You should grow starter tomato plants from seed to be
4-6 inches tall with 4-6 true leaves before transplanting them outside.
Here's why:
* Strong Roots: By this stage, the seedlings have developed a robust root system, which is essential for establishing themselves successfully in the garden.
* Healthy Growth: The seedlings have enough energy stored to handle the shock of transplanting and will quickly adjust to their new environment.
* Hardening Off: It's crucial to gradually acclimate the seedlings to outdoor conditions before transplanting them permanently. This process, called hardening off, helps them withstand sunlight, wind, and temperature fluctuations.
Note:
* The ideal time to transplant tomato seedlings outdoors varies depending on your climate and the specific tomato variety.
* Check your local frost dates and wait until all risk of frost has passed.
* Choose a sunny spot in your garden with well-drained soil.
By following these guidelines, you'll ensure your tomato seedlings have the best chance of thriving in your garden.