When should I plant tomato seeds indoors?

Tomatoes are one of the most popular vegetables to grow in backyard gardens. And while you can start planting the seeds outdoors once the frost has passed, many gardeners prefer to start their tomatoes indoors. This allows them to get a head start on the growing season, extend their harvest time and grow varieties that may not do well in their region. But when is the best time to start planting tomato seeds indoors? Let's take a closer look.

Start with your average last frost date

The best place to start when deciding when to plant your tomato seeds indoors is with your average last frost date. This is the date when it's generally safe to start planting outside without fear of frost damage. You can find out your average last frost date by checking with your local agricultural extension or using an online calculator. Once you have this date, count back 6-8 weeks to determine when you should start sowing your tomato seeds indoors.

Consider your tomato variety

Another factor to consider when deciding when to plant your tomato seeds indoors is the variety of tomato you're growing. Some tomato varieties take longer to mature than others, so you may need to adjust your planting time accordingly. For example, if you're growing a large heirloom variety, you may want to start your seeds indoors earlier than you would for a smaller hybrid variety.

Take into account your growing conditions

The conditions in your home or greenhouse can also play a role in when you should start planting tomato seeds indoors. Tomato seeds require warm temperatures, ideally between 65-75°F, in order to germinate. If your home is particularly chilly, you may need to wait until your indoor space warms up a bit before planting. Additionally, if you live in a particularly dry climate, you may need to supplement with extra water or a humidifier to keep your seedlings healthy.

Additional tips for planting tomato seeds indoors

Once you've determined the best time to start planting your tomato seeds indoors, there are a few additional tips to keep in mind. First, use a high-quality seed starting mix that's specifically designed for starting seeds indoors. This will give your seedlings the best chance for success. Additionally, be sure to properly label your seed trays so you know which tomato variety you're growing.

Keep your seed trays in a sunny location or under artificial grow lights to provide adequate light. Once your seedlings have developed their first true leaves, they can be transplanted into larger containers. Be sure to harden off your seedlings before transplanting them outdoors, so they have time to adjust to outdoor growing conditions.

Starting your tomato seeds indoors is a great way to get a head start on the growing season and extend your harvest time. By taking into account your local last frost date, tomato variety, and growing conditions, you can ensure the success of your seedlings and get a thriving crop of tomatoes come summertime.