When To Plant Herbs In Maryland

Knowing when to plant herbs in Maryland is the first step to a successful garden. Our state’s unique climate, with its humid summers and varied winters, means timing is everything for your herb beds.

This guide will walk you through the best planting dates, techniques, and tips tailored specifically for Maryland’s gardening zones. You’ll learn how to work with our seasons, not against them.

Maryland spans USDA Hardiness Zones 5b through 8a. This range means your planting schedule can shift by a few weeks depending on if you’re in the mountains of Western Maryland or on the coastal plain. The last average spring frost date is key. It ranges from early April in the south and east to mid-May in the higher elevations.

Understanding Your Maryland Garden Zone

First, find your specific zone. This will fine-tune the dates we discuss. Most of the Baltimore area is in Zone 7a. The Eastern Shore falls into Zones 7b and 8a. Western counties like Garrett are in Zones 5b and 6a.

Zone 5b/6a (Western MD): Last frost around May 15. First frost around October 15.
Zone 7a (Piedmont/Baltimore): Last frost around April 15. First frost around October 25.
Zone 7b/8a (Southern MD & Eastern Shore): Last frost around April 5. First frost around November 5.

Planting Cool-Season Herbs

These herbs tolerate light frosts and grow best in the cooler temperatures of spring and fall. They often struggle in Maryland’s peak summer heat.

Examples: Parsley, cilantro, dill, chives, chervil, and sage.
Spring Planting: Direct sow seeds or transplant seedlings 4-6 weeks before your last frost date. For Zone 7a, this means late March to early April.
Fall Planting: For a second harvest, plant these herbs again in late summer, about 8-10 weeks before your first fall frost. This is often late August in much of the state.

You can get a head start by sowing seeds indoors 6-8 weeks before you plan to move them outside. This works very well for parsley and chives.

Planting Warm-Season Herbs

These are your sun-loving, heat-thriving herbs. They are sensitive to cold and will be damaged by frost. Patience is key here—wait for truly warm soil.

Examples: Basil, oregano, rosemary, thyme, marjoram, and lemon verbena.
Outdoor Planting: Plant seeds or transplants after all danger of frost has passed and soil has warmed. For Zone 7a, this is typically mid to late May. On the Eastern Shore, you might start a week or two earlier.

Never rush basil or rosemary into cool ground; they will just sit there and sulk. Its better to wait for consistent warmth.

Special Case: Perennial Herbs

Many popular herbs are perennials in Maryland, meaning they come back year after year. The best time to plant these is in the spring or early fall.

Spring Planting (Best): Gives roots a full season to establish before winter. Plant oregano, thyme, sage, and mint in April or May.
Fall Planting: Can be done but aim for at least 6 weeks before the first hard freeze. This allows for some root growth.
Rosemary Note: Often treated as a tender perennial in Maryland. In colder zones, it needs winter protection or should be grown in a pot you can bring indoors.

A Month-by-Month Maryland Herb Planting Guide

This calendar uses central Maryland (Zone 7a) as a baseline. Adjust slightly for your location.

March – Early Spring Prep

Start seeds indoors for warm-season herbs like basil and oregano.
Direct sow cool-season herb seeds (parsley, cilantro) outdoors in late March if soil is workable.
Divide existing perennial herbs like chives and mint as new growth appears.

April – The Spring Push

Transplant hardened-off cool-season seedlings.
Direct sow more dill and cilantro sucesively for continuous harvest.
By mid-to-late April, you can plant hardy perennial starts (thyme, sage, mint) outdoors.

May – Transition to Summer

After your last frost date, the main planting begins.

Transplant warm-season herbs (basil, rosemary) outdoors.
Direct sow basil seeds into warm soil.
Harvest from your cool-season herbs regularly to keep them producing.

August – Plan for Fall

Sow seeds for cool-season herbs (cilantro, parsley) for a fall crop.
Take cuttings from basil and other tender herbs to root for indoor winter plants.

September – Fall Harvest & Planting

Transplant fall-started seedlings into the garden.
Plant new perennial herbs; the soil is warm but air is cool, perfect for root growth.
Harvest and dry or freeze remaining warm-season herbs before frost.

Step-by-Step: Planting Herbs Successfully in Maryland Soil

Maryland soil can be heavy clay. Herbs demand good drainage to thrive.

Choose the Right Spot: Most herbs need at least 6 hours of direct sun. Morning sun is especially beneficial.
Amend the Soil: Work 2-3 inches of compost into your garden bed. This improves drainage in clay and adds nutrients. Avoid high-nitrogen fertilizers, which can reduce flavor.
Plant at the Correct Depth: For transplants, plant at the same depth they were in their pot. For seeds, follow packet instructions—most herb seeds are tiny and need only a light covering.
Water Wisely: Water deeply after planting. Then, let the soil dry slightly between waterings. Herbs generally prefer slightly drier conditions.
Mulch: Apply a thin layer of mulch (like straw or shredded leaves) to conserve moisture and suppress weeds. Keep mulch away from the stems of plants to prevent rot.

Overwintering Tender Herbs in Maryland

Some herbs won’t survive a Maryland winter in the ground. With a little effort, you can keep them alive.

Pot and Bring Indoors: Before first frost, pot up rosemary, lemon verbena, and scented geraniums. Place them in a sunny south-facing window.
Provide Humidity: Indoor winter air is dry. Mist plants occasionally or use a humidity tray.
Water Sparingly: Plants grow slower indoors, so they need less water. Overwatering is a common mistake during this period.

Common Maryland Herb-Growing Challenges

Our humid summers can create issues. Watch for these common problems.

Powdery Mildew: Appears as white powder on leaves. Improve air circulation, water at the base of plants, and choose resistant varieties.
Root Rot: Caused by soggy soil. Ensure perfect drainage and don’t overwater.
Bolting: When cilantro and dill quickly go to seed in the heat. Plant in spring/fall, harvest often, and choose slow-bolt seed varieties.

FAQ: Planting Herbs in Maryland

What is the best month to plant herbs in Maryland?

There are two prime planting windows. April is best for cool-season herbs, and May is best for warm-season herbs. Early fall (September) is also excellent for perennials and cool-season crops.

Can I grow herbs in Maryland year-round?

Outdoors, no. But you can grow many herbs indoors on a sunny windowsill during winter. Chives, parsley, mint, and basil (from cuttings) do well inside with enough light.

When should I start herb seeds indoors for Maryland?

Start warm-season herbs (basil, oregano) 6-8 weeks before your last frost date. For Zone 7a, that’s mid-to-late February. Start cool-season herbs 8-10 weeks before your last frost, or simply direct sow them outside in early spring.

Is rosemary a perennial in Maryland?

It can be, but it’s risky. In Zones 7b and 8a, with a protected location and well-drained soil, it may survive. In colder areas, it’s safer to grow it in a container and bring it indoors for winter or treat it as an annual.

How do I protect my herbs from a late frost in spring?

Keep old sheets, frost cloth, or even cardboard boxes handy. If a late frost is forcasted after you’ve planted, cover your tender herbs in the evening. Uncover them in the morning once temperatures rise.

By aligning your gardening with Maryland’s climate rhythms, you can enjoy a lush, productive herb garden. Paying attention to frost dates and your specific microclimate makes all the difference. Start with a few easy herbs like basil and chives, and you’ll soon be adding more variety to your garden each season.