Starting Seeds Indoors vs Direct Seeding Outdoors

Seed starting, transplanting, and direct seeding – you’ve probably heard of these terms before, but if you’re not sure what they mean, read on!

Many plants can be sown directly (i.e., direct seeded) into the garden. However, some slow-growing plants need a head-start before being planted outdoors, which means starting the seeds indoors and then transplanting the seedling into the garden once the weather’s ideal. Starting seeds indoors is also beneficial when you’re trying to squeeze in multiple types of vegetables in the same garden plot one after the other (read more about succession planting here).

So, how do you know which seeds to start indoors and which to direct seed outdoors?

As a general rule of thumb, plants should be started indoors and then transplanted later if all of the following apply:

  • the vegetable has a long days-to-maturity, usually greater than 90 days;
  • the plants cannot withstand one of frost or heat; AND
  • the plants do not have taproots – these plants generally do not like transplanting.

In Canada, heat-loving plants such as tomatoes, peppers, and eggplants must be started indoors and transplanted to achieve a full harvest. This is because the length of their full growth cycle exceeds the length of our summer.

Other plants, such as broccoli, cabbage and cauliflower, are much more likely to succeed when started indoors. These vegetables must be in and out of the garden between the winter freeze and the summer heat as they cannot withstand either. This only allows for a small window of time, which is best achieved by starting them indoors and then planting semi-mature seedlings outdoors to speed up the maturation process.

Starting seeds indoors for vegetables such as lettuce, kale, chard, and most herbs is optional. They’ll thrive when direct seeded, but you can speed up their production in your garden by starting them indoors and then transplanting semi-mature plants into the garden.

Now that you know which of your veggies to direct seed outdoors and which to start indoors, we’ve created two mini-guides to share tips on how to do both:

As always, feel free to reach out if you have any questions!