Seed-Starting Chart: When To Start Seeds Indoors? (2024)

All of the seeds are in hand, and the materials you need to start seeds are at your home. Now, you have to figure out when to start seeds indoors.

Starting seeds indoors at the right time is the first big step you have to take as a gardener. Incorrect timing could delay planting your seedlings outside or cause the seedlings to stay inside longer than needed, risking their overall health.

The average recommendation is to start your seeds six weeks before your final frost date in your area. Some seeds may be started eight weeks before this date or as soon as four weeks before hand. Look at each plant’s requirements before starting your seeds.

Let’s take a look at when to start seeds indoors at the right time to give your plants the best start.

Start a Seed Starting Journal

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I recommend that all gardeners have a seed starting journal where you write down the dates each year you start your seeds. It makes the following years easier.

By having a seed starting journal, you’ll know when you start your tomato seeds the previous winter and when you sowed your first row of carrot seeds. It’s also a place that you can write down observations to help in the upcoming years.

Perhaps one year, you started seeds too late; write that down so, in the following year, you don’t make the same mistake.

As you add more seed varieties and types, having a journal becomes an indispensable item. It makes creating a seed starting calendar much easier.

Not All Seeds Need to Be Started Indoors

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The first thing that you need to know is that you must start not all seeds indoors. Some plants are worse off if you start them in containers early because they are prone to becoming root-bound, making transplanting into your garden troublesome.

Here are the seeds that you can set aside and plan to sow directly outside.

I suggest that you store these separately so that you aren’t accidentally confused. Keeping them together makes it easier to find them later when it’s time to start sowing seeds outside.

Several annual flowers may be directly sown as well, such as:

  • Zinnias
  • Asters
  • Lavatera
  • Nasturtiums
  • Sunflowers
  • Bachelor’s Buttons
  • Nigella
  • Calendula

If your growing season is shorter, then consider starting a few of these plants inside if you have space. Perennial flowers usually must be started indoors.

Which Seeds to Start Indoors?

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Now that you sorted out your seeds that you can directly sow outside, here are the plants that you need to start inside and grown for transplant.

  • Artichokes
  • Basil
  • Broccoli
  • Brussels Sprouts
  • Cabbage
  • Calendula
  • Cauliflower
  • Celery
  • Collards
  • Echinacea
  • Eggplant
  • Kale
  • Leeks
  • Marigolds
  • Morning Glory
  • Mustard
  • Okra
  • Onions
  • Oregano
  • Parsley
  • Peppers
  • Sage
  • Spinach
  • Swiss Chard
  • Tomatoes
  • Yarrow

This isn’t an exhaustive list; it’s impossible to name all of the flowers and herbs you might want to start inside.

However, each seed packet will contain the information needed to determine when to start the seeds indoors.

When to Start Seeds Indoors?

Each plant has a different recommendation for when to start the seeds indoors. The general rule is that most annual vegetables should be started indoors six weeks before the final frost date in your area. Most seed packets list this information as well, stating something like, “start the seeds indoors six weeks before the final frost date.”

Figure out when to start your seeds indoors:

  • Know your Frost Date:Find yourUSDA hardiness zoneand use this information to determine when your final frost date is.
  • Growing Time:You need to know the average number of days between when you seedlings are big enough to put out in garden. On an average, most seeds starts to germinate from 13 days of sowing, depending on what you’re planting it may take 30 days to complete the germination process.
  • PlantingTime Is Important:For Cool weather crops likespinach, kale, lettuce and peasyou need tosow seedsindoors 8 to 12 weeks before the last frost date while the best time to plant seeds for warm weather vegetablessuch as peppers and tomatoes is 2-3 weeks before your desired planting date and you can start seeds inside 4 weeks ahead of last frost for crops like melons and cucumbers.

All recommendations for starting seeds are based on your final frost date, which varies from place to place. Knowing your first and last frost dates is valuable for all gardeners. Usea tool to find yourUSDA gardening zone and frost dates.

Once you figure out your last frost date for your area, mark this date on your calendar. Remember, this is no guarantee; rogue frosts happen after this date frequently, so it won’t replace keeping a close eye on your forecast before planting.

Use this data to decide when to start seeds indoors. For example, gardeners should start basil seeds six weeks before your final frost date. Find that day on your calendar and count backward six weeks. Mark that on your calendar as the day you need to start basil seeds.

Indoor Seed-Starting Chart

Use this seed starting chart of know when to start vegetables and herbs seeds indoors and then to transplant outside, based on the frost date date in your area.


Weeks before final frost date to start the seeds


8 weeks


6 weeks


4-6 weeks

Brussels Sprouts

4-6 weeks


4-6 weeks


6-8 weeks


4-6 weeks


10-12 weeks


4-6 weeks


6-8 weeks


8-10 weeks


4-6 weeks


8-10 weeks


6-8 weeks

Morning Glory

3-4 weeks


4-6 weeks


4-6 weeks


8-10 weeks


4-6 weeks


9-10 weeks


8 weeks


6-8 weeks


4-6 weeks

Swiss Chard

4-6 weeks


6-8 weeks


8-12 weeks

Can I Start Seeds Earlier?

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Yes, but starting seeds earlier will require some adjustments to make it work. If you start seeds in your basem*nt or somewhere cold, make sure the temperature isn’t too cold for the seeds to germinate. One to two weeks makes a considerable difference in temperatures in the spring.

It’s possible to put your started seedlings outside early with the right season extenders. Cold frames, greenhouses, row covers, and mini hoop houses give you the opportunity to place started tender seedlings outside several weeks earlier than planned.

I found that I can place started seedlings under mini hoops up to two weeks sooner than I planned to put them outside. Two weeks makes a big difference in growth, leading to a quicker harvest.

Can I Start Seeds Later?

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Yes, it’s possible to start seeds later than the recommended timeframe. If your seed starting location is warmer than 70℉, seeds germinate and grow faster, so you can remove a week off the schedule. Heat leads to faster growth; you might have large seedlings to transplant!

Even if the location isn’t as warm, starting seeds a bit later than planned isn’t the end of the world. It means that your harvest will be delayed slightly, but as long as you don’t enter your first frost date with unharvested summer crops, it’ll be fine.

Final Thoughts

Each plant has a different requirement for when to start seeds indoors. The general recommendation is to begin all annuals and perennials six to eight weeks before the final frost date in your region.

Some plants need to be started later or earlier; check the seed packet for further information to make sure your timing is appropriate.

Seed-Starting Chart: When To Start Seeds Indoors? (7)

Written By

Bethany Hayes

Bethany is a suburban homesteader, growing over half of the vegetables, fruit, and herbs that her family of six needs each year. She raises chickens and homeschools her children. When she isn’t spending time tending to her garden, you can find her reading, crocheting, and canning.

Seed-Starting Chart: When To Start Seeds Indoors? (2024)


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.

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.

What are the best conditions for starting seeds indoors? ›

Most seeds will not germinate without sunlight and will perform best with 12 to 16 hours each day. Indoors, place seed containers in a sunny, south-facing window and give the container a quarter turn each day to prevent the seedlings from overreaching toward the light and developing weak, elongated stems.

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 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.

Is it too late to start seeds indoors in April? ›

April is a great time to start to sow your flowers indoors so they can be ready for summer blooms!

Is it too late to start seeds indoors in May? ›

You may think it's too late to grow all your favorite vegetables from seeds, but warm May temperatures have made the soil perfect for sowing seeds. Warm soil will allow for fast germination and growing plants! Good choices are summertime kitchen garden staples like squash, beans, cucumbers and melons.

What vegetables can you plant in February and March? ›

February is a limbo land between winter and spring, but you can still get a surprising diversity of seeds into nursery pots or in the ground. In zones 8 and colder, you start long-season crops like leeks, onions, broccoli, peppers, tomatoes, and herbs with an indoor grow light setup.

What seeds to start earliest? ›

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.

What vegetables can I start growing in February? ›

Start Peppers & Eggplant Indoors

If you have somewhere warm to germinate seeds and, crucially, somewhere protected from the cold and most definitely frost-free to grow the resulting seedlings, then late winter is a great time to start off warm-season fruiting vegetables like peppers and eggplant.

What happens if I seed too early? ›

If done too early, some seed will germinate late in the season and those immature seedlings often won't survive the winter. Put down your seed while the ground is not frozen, but is still cold enough so germination of the grass seed will not occur until next spring.

How do you start seedlings indoors for beginners? ›

How to Start Seeds Indoors in 4 Easy Steps
  1. Fill a large bowl with seed-starting mix and mix in a little water to evenly moisten the soil. ...
  2. Place your seed tray inside the drip tray and fill each cell to just below the top with soil.
  3. Sow your seeds. ...
  4. Cover the tray and place it under your lights on the heat mat.
Feb 10, 2023

How long can seedlings stay in egg cartons? ›

But you also can't leave your seedlings in their egg cartons for too long, waiting for the weather to heat up. Seedlings should be moved to the garden once the roots reach the bottom of the tray, but before they start to grow into a circle.

Should you start all seeds indoors? ›

Though some plants prefer to be direct sown (like squash and cucumbers), almost anything can be started indoors as transplants, if done right, including root crops like beets, radishes and turnips. The main exception are vegetables with long taproots like carrots and parsnips, which need to be direct sown.

Can you start seeds indoors year round? ›

Starting seeds indoors during the winter is a great way for gardening enthusiasts to keep their sanity during the winter. It is also a perfect means for getting a jump start on the spring growing season. Seeds cost significantly less than seedlings and offer a much greater variety.

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.

What temperature do you start seeds indoors? ›

The closer the temperature is to the optimum, the quicker germination will occur. Most seeds germinate when the soil temperature is between 68° and 86°F.

How long does it take for seeds to sprout indoors? ›

Some are quick to germinate, taking 1-2 weeks at most, such as chillies, beans, sunflowers and pumpkins. Some seeds take more like 2-4 weeks, such as mango and parsley. Others, depending on how warm/cold it is, take closer to 2 months, for example avocado.

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