When To Start Seeds Indoors (Easy Printable Sowing Plan) (2024)

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This indoor seed starting plan is designed for cold climate gardeners in Canada and the United States. Use this streamlined schedule to sow seeds right on time in the months and weeks leading up to last frost. It also includes recommendations for direct sowing outdoors.

This is part of a series, Indoor Seed Starting for Beginners | Sow Indoors Grow Outdoors, where I walk you through the process from seed to garden. It’s all the information I wish I had when I was getting started.

When To Start Seeds Indoors (Easy Printable Sowing Plan) (1)

Simple Indoor Seed Starting Plan

When To Start Seeds Indoors (Easy Printable Sowing Plan) (2)

This is a selection from the ebook,Seed Starting for Beginners: Sow Inside Grow Outside,sharing everything you need to know to start your own garden plants from seeds indoors.

If you would like the entire ebook with all the printable lists in one handy file,you can save it instantly here.

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This seed sowing plan is intended for cold climate gardeners in the United States and Canada.

The sowing instructions on seed packets tell us how many weeks before our average last frost date seeds should be started indoors. This can range from 3 to 12 weeks or more, depending on the type of plant.

To keep it simple, I created this streamlined sowing system. The seeds are grouped by start times in two-week intervals.

Sowing Groups

You can sow all different seeds using this plan including veggies, herbs, fruits, perennials, and flowering annuals. If you would like to save a copy, it’s available in the Resources section.

Step One

To get started, you need to know your average last frost date.

Find Your Frost Dates & Hardiness Zone

Plant Hardiness Zones | When To Start Seeds Indoors (Easy Printable Sowing Plan) (4) United States | When To Start Seeds Indoors (Easy Printable Sowing Plan) (5) Canada
These are listed on seed packets and plant tags to guide your choices.

Average Frost Dates | Use this calculator at Almanac.com. Enter your city and state or province to find your first and last frost dates and number of frost-free days.

Ecoregion | Learn about the native plant and animal species and environmental conditions specific to your region to better understand why your garden choices matter.

Learn More:

Step Two

Next, find the date closest to your average last frost date on the chart below.

This tells you the approximate date to start each seed group.

So which group do seeds belong to?

Check your seed packet. For example, if the instructions say to sow indoors 10 weeks before last frost, that’s Group 2.

Don’t worry if you are not exactly on schedule—I often get a few weeks behind but it all works out.

Also keep in mind that different varieties have different timing. For example, one type of broccoli might be in Group 2 but another could be in Group 5. Your seed packet will list the required indoor growing time.

When to Start Seeds Indoors

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Here’s an example

My last frost is approximately May 15 which, according to the chart, means seeds that should be started 12 weeks before last frost (Group 1) should be started on (or around) February 15.

Step Three

  • Organize your seeds by their sowing groups (1-5).
  • Mark your calendar and sow a new group every two weeks.

Need to get your seeds organized? This show two smart storage systems.

The printable garden planner is designed to help you map our your garden plans and keep notes just how you like them.

Sample Vegetable Seed Sowing Plan

All seeds are sown indoors unless otherwise noted.

Groups 1 & 2

10-12 Weeks (70-84 Days) Before Last Frost

Not many seeds should be started this far ahead, otherwise the plants will get too big before planting time or struggle with indoor growing conditions.

Exceptions include some special tomatoes, peppers, and onions with long growth cycles.

If your indoor temperature stays steady around 70°F (21°C)—give or take 5 degrees or so, most seeds will germinate just fine.

When To Start Seeds Indoors (Easy Printable Sowing Plan) (7)
  • Tomatoes | Tiny Time, Brandywine Red, Red Oxheart
  • Onions | Ailsa Craig
  • Early broccoli
  • Peppers | Habanero, Scotch Bonnet

Want to grow flowers too? This lists 30 perennial and annual flower seeds to start indoors.

This is also time to start woody herbs from seed including oregano, rosemary, thyme, and sage although growing from cuttings is much faster.

Group 2 & 3

8-10 Weeks (56-70 Days) Before Last Frost

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  • Artichokes
  • Asparagus
  • Peppers
  • Scallions
  • Parsley

Group 4 & 5

4-8 Weeks (28-56 Days) Before Last Frost

This is the busy time for indoor seed starting! Most of what we grow can be started at this time.

A few weeks before last frost your local plant nurseries may also begin selling starter plants. If you get some, be prepared to keep them protected from temperature swings until planting time.

When To Start Seeds Indoors (Easy Printable Sowing Plan) (9)
  • Basil
  • Brussels sprouts
  • Broccoli
  • Cauliflower
  • Cabbage
  • Celery
  • Celeriac
  • Cucumber
  • Collards
  • Kale
  • Melons
  • Tomato
  • Squash – Summer
  • Squash – Winter

Outdoor Seed Sowing Plan

Direct Sowing Vegetable Seeds

When a seed packet says sow directly, it means you are sowing the seed outdoors, usually in its permanent location as some seeds in this group don’t like being moved.

Root crops like carrots are particularly sensitive to transplanting so avoid this if possible.

Other direct sow seeds are fast-growers that have enough time to mature within our frost-free days so there is no need for indoor sowing.

This has tips on direct sowing outdoors in spring in the weeks leading up to last frost.

Use my notes as a general guide and always check your seed packets for exact outdoor sowing time.

6-8 Weeks Before Last Frost (When Soil is Workable)

Have frost cloths handy in case temperatures dip below 30°F (-1°C).

When To Start Seeds Indoors (Easy Printable Sowing Plan) (10)
  • Asparagus
  • Carrots
  • Peas
  • Onion
  • Radish
  • Turnip
  • Spinach
  • Parsnip

4 Weeks Before Last Frost

Most of these ones like the soil temperature 50°F (10°C) or a bit warmer.

When To Start Seeds Indoors (Easy Printable Sowing Plan) (11)
  • Arugula
  • Brussels sprouts
  • Cabbage
  • Kohlrabi
  • Swiss Chard
  • Lettuces
  • Leeks
  • Mustard
  • Potatoes

Some cold-tolerant plants that have several true leaves can now be hardened off and then transplanted outdoors at this time. This includes cabbage, broccoli, Brussels sprouts, kale, lettuce, and kohlrabi.

2 Weeks Before Last Frost

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  • Beets
  • Broad beans
  • Pumpkin
  • Watermelon

Sow Directly Outdoors After Last Frost

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Once frosts are done, you can begin planting any starter plants you have—whether you grew them yourself or purchased them—but do it carefully. Warmth lovers like tomatoes are really sensitive to temperature drops.

You will harden off all your plants gradually (gradually get them accustomed to outdoor conditions) and have covers ready after planting in case some unusual weather is forecasted.

And, there are lots of seeds to sow directly in the garden (see suggestions below).

While indoor seed starting provides a good jump start, many of the same plants can be started outdoors when conditions are favorable. Plus, when early crops are done, it’s time to plant new ones in their place (known as “succession planting”).

Again, check your seed packets for specific sowing instructions.

  • Amaranth
  • Arugula
  • Broad beans – sow when ground is workable
  • Bush and Pole beans
  • Soya beans
  • Beets
  • Broccoli
  • Cabbage
  • Carrots
  • Celery
  • Celeriac
  • Chickpeas
  • Claytonia
  • Collards
  • Corn
  • Corn salad
  • Cress
  • Cucumbers
  • Endive / Radicchio
  • Kale
  • Kohlrabi
  • Leeks
  • Leaf Lettuce
  • Mescluns
  • Mustard
  • Okra
  • Onions
  • Pac choi
  • Parsnips
  • Peas
  • Potatoes
  • Pumpkin
  • Purslane
  • Quinoa
  • Radish
  • Rutabaga
  • Scallions
  • Spinach
  • Squash, summer
  • Squash, winter
  • Sunflowers
  • Swiss chard
  • Turnips
  • Zucchini

See What to Sow Midsummer Onward for growing into fall and winter.

Resources

Free Printable Seed Sowing Schedule

This seed sowing schedule is free to save to your device.

It’s a PDF document you can view in Adobe Reader and print out if you prefer.

Use it as the starting point and fill in the slots with your seed choices.

I’ve listed the sowing groups and seed examples to get you started.

Empress of Dirt

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Week-by-week Seed Starting Schedule

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Get Free Seed Starting Schedule

To save the file, please provide your email address for this purpose only.
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Buy Seeds

Ebook

When To Start Seeds Indoors (Easy Printable Sowing Plan) (15)

Seed Starting for Beginners
Sow Inside Grow Outside

by Melissa J. Will

NEW EDITION | Everything you need to get started with indoor seed starting for indoor and outdoor plants. Grow what you want—any time of year!

About This Ebook | Visit Ebook Shop

This ebook is a digital file (PDF format) you save to your device. It is not a physical product.

Buy Now$8 US

PayPal, Credit Card, Apple Pay

Available for Canada & United States only.

Ebook

When To Start Seeds Indoors (Easy Printable Sowing Plan) (16)

Growing Vegetables
A Weekly Indoor & Outdoor Seed Sowing Plan for Beginners

by Melissa J. Will

About This Ebook | Visit Ebook Shop

This ebook is a digital file (PDF format) you save to your device. It is not a physical product.

Buy Now$6 US

PayPal, Credit Card, Apple Pay

Available for Canada & United States only.

I hope this has helped organize your seed starting efforts. The most important part is to just get started, learn as you go, and gradually come up with your own best practices.

~Melissa the Empress of Dirt ♛

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When To Start Seeds Indoors (Easy Printable Sowing Plan) (2024)

FAQs

What month should I start my seeds indoors? ›

Planting seeds is also a great way to grow specific varieties. March is a great time to start seedlings indoors. Generally, start planting seeds indoors 6-10 weeks before the last frost date.

Is February too early to start seeds indoors? ›

Even if the last thing you're thinking about in January or February is the garden, it's actually a great time to start seeds indoors for frost-hardy leafy greens and for slow-to-get-started herbs.

When should you sow seeds and how do you figure that out? ›

Start by looking at the seed packet, which should tell you when to start seeds inside. Usually, it will say something like, "Plant inside six to eight weeks before last frost." Some types of vegetables, such as beans, are best started outdoors.

Can you start seeds indoors too early? ›

It is tempting to be thinking about starting seed now especially when we have sunny weather in the 60s. However, January is far too early to start most seeds and sowing seeds too early is just as bad, maybe worse, than starting them too late. You waste your time and money when you start seeds too early.

Can I start seeds in January? ›

Look through your catalogs and find the vegetable seeds for your garden. Some flower varieties should be started in January. In a warmer environment you can plant certain vegetables, but must be ready for a frost. Indoor herbs are always great to grow in a sunny windowsill.

What happens if you plant seeds too soon? ›

Planted too early in the year, seedlings can outgrow their pots before it's time to transplant them outside. This leads to rootbound seedlings—when roots become so tightly confined in a container that growth is stunted.

How do you start seeds indoors without grow lights? ›

Sow Your Seeds: Place 3-4 seeds per seedling planter. Gently push them down so that they are under the surface about 2 centimeters. This will make sure that they are protected and will absorb the right nutrients. If your seeds are especially small, leave them uncovered for a better chance at germinating.

Is March too early to start seeds indoors? ›

It's also a great time to sow a variety of seeds indoors so they'll be ready for early planting. Believe it or not, once you've prepared beds for them, you can start sowing seeds for many cool season veggies in March, along with broad (or fava) beans, which are some of the hardiest vegetables out there.

Can I start seeds indoors in March? ›

March is the perfect time to get those tomato and pepper seeds started indoors so they can be ready for an early spring planting! Also now is a great time to start planting cool weather vegetables that can withstand those last frost days of March and April.

When should I start seeds indoors for spring? ›

Early to mid-March is the best time to plant early season cold-tolerant plants like broccoli, cabbage, and head lettuce, and long-season heat-loving plants like peppers, okra, and eggplant. If you mainly just start tomatoes at home, you can wait until early April.

How many seeds should you plant per hole? ›

A pencil is a handy tool to make a hole and determine the correct depth. You can measure the point of the pencil ahead of time to denote a quarter or half inch. Place your seeds in the hole and bury them. Usually, you want to plant two or three seeds per hole because not every seed will germinate.

What is the best soil for starting seeds indoors? ›

Commercial seed-starting mixes, usually composed of vermiculite and peat, without any true soil, are recommended for starting seeds. They're sterile, lightweight and free from weed seeds, with a texture and porosity especially suited to the needs of germinating seeds and tiny seedlings.

When should I start tomato seeds indoors? ›

Aim to start tomato seeds indoors about six to eight weeks before your last frost date. So if your expected last frost date is May 10, for example, count back at least six weeks to March 29 as the day you need to get your tomato seeds planted.

How often do you water starting seeds indoors? ›

Watering. Check on your seedlings at least once or twice a day to see if they need misting. You want the surface of your soil to stay lightly damp because if your seeds dry out they won't germinate but if they stay too wet, they could rot. When at least 1/2 to 2/3 of the seeds sprout, you can remove the cover.

Do I need a grow light to start seeds indoors? ›

The natural light from a window is seldom enough for good, strong seedling growth. They will usually stretch and lean towards the light and will not produce sturdy plants. Sowing seeds indoors under fluorescent lights is the easiest way for the home gardener to control growing conditions and grow healthy transplants.

References

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