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? ›

If there's no information on the seed packet, you can pretty safely just start all your seeds about 6 weeks before you'll plant them outdoors. Make note of which plants are too big or too small at planting time, and then you can make adjustments next year based on your notes.

When to start seeds indoors list? ›

When should you get started?
  1. February is the optimal time to seed leeks, onions, and celery.
  2. 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.

How many weeks before planting should you start seeds? ›

If there's no information on the seed packet, you can pretty safely just start all your seeds about 6 weeks before you'll plant them outdoors. Make note of which plants are too big or too small at planting time, and then you can make adjustments next year based on your notes.

How many seeds per hole when starting seeds indoors? ›

Like most things in gardening, there are always exceptions to this rule of 2-3 seeds per hole. If you're planting large seeds like cucumbers, melons, or pumpkins, you should only use one seed per hole. However, you can still plant seeds close together and then thin them out once they've established themselves.

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.

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.

What seeds should not be started indoors? ›

Not every vegetable should be started indoors. There are many varieties that can be planted right into the ground (direct-seed). These are usually the short season vegetables or root crops that don't always transplant well. They include lettuce, spinach, beets, carrots, green beans and others.

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.

When to start tomatoes indoors? ›

Quick to germinate and grow, tomato seeds are best sown indoors about six weeks before your average last frost date. (To determine your last frost date, ask a gardening neighbor or contact your Master Gardener program.).

Do I plant the whole packet of seeds? ›

If only a few plants are needed, it is not necessary to plant all the seeds in a packet. Surplus seed often can be saved for a later planting date. Keeping seed dry and cool or at least at room temperature in a closed container is best.

Should you water seeds right after planting? ›

You won't have to water after they are planted, preventing seed movement. Create a mini greenhouse by covering the seed tray with a plastic tray or plastic wrap. This will keep the moisture and warmth inside, and you shouldn't have to water again till after the seeds have germinated.

Should I start all my seeds indoors? ›

Not ALL seeds should be started indoors. In fact, most vegetables grow perfectly well when started outdoors and even prefer not to be transplanted. Ultimately, it's important to consider how each type of vegetable grows in addition to where you're growing it.

What month is best to start seeds indoors? ›

Mid-March is the best time to start many vegetables and annual flowers indoors for transplanting outside once the threat of frost has passed.

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!

How often do you water starting seeds indoors? ›

Most seedlings require water every day or every other day. First, check the soil moisture using your finger by checking the soil color near the drainage hole. If the soil feels or appears dry or brittle, irrigate thoroughly until water pours out of the bottom of the tray, then stop.

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.

Should you soak seeds before planting indoors? ›

If you're storing and sowing seeds inside, they won't go through a cold winter, which some need to signify it's time to wake up and grow. To ensure high germination rates, wake seeds up, and potentially speed up the process, soak seeds before sowing them to soften and loosen that outer protective layer.

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