Best fast-growing flowers to grow from seed – 5 pretty picks

It’s easy to feel impatient after sowing seeds, as you wait for green shoots to emerge. But, there are some fast-growing options that show signs of life in just a few days, and – even better – go on to flower quickly.

Plant the following expert-approved picks in spring and you can enjoy a sea of blooms in summer. 

I’ve already sown some of these beauties for my cutting garden, and am so excited to see the results.

5 flower seeds to fill an outdoor space quickly

Prep flowerbeds and containers for a stunning display by planting these expert suggestions.

1. Zinnias

Meredith Bishop, a cut-flower grower of Bloom & Bounty, says, ‘Many growers have had zinnias germinate in as little as two to three days under favorable conditions (consistently moist and warm soil).' Blooming in around 65 days from planting, they make a top pick for easy, dependable, and low-maintenance cut flowers, she adds.

They require full sun and loamy soil to bloom continuously all summer long, Meredith continues. She recommends the 'Oklahoma' series (a mix of seeds is available from Burpee) and 'Benary’s Giant'.

Top tip: Rebecca Sears, a gardening expert from Ferry-Morse, advises deadheading zinnias regularly to prolong the flowering period.

Meredith Bishop

Meredith Bishop is an heirloom cut-flower grower in urban Nashville, TN. She operates a design studio called Bloom & Bounty with her organically-grown flowers, and enjoys writing, speaking, and leading all manner of gardening workshops.

Rebecca Sears

As CMO and resident green thumb for the Green Garden family of brands, Rebecca Sears nurtures the company's heritage but also looks to develop new products and solutions to help gardeners of all skill levels fuel their passion and become more successful in the garden. Rebecca has been gardening from coast to coast, first realizing her passion while living in Portland, Oregon, inspired by the public gardens throughout the city. When she relocated to the northeast, she built upon her knowledge and craft, and now her backyard garden grows larger each year.

2. Sunflowers

Meredith says sunflowers are some of the fastest seeds to germinate, both indoors and when directly sown into the garden. On average, it will take only five to seven days.

‘There are many varieties of sunflowers,’ she continues – ‘both day-neutral (plants which flower independent of the amount of sunlight received) and long-day plants. Some varieties of quick-to-harvest sunflowers include those among the day-neutral, single-stemmed “ProCut” series, such as “White Nite” or “Horizon”, with flowers ready to cut in just 60 days.’

‘White Nite’ sunflower seeds are available to buy from Burpee. 

‘An additional benefit to these hybrid varieties is that they have had pollen bred out of them, resulting in a less messy arrangement which won’t shed all over your table,’ she adds.

3. Sweet peas

Sweet peas are one of the best fragrant flowers and one of my absolute favorites. Mine are already starting to scramble up their support. 

Rebecca says, ‘This annual flower is known for its proliferation of blooms and fast germination rate of 10 to 14 days, making it a reliable choice for gardeners. Before sowing your seeds, I recommend soaking them 24 hours prior, as this can help them germinate faster and more consistently. 

‘Within 45 to 90 days, depending on the variety, you should have lovely vines with blooming sweet pea flowers gracing your garden.’ She suggests selecting an early-flowering variety (available at Ferry-Morse) for the speediest results.

4. Marigolds

Marigolds are cheery bloomers that make fantastic companion plants for vegetable gardens, and are quick to grow from seed.

Autumn Janus of Perfect Plants Nursery says, ‘Marigold seeds typically germinate within five to ten days, and start flowering in as little as eight to ten weeks. 

‘Seeds can be planted directly in the garden after the last spring frost,’ she says, recommending a sunny location with well-drained soil. ‘Space the seeds about 6–12 inches apart.’

Anna Ohler, the owner of Bright Lane Gardens nursery, says you can alternatively start marigolds indoors four to six weeks before the last frost date. ‘Keep the soil moist until seedlings emerge, and be sure to water young seedlings daily until they develop deeper roots,’ she says. ‘Thin seedlings if overcrowded.’

Burpee has a range of marigold seeds available to buy.

Autumn Janus

Autumn is a horticulture specialist and marketing professional at Perfect Plants Nursery. With four years of experience in the horticulture industry, she has developed a passion for helping people create beautiful indoor and outdoor spaces to enjoy. Her expertise in horticulture encompasses a broad range of activities, including plant care and selection, landscape design, and maintenance.

Anna Ohler

Anna is an avid plant hobbyist and the owner and operator of Bright Lane Gardens, a boutique plant nursery in Northern Michigan. With over a decade of experience in gardening and landscaping, she takes every opportunity to share her knowledge on all things plant-related. She also runs the company's YouTube channel, which is full of practical advice.

5. Nasturtiums

Another of my favorites, once settled in the soil nasturtiums are a great ground cover plant, and the hot-hued flowers brighten up a garden. According to Autumn, the seeds germinate within 10–12 days and plants start blooming in approximately six to 10 weeks.

Nastya Vasylchyshyna, a botany expert from Plantum, advises planting the seeds into the ground in late spring, after the danger of frosts has passed. ‘Dig the planting holes about 1 inch deep and 12–16 inches apart from one another, then sow two to three seeds per hole.’ Choose somewhere sheltered from strong winds and with a good amount of sun, as nasturtiums will grow weak and struggle to bloom in shade, she adds. 

You can also start the plants indoors around March, Nastya says. ‘Provide them with plenty of light.’ 

Try the ‘Alaska Mix’ nasturtiums from Burpee for variegated foliage.

Nastya Vasylchyshyna

Nastya is a professional botany expert for the Plantum app that helps identify plants and plant diseases and provides care recommendations. Her specialization is plant morphology, phytopathology, and plant physiology.

FAQs

What are some fast-growing perennial flowers to grow from seed?

When we think of fast-growing flowers, it’s easy to gravitate toward annual plants. However, some perennials can bloom in their first year if you sow them early enough and conditions are optimal. These include verbena, Erigeron karvinskianus, and echinacea.

How can you speed up seed germination?

Sowing flower seeds indoors often results in faster germination as you can control the environment more easily. 

Some larger seeds can be soaked in water before planting to soften their shell. Alternatively, you can put them on a damp piece of paper towel until they sprout. 

Once planted, ensure you keep the potting mix moist and plenty of light is provided. Warmth is also important – you may even want to invest in a propagator with a heat mat and lid to increase humidity (available from Amazon) for some seeds.

Need more advice for growing your best summer garden yet? Our guides on when to fertilize flower beds, how to water plants, and how to get rid of weeds will help keep your borders thriving.