highly recommend using non-woven nursery pots. I use the 16Fill with 1/3 or 1/2 soil, then plant the seed. As the plant grows, I clip leaves and bury the plant to form new roots for the whole height of the bag. This makes for an amazingly robust root system.

Here is a link to the nursery pots on Amazon!

Start Your Seeds

Start your seeds 6-8 weeks before your last expected frost date. Follow these steps to start your seeds: TIP: Use deep pots/containers. 

  1. Fill your pots with an inch or two of soil.
  2. Moisten the soil with water.
  3. Plant 2-3 seeds per pot, about 1/4 inch deep.
  4. Cover the pots with plastic wrap or a humidity dome to create a greenhouse-like environment. A seedling heat mat works well for tomatoes.
  5. Place the pots under grow lights or in a sunny window. Tomato seeds need at least 6-8 hours of sunlight a day.
  6. Keep the soil moist but not waterlogged. Use a spray bottle. Seeds only need to be moist.
  7. After the seeds have sprouted, remove the plastic wrap or humidity dome. After the seeds have sprouted, start watering your plants from the bottom to reduce dampening off. 
  8. Once the seedlings have grown to about 2 inches tall, thin them to one plant per pot.
  9. As the plants grow, cut the bottom leaves off and add soil around the plant. Tomato plants will shoot out more roots as they become buried.
  10. Continue burying the plant as it grows up and above its pot. If the plant gets too big for its pot, replant. 

Transplant Your Seedlings

Once your seedlings have grown to be about 6-8 inches tall and have developed their first true leaves, they are ready to be transplanted outside. Here are the steps to transplant your seedlings:

  1. Choose a location in your garden that receives at least 6-8 hours of sunlight a day.
  2. Prepare the soil by adding compost or fertilizer.
  3. Dig a hole for each seedling, making sure it is deep enough to cover the root ball.
  4. Gently remove the seedling from its pot and place it in the hole.
  5. Fill in the hole with soil and gently firm the soil around the base of the plant.
  6. Water the seedlings well.

I Grow my tomatoes in Grow Bags. 7 Gallon or 10 Gallon work great for a single plant. As with the nursery pots I will transplant the tomatoes right top the bottom of the bag and bury the stem as it grows. 

Here is a link to Some of the Grow Bags I use on Amazon!

Care for Your Tomato Plants

To ensure your tomato plants thrive, there are a few things you need to do:

  • Water your tomato plants regularly. Tomato plants need about 1-2 inches of water per week.
  • Fertilize your tomato plants every 2-3 weeks with a balanced fertilizer.
  • Stake or cage your tomato plants to keep them upright and off the ground.
  • Monitor your plants for pests and diseases, and treat them promptly if you notice any issues.

With these simple steps, you can successfully start tomato plants indoors and transplant them outside for a bountiful harvest.

Recommended reading

For more detailed information on starting and growing tomatoes, visit:

March is time to start those tomato plants…


How to Grow and Care for Tomatoes: A Gardening Guide

Seeds and planting
Links and Resources

Recommended Products
(These are some of what I use)

These nursery bags
These Grow bags

Pages Seeds Page
Get a Head Start on Spring: The Benefits of Starting Your Seeds Indoors
Saving Vegetable Seeds: A Comprehensive Guide to Gardening Success Planting Guide
Pollock Tomatoes (North hardy Tomato variety)
Tomatoes (Useful information on starting tomatoes from seed)

DIY Garden Irrigation System: A Detailed Guide for Northwest Ontario

Blog Posts

When to start planting seeds
Germination testing your seeds
Looking for sources for seeds?
Heirloom seeds
Chitting your way to more potatoes
So it's before the first frost; what can I plant?


Individual seed and plant information is available in the  "Gardening Shortcut Links" above under "North Hardy Plants to grow". I have successfully grown all of these, and most I grow year to year.







myBackyard is for recreational purposes only. Plants, mushrooms and berries cannot be 100% identified through this website alone. It is up to the reader to properly identify plants, fungi and trees. Some wild plants, berries and mushrooms are poisonous or can have serious adverse health effects. Even those listed as edible may cause adverse reactions in individuals. participates in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to,, and affiliated sites. As an Amazon Associate, we earn from qualifying purchases through our links.

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