This is When You Need to Plant Your Garden Outside

While many people assume that the ideal time to plant a home garden is after the last frost of the spring, the truth is that knowing when to plant plants outside depends on several factors, the most important being your USDA hardiness zone and what plants you’re planning to cultivate.

Know Your USDA Plant Hardiness Zone

Climate and soil temperature both play key roles in when seeds germinate and what plants can thrive. Referring to USDA plant hardiness zones can help beginners and long-time gardeners alike better plan their gardens.

USDA plant hardiness zones are zones that the USDA defines as having a certain range of regular temperatures.

In years past, St. Louis, Missouri, was firmly in Zone 6. The USDA has recently upgraded most of the St. Louis area to Zone 7a, however, with “[o]nly the westernmost edge of the county remains in Zone 6B.” Being in Zone 7a means that St. Louis, Missouri, has an “average annual extreme minimum winter temperature” range of 0 degrees to 5 degrees Fahrenheit (-17.8 degrees to -15 degrees Celsius). Zone 6b means that the average annual extreme minimum winter temperature range is from -5 degrees to 0 degrees Fahrenheit (-20.6 degrees to -17.8 degrees Celsius).

Plants that do well in Zone 7a include:

• Clematis
• Hosta
• Butterfly weed

Plants that do well in Zone 6b include:

• Phlox
• Salvia
• Lilac

Understand Growing Seasons for Specific Plants

USDA hardiness zones can tell planters which plants (particularly perennials) can thrive in their area. But these zones don’t tell gardeners when the best time to plant seeds is.

Best Planting Time for Warm-Season Vegetables, Fruits & Flowers

Warm-season plants are those that thrive in the “early” planting seasons, growing in spring and early summer months. Spring planting time is after the last spring frost. For St. Louis, Missouri, the average last frost date typically occurs in mid April to early May.

Heat-loving fruits and veggies include:

• Cucumbers
• Okra
• Pumpkins
• Watermelons
• Other melons like cantaloupe

In addition to these warm-weather plants and vegetables, annuals like marigolds also love hot weather and make great additions to any flower garden early in the year.

Best Planting Time for Cool-Season Vegetables, Fruits & Flowers

Cool-weather plants are those that thrive in the “cool” planting seasons, growing in late winter through early spring and late summer through early fall. In St. Louis, Missouri, the first cool-weather planting season typically occurs in February through April, with fall planting season starting in August or September.

Cool-season crops to include in your fruit and vegetable garden include:

• Beets
• Radishes
• Parsley
• Apples
• Pears

Cool-weather flowers that tend to do well in the St. Louis area include perennials like daffodils, short-lived perennials like pansies, and annuals like petunias.

7 Planting Tips for Beginners

1. Use Mulch

Mulch is a great friend to gardeners; properly mulching a garden helps protect plants against fluctuating temperatures.

2. Plant Native Plants

Native plants encourage pollinators to visit your garden, helping your garden—and your local ecosystem—thrive.

Warm-season plants native to Missouri include butterfly milkweed and purple coneflower. Cool-season plants native to Missouri include hostas and coral bells.

3. Review the Seed Packet

Beginners may feel unsure of when the best time to plant is or even which plants can thrive in their area. If planters are ever unsure of which plants will thrive in their gardens and when the best time to plant is, they should check the back of their seed packets—they typically include USDA hardiness zones for the seeds and best times to plant.

4. Check Sunlight Tolerance

USDA hardiness zones and planting seasons are two major components when it comes to ensuring plants grow. Another factor planters should consider is shade or sunlight tolerance. Different plants grow best in different conditions, with some plants preferring shade and others craving sunlight.

Full-shade plants that do well in Zone 7 include Lily-of-the-Valley, astilbe, and hostas. Sunlight-loving plants that do well in Zone 7 include yarrow, echinacea, and lavender.

5. Prep for Next Year

Gardeners who want a head start on next year’s garden can plant plants with bare roots after the last frost of the spring. This timing helps them settle and bypasses the danger of frost to sensitive root systems.

6. Use a Raised Garden Bed

Planters who want to extend their growing seasons can use a raised bed, as raised gardens typically retain heat better than flat garden beds.

7. Hire Professionals

Gardening can be a fun, relaxing, and incredibly rewarding hobby. It can also be incredibly laborious and time-intensive. For those who want well-cultivated gardens but don’t have the time to care for one, hiring professionals can help. They can plan gardens, plant everything at the appropriate time, and maintain the garden to ensure everything thrives.