
How to Grow Tomatoes from Seed
Cultivating tomatoes from seed is a rewarding way to enjoy a wider variety of flavors than those found in stores. This guide walks you through the process of starting your seeds indoors to ensure a healthy harvest once the weather warms up.

Prepare the seed tray
10 minutesFill your seed starting tray with moist, sterile seed starting mix, leaving about half an inch of space at the top.
Using a sterile mix prevents damping-off, a fungal disease that kills young seedlings. Ensure the mix is damp but not soaking wet before planting.
Pre-moisten the soil in a bucket before putting it into the tray to ensure even hydration.

Plant the tomato seeds
10 minutesPlace two tomato seeds into the center of each cell and cover them lightly with about 1/4 inch of soil.
Planting two seeds increases the chance of germination; you can thin out the weaker one later if both sprout. Gently press down on the soil surface to ensure good seed-to-soil contact.
Label your tray with the tomato variety and date to keep track of growth progress.

Mist and cover the tray
5 minutesMist the surface of the soil with water and cover the tray with a humidity dome or plastic wrap.
The cover creates a mini-greenhouse effect, trapping heat and moisture which are essential for germination. Keep the tray in a warm location, ideally between 70-80°F.
Place the tray on top of a refrigerator or a dedicated heat mat to speed up the process.

Monitor for germination
2 minutes dailyCheck the tray daily for signs of green sprouts and remove the humidity cover as soon as they emerge.
Tomato seeds typically germinate in 7 to 14 days. Once you see the first loops of green, the seedlings need airflow to prevent mold and to begin growing strong stems.
Do not let the soil dry out completely, as this will kill the fragile emerging roots.
Check the soil moisture daily; it should feel like a wrung-out sponge.

Provide adequate light
OngoingPlace the seedlings under grow lights or in the sunniest south-facing window available.
Seedlings need 12-16 hours of light per day. If using grow lights, keep them 2-3 inches above the tops of the plants to prevent the seedlings from becoming 'leggy' or stretched.
Leggy seedlings are weak and prone to falling over; increase light intensity if you notice this.
Rotate the tray daily if growing in a window to ensure the plants grow straight.
Pro Tips
- ●Start your seeds 6-8 weeks before the last expected frost date in your area.
- ●Brush your hands over the seedlings daily to simulate wind, which strengthens the stems.
- ●Use a fan on low speed nearby to increase air circulation and prevent fungal issues.
- ●Only fertilize with a weak liquid fertilizer once the first set of 'true leaves' appears.