Zone 6 Planting: Tips On Starting Seeds For Zone 6 Gardens

Zone 6 Planting: Tips On Starting Seeds For Zone 6 Gardens

The dead of winter is a great time to plan the garden. For example, folks who live in USDA zone 6 have a frost free date range of March 30 – April 30. This means that depending upon the crop, some seeds may be jump-started indoors while others may be suited to direct sowing outside. In the following article, we discuss zone 6 seed starting outdoors as well as starting seeds indoors in zone 6.

When to Start Seeds in Zone 6

As mentioned, zone 6 has a frost free date range of March 30 – April 30 with a more definitive first freeze free date of May 15 and a last freeze free date of October 15. These dates are intended to be a guideline. Different areas of zone 6 may vary by as much as two weeks depending upon the microclimate, but the above dates will give you a gist of when to start seeds in zone 6.

Starting Seeds for Zone 6

Now that you know the frost free range for your zone, it’s time to sort seed packs to decide whether they should be started indoors or out. The direct sow pile will likely include most vegetables such as:

  • Beans
  • Beets
  • Carrots
  • Corn
  • Cucumbers
  • Lettuce
  • Melons
  • Peas
  • Squash

Most annual flowers will also go in the direct sow pile. Those that should be started indoors will include most perennial flowers and any vegetable you want a jump start on such as tomatoes or peppers.

Once you have the two piles, one for indoor sowing and one for outside, begin to read the information on the back of the seed packets. Sometimes the information is scanty, but at the very least it should give you a gist of when to plant, such as “start 6-8 weeks before the last frost date”. Using the last frost free date of May 15, count back in one-week increments. Label the seed packets accordingly with the corresponding sowing date.

If there is no information on the seed pack, a safe bet is to start the seeds inside 6 weeks prior to planting them outdoors. You can then either bind like sowing dates together with rubber bands or if you are feeling particularly orderly, create a sowing schedule either on the computer or on paper.

Starting Seeds Indoors in Zone 6

Even though you have a sowing schedule, there are a couple of things to consider that might change things a bit. For instance, it depends on where you are going to start the seeds indoors. If the only place you have to start seeds is in a cool (under 70 F./21 C.) room, you will want to adjust accordingly and shift to plant a week or two earlier. Also, if you plan on starting seeds in a greenhouse or a very warm room of the house, cut a week or so out of the starting schedule; otherwise, you may find yourself with humongous plants ready to be transplanted before warmer temps arrive.

Examples of seeds to start indoors 10-12 weeks prior to transplanting include leafy greens, hardier varieties of herbs, cool-season veggies, and plants in the onion family. Crops that can be started 8-10 weeks prior to transplanting include many annual or perennial flowers, herbs, and half-hardy vegetables.

Those that can be sowed in March or April for later transplant include tender, heat-loving vegetables and herbs.

Zone 6 Seed Starting Outdoors

As with starting seeds indoors, some concessions may apply when planting seeds outdoors. For instance, if you are going to start the seeds in a cold frame or greenhouse or use row covers, seeds can be sown several weeks prior to the last frost date.

Consult the information on the back of the seed packet regarding when to plant. Count back from the last frost free date and sow the seeds accordingly. You should also check with your local extension office for further information.

Seed Starting: When to Start What?

About this time of year, the itch to start seed starting hits. Those late winter snowstorms send gardeners into their basements to find their lights and flats and double check their stash of seeds to make sure they have all they want. Some gardeners can’t wait even this long, and for them there is winter sowing.

Tomato seedlings thrive under lights.

If you prefer to start seeds indoors, most annuals and vegetables should be started between early March and mid-April in Minnesota. The University of Minnesota Extension service has a fine post about seed starting and recommends that brassicas (cauliflower, broccoli and cabbage) as well as lettuces be started indoors in early to mid-March. (Onions and celery need an even earlier start.) The brassicas are cold-weather crops and generally can be put outdoors earlier and do well in cold frames or hoop houses. A long list of popular annuals, such as petunias, ageratum, coleus and snapdragons, can also be started from seed in early March.

In mid- to late March, plant your peppers and eggplants as well as marigolds, annual phlox, cleome and hollyhocks. These all need eight to 10 weeks indoors under lights before the last frost date.

Hold off until April before doing your seed starting for tomatoes. While some folks plant them earlier, the U recommends waiting. My experience is the seedlings are stronger if they are started later, though I’m sure with enough light and fertilizer you can grow very large plants indoors by giving them more time.

April is also a good time to do seed starting on annuals such as baby’s breath, morning glory, nasturtium, cosmos and zinnias. Some of these annuals can also be sown outdoors after the last frost date for a later bloom.

To learn more about seed starting, check out our articles here, here and here. Or, better yet, take a class from the experts! On March 6, MSHS is hosting a class on seed starting indoors taught by Tom McKusick, publisher of Northern Gardener magazine and a tomato enthusiast, and Marty Bergland, a frequent garden instructor in the Twin Cities.


Laurie Ashworth on February 24, 2019 at 4:26 pm

I am going to start a small garden in my back yard this Spring. I will limit what I plant to cherry tomatoes, spicy lettuce, peppers and a few green beans. I don’t know where to buy small quantities of seeds that are fresh. Could you recommend some websites or stores? I live in White Bear Lake.

Mary Lahr Schier on February 25, 2019 at 1:53 pm

Laurie — Most garden centers should have the seeds (or plants) you need. There is a Bachmans on White Bear Avenue, but any garden center would have lettuce, tomato plants or seeds, etc.. If you prefer to start everything from seed, Seed Savers Exchange is a good mail order company, but I’ve also bought seeds from Burpee, Jung Seeds, Renee’s Seeds and Botanical Interest and had good luck with all of them. Enjoy your new garden!

Terry Roy on March 10, 2020 at 9:51 pm

Laurie, I am in WBL and if you just want a few seeds instead of an entire packet I’d be happy to share. Alternatively, a site called Seeds Now offers small sampler packs of non gmo veg and flower seeds for 1.99 each. The White Bear Library also has a Seed Bank! You can email me terzap (at) gmail com with what you’re looking for, I grow at least 20 different kinds of veg (6 types of beans alone, lol)! I don’t start toms or peppers from seed though.

Mary Lahr Schier on March 11, 2020 at 2:00 pm

Laurie — See Terry’s comment above for ideas. The seed collection at the White Bear Lake Library is a great options. (We’re doing an article on it in Northern Gardener this fall, too.) Most gardeners have extra seeds around to share.

Marilyn Thomas on March 1, 2020 at 11:56 pm

I am new to the area a transplant from the south. I’m helping my daughter with her garden this year (I’ve had many southern gardens) and look forward to any help I can get on growing in this area. Thank you for being here!

Mary Lahr Schier on March 2, 2020 at 12:53 am

Welcome to Minnesota! You may want to check out some of our classes as you get oriented to the area.

Katherine on March 26, 2020 at 5:01 pm

Should I spout my seeds in a damp coffee filter inside a bag or just put them in soil under a grow light?

Mary Lahr Schier on March 31, 2020 at 6:13 pm

Just put them in seed starting mix or potting soil and under the grow light. The only reason to sprout in a coffee filter is if the seeds are somewhat old (ie from a year or two ago) and you aren’t sure if they are still viable. If they germinate in the damp coffee filter, they are viable.

Jonathan Preus on March 30, 2020 at 10:43 pm

I have left over seeds from last year and before. Tomatoes, radishes, beans, lettuce, cauliflower and others. Which of these old seeds are most likely to sprout, which least likely? I will try a few, but would appreciate your advice as to which plants’ seeds stay viable longer. I learned something last year – a small plot where flowers had grown for years proved to be very good for tomatoes, when I moved the flowers and put in tomato seedlings.

I just found your info online by accident, after years living in Lauderdale! Would like to visit your office – open hours?

Mary Lahr Schier on March 31, 2020 at 6:15 pm

Most seeds stay viable for 1 to 3 years. I will put a link below with a veg by veg listing.
Unfortunately, our office is closed due to the pandemic. We are all working from home. Stay safe!

Dee Haataja on April 13, 2020 at 7:25 pm

I am from northern Minnesota, North of Park Rapids. Isn’t a different zone? Thanks Debbie

Mary Lahr Schier on April 13, 2020 at 7:54 pm

Yes, you’re in USDA Hardiness Zone 3. So, it would probably be a good idea to move all the seed starting dates up a couple of weeks. You could plant tomato seeds (indoors under lights) about now to plant out in early June.

Jayne on April 18, 2020 at 7:29 pm

Hello! Twin cities gardener here with a little greenhouse on my deck. Past years I burned my poor plants in it, but I am home to keep an eye on them this spring. :). Anyone recommend starting tomato seeds in the greenhouse mid-April? Will it get too cold at night? You think there’s enough sun light? I am adding better vents in the greenhouse to treive heat if needed, but also worried about that seed starting mix drying out.

Thanks for any advice. I have started marigolds and sunflowers from seed on my kitchen counter under the counter light. They have been repotted and are now cozy in the greenhouse.

Mary Lahr Schier on April 19, 2020 at 3:31 pm

As long as you can monitor the temperature well, you should be fine.

Amy B. Mingo on May 7, 2020 at 3:07 am

I have 2 4×4 raised beds I am prepping with garden soil and compost. I was unable to get seeds until last week so am late to start them. Can I plant directly? I have so many heirloom seeds that came in my order and don’t know if I can plant them all or should save some for starting next year. I have arugula, asparagus, bush beans, beets, broccoli, Brussels sprouts, cabbage, cantaloupe, carrots, cauliflower, celery, corn, pickling cuke, eggplant, honeydew, kale, 4 kinds of lettuce, yellow onion, peas, cayenne, jalapeno, banana and bell peppers, pumpkin, radish, spinach, squash, swiss chard, cherry and beefsteak tomato, turnips, and watermelon. Whew. Any help you can give me would be great. Im 52 but this is my first veggie garden ever. I am able to use cages and trellises for things to climb and be stabilized as well. Thank you so much.

Mary Lahr Schier on May 7, 2020 at 1:07 pm

Wow, that is a lot — especially for a first vegetable garden. I’m not sure how much space you have, but it might be a good idea to focus on the vegetables you like the most this year. Many of the seeds you have can be planted directly, such as arugula, Swiss chard, lettuce—any of the greens—plus melons, beets, cucumbers, radish and squash. Tomatoes, eggplant and peppers are usually started indoors in mid-April, so you are a bit late for those, but you could try. If you are growing onions from seeds, I’d hold those until next year as they take a long time. Asoaragus is a more complicated crop to get started. You may want to research that a bit before planting. Good luck!

Mugdha Halbe on November 17, 2020 at 7:01 pm

Last year some of seeds from my annual flower fell on the ground and they germinated it self, when I saw plants growing, I dug them and put them in the pot and they did well. So it forced me thinking may be I can do the same thing with my other annuals, just put them in the ground now(for 2-3 annuals I already did it), and then they will geminate as nature allows.
Would be ok, if I do that now this week since ground is not really frozen, for some more spring and summer flowers?

Mary Lahr Schier on November 18, 2020 at 4:31 pm

You can sure try it. I’m not sure where you are located. In Minnesota, people often use the winter-sowing method to start perennials, vegetables and annuals outdoors. Here’s some information on that:

[…] for a shorter growing season than do vegetable gardeners in states farther south. You might have to start your seeds inside or consider buying starts once the last frost passes. With a relatively short gardening […]

Joe Vail on February 23, 2021 at 2:00 am

Question on plant availability and seed starting.

We love pickles and have done a bit of research to find small cucumbers that make excellent pickles (Boston, straight 8 etc) Do places like Bachmans and the like sell these plants in the spring or do I need to start from seed? Also, last year we were not able to find sugar snap pea plants so do I need to start those from seed as well? Lastly, do I need a growing light to start all plants from from seed? #neverdonethisbefore I cleared brush and built a raised bed last summer. A u-shape with door and 6ft fencing and put in irigation drip lines so once I plant they really take off.

open for any and all suggestions

Mary Lahr Schier on February 24, 2021 at 4:14 pm

Joe — you will find a variety of vegetable plants at Bachman’s and other nurseries in spring. You could also check local farmers’ markets, which sell plants early in the season. For indoor seed starting, lights are a good idea, though cucumbers can be started outside in the ground in later spring and still do well. Here’s a blog post with details on seed starting:

Sounds like you have a great set up for your garden!

Leafy greens

Anyone’s February seed starting schedule begins with some greens. The following are some ideas of varieties you can plant and when to get them started.


Look for hardy varieties, leaf lettuces do better than head lettuces this early in the year. Also despite the name summer crisp lettuces also do well in the early spring.


Spinach is very hardy and does well when planted early. Remember to use larger containers for spinach to help those tap roots transplant well.


Swiss Chard seedlings transplant well and are very hardy.


This nutritional powerhouse does very well when transplanted out in the early spring. (And it tastes better)

Asian Greens

Don’t forget to plant a few tatsoi, mizuna or bac Choy! These plants do great in the spring and are very frost tolerant!

Winter Sowing – What to Do In Spring

When the weather starts to warm up in the Spring, you’ll be able to see your seeds sprouting. At this point you’ll need to make sure your new sprouts are getting enough water and ventilation. Poke a few more holes in the top of your containers and/or loosen some of the tape to allow for more air flow. The little seedlings will enjoy some days with the lids opened completely and then closed back in the evening.

Once it warms up and frost isn’t an issue, completely remove the lids. At some point, I will either divide and transplant the seedlings into bigger individual pots or directly plant them in my garden.

My winter sown plants are always very healthy looking plants. Here are a few of my successes from my winter sowing last winter. I’ve always wanted to have a large patch of Foxgloves, so I’m working on that patch of foxgloves by winter sowing. I’ve also had great success with Painted Daisies and the bunnies thoroughly enjoy this addition to the garden. Delphinium is another easy winter sown perennial and is always a lovely addition to any flower garden.

Depending on the perennials selected, the first year they may not flower, but the next year they will and they’ll just keep getting bigger and better each year. Is there a perennial you want to try, but don’t want to shell out the money for it? Winter sowing is a great way to get that perennial plant for practically nothing. So, go ahead and give winter sowing a try play around with it, experiment and keep track of what works best for you. You’ll be so glad you did!

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Learn More About Winter Sowing

If you would like to learn more about winter sowing, below are some links to additional resources:

Here is the original article that got me thinking about winter sowing that appeared in the Jan/Feb 2009 edition of Northern Gardener magazine. janfeb09itssoweasy

Here is another article written by Michelle that talks about winter sowing vegetables. I haven’t done this yet, but I’m hoping to give it a try this year. 38-41.SowVeg-NG-Jan.Feb_

Here is an article from This article was written by Trudi Greissle Davidoff, the person who originally came up with the idea of winter sowing. Trudi also has a Facebook group dedicated to Winter Sowing.

Are you looking for some other gardening activities you can do in the winter? If so, be sure to check out these posts:

Thanks a bunch for stopping by today to learn about winter sowing. Are you going to give it a try? Please leave a comment and let me know. Or, if you’ve already tried winter sowing, tell me about your successes.

Happy gardening (even in winter),

p.s. Follow Gingham Gardens on Pinterest for lots of great gardening ideas and tons of gardener’s eye candy. Gingham Gardens is also on Facebook – come say “hi.”

Shop Amazon to have your winter sowing supplies delivered right to your door.

Would you like more gardening ideas? Follow Gingham Gardens on Pinterest.

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