When to Start Planting Seeds

When can you plant seeds? This is a common question for gardeners!

You can figure out when to plant seeds by knowing your spring frost dates and sow the seeds accordingly.

Once you know your frost dates which we’ll discuss in this post, you can count back the weeks for when you sow your seeds or transplant your seedlings into the garden. If you need help with seed starting be sure to read my seed starting 101 beginner guide.

It all starts with the seed.

Watching it germinate, watching it grow, and watching that plant become a wonderful harvest. Gardening is amazing!

It’s always good to double check your seed packet though, as each variety will be different. Also keep in mind seed age, quality (if they were stored properly) and vigor will all change how long it takes for your seeds to sprout and grow.

First you will need to know your frost dates.

when to sow or transplant your seeds

When to Plant Seeds

Once you know your frost dates keep them in mind and count back the weeks to that date.

Your frost date is an approximate time frame of when you can sow your seeds.

Every gardening season will be different, some years the frosts end or come sooner than others. I also often gamble my frost dates with cool season crops because some crops can handle frosts.

When to plant your seeds indoors or outside

Cool Season Crops to Direct Seed Before Last Frost:

  • 6-8 weeks: arugula, mache, spinach
  • 4-6 weeks:  peas, radishes, claytonia,
  • 3-5 weeks: lettuce, green onions/scallions, radishes, swiss chard, turnips,
  • 3-4 weeks: broccoli, broccoli raab, cabbage, brussel sprouts, collards, kale, mizuna, mustards, bok/pak choi,
  • 2-4 weeks: carrots, mibuna, parsnips, plant potatoes, tatsoi
  • 1-2 weeks: endive, rutabagas

Cool Season Crops to Direct Seed with Season Extenders

These cool season crops are direct seeded with cold frames, hoop tunnels, greenhouse, etc.

  • 8-10 weeks: arugula, cabbage, carrots, lettuce, mache, green onions/scallions, spinach, swiss chard,
  • 6-8 weeks: broccoli, claytonia, collards, endive, kale, kohl rabi, mizuna, mustards, bok/pak choi, radishes, tatsoi, turnips
  • 4-6 weeks: any of the above veggies.
  • 2-4 weeks: cauliflower (needs frost protection, there’s the odd variety that can handle cold temps).

Direct Seed After Last frost

These are your warm season crops.

1 week after: Beans, corn.

when to sow or transplant your seeds

When should you start growing your Transplants?

  • 10-12 weeks before last frost: Leeks, onions, celery, celeriac, perennial herbs like oregano, savory, thyme…
  • 6-8 weeks: Tomatoes, peppers, eggplant, Brassicas (cabbage, cauliflower, broccoli, kale, kohl rabi etc)
  • 4-5 weeks: Basil, watermelons/melons
  • 2-3 weeks: Summer and winter squash, cucumbers
  • 1 week before: Sweet corn
  • 1-2 weeks after: fall brassicas going into the ground in June
  • 2+weeks: if you plant a fall /winter garden back date from time you need to be transplanting.

When is it safe to Transplant?

  • 4-5 weeks before last frost: onion transplants
  • 3-4 weeks before last frost: broccoli, leeks, lettuce, mustards
  • 2-3 weeks before last frost: cauliflower (needs protection), celery, celeriac, kale, kohl rabi, bok/pak choi
  • 1- 2 weeks before last frost: cucumbers*, melons*, peppers*, zucchini*, tomatoes*
  • (*this is risky so you definitely NEED frost protection. Eg. Greenhouse, polytunnel, frost fabric..)

Plants to Transplant 1 Week After Last Frost

Eggplant, peppers, tomatoes, melons, peppers, zucchini/summer squash, sweet potatoes, and winter squash.


when to start seeds? Count back from your spring frost dates to learn when to sow in any climate


2 thoughts on “When to Start Planting Seeds”

  1. Thank you for this. I am an experienced zone 8b gardener, but only a beginner in zone 5b. Wowzers is my learning curve ever steep! So many more restrictions to deal with. I’m close to the Canadian border at about 1500 ft. Sounds like you may be in a similar gardening zone
    I noticed that you nentioned fava beans (I was quite happy about that as not many grow them). Here in zone 8b I plant them either in February or in the fall.
    When do you plant them in zone 5?
    Thank you again for this article, and here’s hoping you see this comment/ question 🙂


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