6 Best Flower Seeds to Start Indoors - Backyard Boss
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6 Best Flower Seeds to Start Indoors

Starting flower seeds indoors is a great way to get a jump start on the growing season! While some seeds need direct outdoor sowing, there are plenty of flowers that benefit from an early start indoors. Not only do you enjoy blooms earlier, but you can also choose flower seeds for plants not readily available in your local nursery.

Seeing the beginnings of life growing up from the soil is a fun and rewarding process, and with a bit of planning, you can be on your way to your spring garden dreams in no time. Discover the best flower seeds to start indoors!

Flowers to Start Indoors

If you enjoy early spring blooms, starting seeds indoors will give you a head start on the growing season and ready to enjoy the warm weather. Have a look at these six best flower seeds to start indoors and start envisioning your spring garden now!

1. Snapdragons

Pink Snapdragons
Image credits: hartono subagio via Pixabay

Snapdragons make wonderful additions to gardens. The beautiful, upright, cool season blooms produce the best quality flowers in spring and fall. Starting snapdragon seeds indoors and then transplanting them helps to set their roots before flowers bloom. Start the seeds six weeks before transplanting outdoors (usually in April, depending on your zone) once the soil is workable. These perennials are hardy and can handle some light frost.

Pro Tip: You can also start snapdragons indoors in early fall and plant them outdoors about eight weeks before the first fall frost to germinate in the ground over winter.

2. Marigolds

African Marigold
Image credits: Dinesh Valke via Creative Commons

Marigolds are a popular choice for gardens due to their easy-to-grow nature and long-lasting flowers. There are three varieties to choose from: ‘Signet,’ ‘French,’ and ‘African’ marigolds. ‘African’ marigolds are the largest of the three varieties of marigolds, reaching up to 3 to 4 feet with ‘Signet’ staying the smallest at around 6 inches.

Begin marigold seeds indoors to get these into the garden as soon as possible, as they bloom in the spring and the fall. Do so about four to six weeks (or eight weeks for African marigolds) before the last frost. These beautiful flowers germinate quickly, about five to seven days after seeding.

3. Zinnias

Zinnia orange flower
Image credit: Hermann via Pixabay

Zinnas have an easygoing nature with many colors, heights, and abundant blooms. No wonder these annuals are one of the more popular flower choices for gardens!

To get a jumpstart on the growing season, start these seeds indoors for about six weeks before transplanting them outside. With an established transplant, you can put it in the ground once the soil is around 60 degrees Fahrenheit, which is earlier than planting seeds directly outdoors. When sowing seeds directly into the garden, you must wait until after the temperature has reached 70 degrees Fahrenheit.

4. Cosmos

pink cosmos flower against a light blue sky
Image credits: kkw0812 via Pixabay

Cosmos makes an excellent garden filler due to the profuse growing nature and long blooming season (mid-summer to fall). These annuals come in many different colors and attract pollinators such as butterflies. What’s not to love?!

You can start cosmo seeds indoors four to six weeks before the last frost in your area. Once frost is no longer a danger, transplant the cosmos into your garden!

5. Sweet Alyssum

sweet alyssum small white flowers
Image credits: May_hokkaido via Pixabay

Looking for low widespread blooms? Sweet alyssum is the answer! These perennials (though commonly grown as annuals) have delicate flowers with a sweet honey scent and attract pollinators like bees and butterflies.

To start these seeds indoors, begin four to six weeks before the last frost. You will start to see growth around 14 days after starting the seed.

Pro Tip: Sweet alyssum requires light to germinate, so do not cover the seed with soil.

6. Sunflower

Yellow sunflowers outdoors
Image credits: Uschi_Du via Pixabay

Few flowers elicit that cheerful, sunny feeling quite like the sunflower. Growing these in your garden attracts pollinators, is visually appealing, and comes in a variety of sizes.

As a fast-growing flower, start these annuals about two to three weeks before the last frost. Use biodegradable containers to start the seeds, then transplant the entire container into the outdoor soil, which helps avoid damage to the root system. Indoor starts allow the blooms to emerge sooner than directly seeding into the garden.

Pro Tip: Typically, these flowers grow up to 6 feet, but if this does not fit in your garden, there are smaller cultivars such as ‘Teddy Bear’ or ‘Big Smile.’

Tips for Success

Tomato seedlings
Image credits: Iulian Pana via Unsplash

Some plants may not benefit from indoor starts and perform better when directly sown into the garden. Fast-growing plants (or starting the seeds too early indoors) produce thin plants that do not transplant well. For this reason, choosing the right flower and the right time to start is key! Larkspur, for example, does not transplant well and benefits from growing in place!

It is also essential to acclimate the transplants before fully planting outdoors. Doing so requires a slow introduction to the outdoors by bringing the plants out for the day and indoors at night over a few days. Always check the specific requirements for your flower seed choices.

Rooting for You!

Get a jump on the season by starting those flower seeds indoors. Not only can you begin to see blooms earlier than direct seed, but it also allows you to grow many plants that may not be accessible in your local area! From the sweet honey-scented alyssum to the sunny and cheerful sunflower, wherever your preferences lead, you can start your garden dreams early!

Do you enjoy starting seeds indoors? Share your favorite flower to start indoors in the comment section below!