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:

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: