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University of Minnesota Extension

It's time to start your seeds

Spring is just around the corner and now is the time to start seeds indoors, especially if you want a specific kind of tomato, pepper or impatiens flowers for your garden. Some seeds grow slowly and others are quite rapid to germinate.

How do you know when to start which kind of seed?

Here are some tips for new and experienced gardeners:

  • Read the information on the seed packet for when to start the seed indoors. If the packet says sow directly outdoors and gives no info on starting seed indoors, those seeds grow quickly outdoors and likely do not need a head start indoors.
  • Minnesota’s spring last frost date typically happens between May 10 and 31, depending on where you live.
    • Weather records from 1991 through 2010 show a 10 percent probability of 32°F as of May 10 in the Twin Cities.
    • The last frost date is a guideline for moving your seedlings outdoors.

Suggested starting dates for popular vegetables and flowers:

Two bees on white flowers of spicy globe Greek basil (Ocimum basilicum 'Minimum') with pink and purple petunias in the background.

Late February or early March:  

  • Impatiens 
  • Petunias 
  • Leeks
  • Onions

Early to mid-March: 

  • Cabbage
  • Broccoli
  • Cauliflower


  • Eggplant
  • Okra
  • Peppers

Early April: 

  • Tomatoes
  • Kale
  • Leaf lettuce

Mid to late April:

  • Squash
  • Melons
  • Cucumbers

Leeks, onions, cabbage, broccoli, cauliflower, kale and leaf lettuce can be planted out before the last frost date because, unlike the other crops listed above, these cool season vegetables can tolerate cooler soils and temperatures.


Johnny's Seed Starting Calculator allows you to enter your frost-free date and, with a click of a button, will calculate the starting date for a long list of flowers and vegetable seed. When to sow the seed, and when to move plants outside is customized based on the frost date entered.

Check out Starting seeds indoors for more complete information on light, containers, soil and temperatures for seed starting. 

Happy planting!

Mary H. Meyer, Extension horticulturist and professor

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