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.

Crop

Weeks before final frost date to start the seeds

Artichokes

8 weeks

Basil

6 weeks

Broccoli

4-6 weeks

Brussels Sprouts

4-6 weeks

Cabbage

4-6 weeks

Calendula

6-8 weeks

Cauliflower

4-6 weeks

Celery

10-12 weeks

Collards

4-6 weeks

Echinacea

6-8 weeks

Eggplant

8-10 weeks

Kale

4-6 weeks

Leeks

8-10 weeks

Marigolds

6-8 weeks

Morning Glory

3-4 weeks

Mustard

4-6 weeks

Okra

4-6 weeks

Onions

8-10 weeks

Oregano

4-6 weeks

Parsley

9-10 weeks

Peppers

8 weeks

Sage

6-8 weeks

Spinach

4-6 weeks

Swiss Chard

4-6 weeks

Tomatoes

6-8 weeks

Yarrow

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)

FAQs

Seed-Starting Chart: When To Start Seeds Indoors? ›

When should you start seeds indoors? Start seeds six to eight weeks before the last frost in your area. 2 Most plants are ready to go outside four to six weeks after you start the seeds.

When should seeds be started indoors? ›

When should you start seeds indoors? Start seeds six to eight weeks before the last frost in your area. 2 Most plants are ready to go outside four to six weeks after you start the seeds.

How many seeds per hole when starting seeds indoors? ›

Most seeds prefer a depth of about 2 times their length. The tiniest seeds can be sprinkled directly on the surface. Cover the seeds with a thin layer of soil. Plant about 3 seeds per hole (more if using older seeds) and once they germinate, thin down to leave only the strongest seedling.

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.

Is February too early to start seeds indoors? ›

If you can't wait to sink your hands into the dirt, don't wait any longer—at this point, you can begin planting some of your favorite veggies! There are plenty of seeds that you can start indoors in February, and even a few that you can direct-sow outdoors.

What happens if you start seeds indoors too early? ›

But, starting your seeds too soon is still a problem. How? Seeds sown too early will result in bigger plants which then need to be potted up into bigger containers which quickly take over your seed starting area/house and cost you more money is potting soil, organic fertilizer and pots.

How do you start seeds 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 often do you water starting seeds indoors? ›

Indoor Watering

Indoor seedlings generally need water every 2-3 days.

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.

Should you water seeds right after planting? ›

Using a small plastic tub or tray, add in your soilless mix. Then pour in just enough water to saturate it to “wrung-out sponge” wetness. The idea here is that the soil is already moist when you plant your seeds, so you don't have to worry about watering for a few days.

Are egg cartons too small for seedlings? ›

Egg cartons are for eggs. Not for starting seeds. They simply have too little soil to grow any seedling well without potting up; potting them up without disturbing their roots is not possible with their curvaceous sides.

How often do you water seedlings in egg cartons? ›

Place the egg carton on a tray and keep it in a warm light-filled location indoors until the seeds begin to sprout. Remind your child to water the seeds every day or as directed on the seed package.

Do egg cartons float? ›

Egg cartons are light, so they should easily float. If you're using cardboard, it may absorb water and eventually get too wet.

Is January too early to start seeds indoors? ›

It's still too early for many Northern states to start their transplants indoors, but some warmer Southern states are ready to get going! Tomatoes, Peppers & Eggplants (Zones 8-10): If you live in Zones 8-10, get a head start on the growing season by starting your tomato, pepper and eggplant seeds indoors.

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.

What are the best vegetable seeds to start indoors? ›

Best Plants for Indoor Seed Sowing
  • Broccoli.
  • Brussel Sprouts.
  • Cabbage.
  • Cauliflower.
  • Eggplant.
  • Kale.
  • Lettuce.
  • Onion.

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.

Should you soak seeds before planting indoors? ›

By soaking the seed, it enables the new growth from the inside to push through the hard shell and grow. The seeds that could benefit from a good soaking include: corn, pumpkin, beans, chard, beets, and peas. The seeds you shouldn't soak include: carrots, lettuce, radish, celery, turnips, and spinach.

Do I need grow lights 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.

Can egg cartons be used to start seeds? ›

You can use egg cartons as a seed-starting tray! Depending on the type of carton you have, you can even cut apart the individual sections and plant them, as the carton will biodegrade. Be sure to poke small holes for drainage, and put the cartons on a tray or in a shallow pan to catch any residual water.

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