When to Start Seeds Indoors – Planting Chart for Manitoba

Here’s a planting and seed starting chart  specifically for us Zone 3 prairie gardeners.

planting chart
Vegetable Seed Starting Chart – Zone 3. Click for a printable pdf.

This seed starting and planting chart shows when to start veggie seeds indoors and when to plant them outside based on an average first frost free date of May 24. The Farmer’s Almanac has a list of first frost free dates based on data from Environment Canada. Now you know why, in Manitoba, the May Long Weekend is dedicated to putting in the garden!

For a similar chart for herbs check out the Herb Planting Chart.

For details about how to deep and how far apart to plant everything, see the detailed planting chart below.

To create this chart I looked at the seed packages for common veggies for their recommendation on when to start seeds and when to plant outside. Often packages will say something like “start seeds 4-6 weeks before last frost date”. I simply counted backwards 4-6 weeks from May 24. If you don’t see one of your plants in this chart, check the package or online for how many weeks before the last frost date is recommended. Then make a note of it on the chart for future reference.

Of course, these dates are loose recommendations. If you’re on social media or talk to other gardeners you’ll know some people start their seeds much earlier and some start later. The exact date depends on your preference, your set up (lighting in particular), your space and your ability to maintain  growing seedlings effectively. Unless you are experienced and have a great set up I don’t recommend starting seeds to early.

The Danger of Starting Seeds Too Early

Starting seeds is a good feeling and helps alleviate the doldrums of a long winter. But there are consequences of starting too early and it’s not necessarily going to get you bigger or earlier harvests. Unless you have a great set up and know what your doing – read the following carefully.

  1. Plants Become Leggy – Unless you manage your seedlings extremely carefully with just the right amount of light, temperature and food, chances are your plants will grow tall and spindly. They’ll be difficult to manage and may not be sturdy enough to survive the great outdoors.
  2. Plants Become Large & Unmanageable – The larger your seedlings become, the more room they take up and the more difficult they are to manage. You’ll need to transplant them into larger containers before you can transplant them outdoors. Sometimes, you may even need to transplant them a third time. That’s a lot of work and takes up a lot of space. You may even exceed your grow lights, which means your seedlings won’t get optimum light, which means they’ll become leggy!
  3. Plants May Suffer and Become Trickier to Transplant – Large seedlings under grow lights inside a house may start to suffer from lack of nutrients,  natural light and environmental conditions. They may become root bound and as they get bigger transplanting them may create more shock to their system. All of this can be managed, but it takes more knowledge and experience. Bigger is not always better.
  4. Insects and Disease May Become an Issue – You may find aphids, leaf suckers, fungus, viruses or other pests invading your lovely seedlings.
  5. The Urge to Transplant too Soon – If you have large seedlings crowding your inside space, you may be tempted to put them outside before conditions are ideal. Transplanting into soil that is too cool may actually set your transplants back.
herbsunder grow lights
These herbs are growing quickly and need to be transplanted.

Detailed Planting Chart

planting chart for manitoba
Planting Chart for Manitoba, Zone 3. Click to see the full size image.

After repeated years of looking up when to plant what, I finally created my own Planting Chart (to enlarge, right click and open in new tab) based on my experience and the information found on the back of seed packages.

It shows common veggies in our Zone 3 climate.  All I have to do is look up my favourite veggie and I’ll know approximately when and where (indoors or outdoors) to plant it, how many days to maturity and approximately what date it’ll be ready for harvest.  Having a rough estimate of the harvest date is great for planning around extended summer holidays.

If it’s a cold, late planting season, you’d be best off to add a week or two to this planting chart.  It also gives info about spacing, depth, maturity, when to start indoors, and any other special info about a particular plant.

Happy gardening!


  1. Thanks for this information! You saved me a lot of time. Looking forward to using this as a guide this year in Winnipeg.

  2. So glad I found this post!!!
    Your planting chart is helpful for a Winnipeg gardener. I always forget when to start seeds indoors and when to plant outside. I will absolutely be using this.
    Thanks 🙂

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.