When To Plant Herbs In Missouri

Getting your herb garden started at the right time is the secret to a lush, productive harvest. If you’re wondering when to plant herbs in Missouri, the answer depends on whether you’re working with hardy perennials, tender annuals, or if you’re starting seeds indoors.

Missouri’s climate spans USDA hardiness zones 5b to 7a, meaning we get a full range of seasons. This includes late spring frosts and hot, humid summers. Your planting schedule must account for this to avoid losing plants to a sudden cold snap.

Understanding Herb Types and Frost Dates

First, know your last average spring frost date. In northern Missouri (like Kirksville), it’s around May 5th. Central areas (like Columbia) see it near April 20th. In the south (like Poplar Bluff), it can be as early as April 10th.

Your first fall frost is just as important. Northern Missouri can frost by October 10th, while southern regions might wait until late October. Mark these dates on your calendar.

Herbs fall into three main categories:

Hardy Perennials: These survive Missouri winters. Think rosemary (in sheltered spots), thyme, sage, oregano, mint, and chives. They can be planted in early spring, as soon as the soil is workable, or in early fall.
Half-Hardy Perennials: These herbs, like lavender and some rosemary varieties, need extra winter protection or are best treated as annuals in colder zones.
Tender Annuals: These herbs are killed by frost and must be replanted each year. Basil, cilantro, dill, and parsley (which is a biennial but grown as an annual) are common examples.

Spring Planting Schedule

Spring is the busiest planting time. You’ll be doing two main things: planting cold-tolerant herbs outside and starting warm-weather herbs indoors.

Early to Mid-Spring (March – Early April)

As soon as the ground thaws and is no longer soggy, you can plant hardy perennial herbs. You can also directly sow seeds for some hardy herbs right into the garden. Good choices for early sowing include:

Chives
Dill (it can handle a light frost)
Cilantro (it bolts in heat, so an early start is good)
Parsley
Chervil

Late Spring (After Last Frost – Late May)

Once all danger of frost has passed, it’s safe to plant tender herbs. This is when you transplant the basil, lemon verbena, and marjoram you started indoors. You can also sow seeds for fast-growing annuals like basil and summer savory directly into the warm soil.

Starting Herbs From Seed Indoors

Starting seeds indoors gives you a big jump on the season. It’s especially useful for slow-growing herbs or those that need a long, warm growing period.

Timing is Everything: Check your seed packet. Most herbs should be started 6-8 weeks before your last expected frost date. For central Missouri, that means starting seeds in mid to late March.
Use the Right Setup: Use a sterile seed-starting mix and containers with drainage. A sunny south window is okay, but grow lights prevent leggy seedlings.
Harden Off Seedlings: This is a non-negotiable step. About 7-10 days before transplanting outdoors, gradually expose your seedlings to outside conditions. Start with an hour in shade, increasing time and sun exposure each day.

Fall Planting and Overwintering

Fall is a fantastic, often overlooked, time for planting many herbs. The soil is still warm, the air is cool, and autumn rains provide good moisture.

In early fall (September), you can plant or divide hardy perennials like sage, thyme, and oregano. This gives their roots time to establish before the ground freezes. You can also sow seeds for cilantro and parsley for a late fall harvest.

For overwintering tender herbs like rosemary, you have a few options. You can dig it up, pot it, and bring it indoors to a sunny spot. Or, you can heavily mulch the plant in the ground and hope for a mild winter—this is riskier in northern Missouri.

Month-by-Month Herb Planting Guide for Missouri

March

Start seeds indoors for basil, oregano, sage, thyme, and marjoram.
Direct sow chives, dill, cilantro, and parsley seeds outdoors if soil is workable.

April

Continue indoor seeding for tender herbs.
Transplant hardy perennial seedlings or purchased plants outdoors.
Direct sow more cilantro and dill.

May

After the last frost, transplant all tender herbs (basil, etc.) outdoors.
Direct sow basil and summer savory seeds into the garden.

June

It’s not to late to plant fast-growing annuals from nursery pots or seed.
Make succession plantings of cilantro and dill for continuous harvest.

September

Plant or divide hardy perennial herbs.
Sow cilantro and parsley seeds for fall harvest.
Pot up tender herbs to bring indoors if desired.

October

Apply a light mulch around perennial herbs after the ground has chilled to protect roots from freeze-thaw cycles. Harvest remaining tender herbs before a hard frost.

Tips for Success in Missouri’s Climate

Missouri summers can be brutal. Choose a planting site that gets at least 6 hours of sun, but some afternoon shade can benefit herbs like cilantro and parsley, slowing down bolting.

Soil drainage is critical. Raised beds are excellent for herbs, which generally dislike wet feet. Amend heavy clay soil with plenty of compost to improve texture and drainage. Most herbs prefer a slightly neutral to alkaline pH, so avoid making your soil to acidic.

Water new plantings regularly, but once established, many Mediterranean herbs (rosemary, thyme, oregano) are quite drought-tolerant. Overwatering is a common mistake. Also, go easy on the fertilizer. Too much nitrogen leads to lots of leafy growth with poor flavor.

Common Herb Planting Mistakes to Avoid

Planting Too Early: Impatience leads to frost damage. Protect tender plants if an unexpected late frost is forecasted with cloches or row covers.
Crowding Plants: Give herbs room for air circulation. This prevents fungal diseases, which thrive in Missouri’s humidity.
Ignoring Bolting: Herbs like cilantro and basil will “bolt” (flower and go to seed) in summer heat. Plant them early and make succession plantings for a longer harvest.
Wrong Location: Planting sun-loving herbs like lavender in shade results in weak, leggy plants that are more susceptible to disease.

Frequently Asked Questions (FAQ)

What is the best month to plant herbs in Missouri?

There isn’t one single best month. For hardy herbs, early spring (April) is ideal. For tender herbs like basil, wait until late May after the last frost. September is also a great month for planting perennials.

Can I plant herbs outside in April in Missouri?

Yes, but only hardy perennial herbs and seeds for cool-season annuals like cilantro, dill, and parsley. Keep frost protection handy just in case of a late cold snap.

When should I start herb seeds indoors for Missouri gardening?

Aim to start your seeds 6 to 8 weeks before your area’s average last spring frost date. For most of Missouri, this means starting seeds in mid-March.

Is it to late to plant herbs in June in Missouri?

Not at all! June is a fine time to plant fast-growing annual herbs from nursery pots or direct seed. The soil is warm, which promotes quick germination for basil and dill.

Which herbs come back every year in Missouri?

Many reliable perennial herbs return each year. These include chives, mint, thyme, oregano, sage, tarragon, and lemon balm. Lavender and rosemary can be perennial but may need winter protection in colder parts of the state.

By following these timing guidelines, you’ll align your gardening efforts with Missouri’s unique seasons. Paying attention to frost dates and understanding each herb’s needs are the most important steps. With a little planning, you can enjoy fresh flavors from your garden from spring straight through to fall.