When To Start Seeds Indoors: Zone 5 (2024)

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If you live in zone 5 like I do, then you know it is important to start your seeds before you can plant them outdoors. If you aren’t sure when to start seeds indoors in zone 5, keep reading to find the perfect time to start your seeds.

When to start seeds indoors zone 5

When we look at starting vegetable and flower seeds indoors, we need to focus on the average last frost date. This is the starting point that will allow us to count backwards for starting our seeds.

If you are unsure of your last frost date you can enter your address here to get it. Remember that these are averages and every year can be a little different.

For most of zone 5 our last frost date is mid May specifically the 15th for my location. If you have a similar last frost date, then you can follow the below dates to start your seeds.

Vegetable Seeds To Start Indoors

There are many common vegetables like tomatoes and peppers that need to be started indoors. Here is a list of common vegetables that need to be started indoors for zone 5.

Tomatoes

Tomatoes should be started indoors during the first and second week of March. This is because tomatoes need to be started 6-9 weeks before your last frost date.

Peppers

Peppers should be started indoors on the first of March. It can take a long time for pepper seedlings to grow and a heat mat will help them grow better!

Eggplant

Eggplants should be started during the first week of March. This gives your eggplants enough time to grow before they are transplanted, and it ensures you will have an eggplant crop over the summer.

Tomatillo

Just like tomatoes, tomatillos should be started during the first week of March.

Cabbage

If you are starting cabbage seeds indoors, you should plant them no earlier than March 1st. This will ensure that the plants don’t grow too big before they need to be transplanted.

Cabbage does not need to be started indoors, but if you want a head start on the season you can start them indoors.

Broccoli and Cauliflower

Both broccoli and cauliflower should be started indoors during the first week of April. Broccoli and cauliflower can withstand cool temperatures, so you may be able to plant them outside early.

Onions

Onions should be planted during the last two weeks of February. It can take a long time for onions to grow from seed, so it is necessary to start them early.

Brussel Sprouts

Brussel sprouts should be started during the last week of March or the first week of April. These are actually grown for a fall harvest even though you plant them in spring.

Herbs To Start Indoors

Herbs can be very expensive to buy, so it is a great idea to start your own from seeds. Here is a list of herbs that are perennial in zone 5. Here is when you should be starting herbs from seeds in zone 5.

Basil

Basil seeds should be sown indoors during the last two weeks of March. All basil plants are extremely frost sensitive, so don’t plant it outdoors until the risk of frost is long past.

Chives

Chives should be sown during the last two weeks of March. This plant is a perennial herb in zone 5, so you only have to plant them once.

Cilantro

Cilantro should be sown indoors during the last week of March. You can continue to sow cilantro every other week so you have a continuous supply of fresh cilantro.

Fennel

Fennel seeds should be started during the third week of March.

Calendula

Calendula should be started during the second to third week of April. This herb can grow quickly and has big leaves so make sure to plant it in medium sized pots.

Parsley

Parsley should be sown during the second or third week of March. Just like cilantro, parsley can have successive plantings to keep you in supply of fresh parsley.

Flowers To Start From Seed Indoors

Planting flowers in your garden is a great way to attract pollinators. Here is when you should start some common flower varieties indoors.

Marigold

Marigold doesn’t need to be started indoors; however, if you want earlier blooms, you can start them indoors during the last week of March.

Zinnia

Just like marigolds, zinnia seeds can be started indoors, but they don’t need to be. You can start zinnia seeds during the first week of April.

Borage

Borage can be started during the second week of April. Flowers from the borage plant are edible and they taste like cucumbers.

Yarrow

Yarrow can be started during the third week of March. You can also sow yarrow during the fall and it will sprout when the weather warms in the spring.

Echinacea

Echinacea should actually be sown outdoors as the seeds require cold stratification to germinate. You can learn how to grow echinacea from seed here.

Buzz buttons

Buzz buttons should be started during the last two weeks of March. This plant’s flowers can numb your mouth and the petal-less flowers look amazing. You can learn how to grow buzz buttons here.

When To Start Seeds Indoors: Zone 5 (10)

What do I need to start seeds indoors

Now that you know when you should be starting your seeds, you may wonder what you need to start your own plants from seed.

Don’t make the same mistake I did and neglect buying the necessary equipment for starting seeds. I thought that you didn’t need any of this equipment, but I was soon proved wrong.

I now have the below tools for my seed starting setup and it works great!

Grow light

The most important thing you need to start seeds indoors is a grow light. The sunlight coming through a window will not supply the needs of your seedlings to grow healthy.

A good grow light is needed for your plants to grow properly. This is what I am currently using for my seedlings. If you have a grow light you can start your seedlings anywhere that is warm.

When To Start Seeds Indoors: Zone 5 (11)

Heat Mat

While some seedlings don’t need a heat mat to grow, peppers, tomatoes, eggplants, and tomatillos do need them. I have a much better success rate with my peppers now that I use a heat mat.

These mats heat the potting soil to encourage the seedlings to sprout. You can find the same heat mat that I use here.

Pots and Potting Soil

And, of course, you will need to buy or make quality potting soil and buy seedling trays.

Those are the main things you need to start your own seedlings.

What seeds shouldn’t be started indoors

There are a few plants that will not enjoy being transplanted, so it is best not to start them indoors. For example, carrots don’t like to be transplanted because they have sensitive roots so it is best to direct sow them.

Most plants that are grown for their roots or have tap roots should not be started indoors. Other plants like cucumbers and beans just don’t do well after transplanting.

For these types of vegetables it is just better to direct sow them in the garden. If you really need a boost on the growing season, you can grow these seeds in decomposable pots so you don’t have to disturb the roots.