Spring Flower Guide: When to Plant, Soil Temperature, and More

While the long, gray winter lingers, you can and should make plans for a bright, colorful spring garden. Some flowers actually thrive in chilly conditions, and should be planted in fall to start blooming while there is still a little snow on the ground. 

Others will need to be placed either right before or right after the last frost. Depending on your particular climate, here’s how to choose what to plant and when in your yard for year-round curb appeal.

What to Consider Before Planting Flowers for Spring

There are a few variables to weigh before making a final decision as to when to plant spring flowers and which flowers to plant.

Climate

Do you live in an area with long winters, such as Ann Arbor, Michigan, or a place with no snow at all, like San Diego? The date of your last frost and your temperature’s soil will dictate when you can plant certain flowers. 

Look up your frost dates by entering your zip code on the Old Farmer’s Almanac website. If you’re planting after the last frost and live in a warmer climate, look for flowers that can handle the heat as summer approaches.

Plant Acclimation

Some flowers have already been acclimated to outdoor temperatures and environments by the nursery or garden center, so be sure to ask. If they haven’t, you should acclimate your flowers by placing them in a protected area in your garden during the day and bringing them back inside at night for a week or two. 

Plant Start

You can get a jumpstart on your spring flowers and grow some flowering annuals in hanging baskets or containers, preventing them from facing the cold, wet soil. However, air temperature is still a factor; delicate flowers shouldn’t be potted before frost has ended. Be sure to use a soilless mix, which will be warmer and drier than gardening soil. 

Soil Temperature

Some plants prefer warmer soil, while others like it colder. You can measure the soil temperature by placing a soil thermometer 4inches into the ground; make sure to check sunny spots as well as shady areas.

When to Plant Spring Flowers

Deciding when to plant flowers for spring is largely dictated by the factors described above as well as the type of flower you wish to plant. Here’s a guide to the various kinds of flowers and some rules of thumb for their ideal planting time.

Autumn

Autumn planting should happen before the first freeze of winter (usually October through November), when the soil is very workable. 

This is the time to plant spring-flowering bulbs, which require cold conditions to thrive, such as:

• Tulips

• Daffodils

• Flowering onions

• Crocuses

• Hyacinths

Very Early Spring

Very early spring is defined when the soil temperature has reached 45 degrees Fahrenheit and the ground is no longer frozen. Gardeners can work the soil without fear of overly wet conditions.

There’s also a simple way to tell. “If you can squeeze a handful of dirt and it falls apart easily without staying clumped together, it should be dry enough to plant,” says Tara Dudley, owner of Plant Life Designs. 

At this point, you can plant:

• Bare root perennials, like hellebore, evening primrose, and camellias

• Cold tolerant annuals, such as pansies and violas

Early Spring

Early spring is two to three weeks before the last frost has passed, and when soil warms up to about 65 degrees Fahrenheit. 

• Some annuals, such as snapdragons, nemesia, diascia, and osteospermum

• Potted perennials and shrubs, such as roses

Spring

Spring is when the threat of frost has passed for good. If an unexpected frost happens, make sure to cover sensitive plants to protect them. 

Spring is the time to plant flowers that can handle increasingly rising temperatures as we get closer to summer, such as:

• Petunias

• Black-eyed susans

• Hydrangeas

• Dahlias

If you don’t have a green thumb, consider hiring a gardener in your area.