How to Grow Herbs in Zone 4

Visit a local garden center that specializes in herbs, then read the nursery tags carefully to determine what herbs may be appropriate for your climate. Some herbs, such as bee balm, comfrey, tarragon and mint may survive cold winters with a protective covering. Others, such as marjoram, rosemary and lemon verbena should be planted in containers and wintered indoors. Other herbs, such as basil, parsley and dill are annuals that will live only a single season. Most annual herbs can be planted in the ground or in containers.

Plant herbs after the last frost in spring, usually around mid-may in USDA hardiness zone 4. Take advantage of the short growing season by planting small bedding plants, as herbs grown by seed will take too long to establish.

Prepare the soil in the sunniest spot in your garden, as most herbs require full, day-long sunlight. Improve the soil, as herbs won't grow well in damp, cool, poorly drained soil. Improving the soil is especially important if your soil is clay-based or compacted. Spade or till the soil to a depth of 15 to 18 inches. Remove large stones or clods. Spread 4 to 6 inches of organic material such as manure, rotted leaves, shredded bark or compost over the top of the soil, then dig the organic material into the top 8 to 10 inches of oil.

Use a shovel or a trowel to dig a hole for each herb plant. Place the herb in the hole with the top of the root ball slightly above the top of the soil. Avoid planting herbs too deeply, as covering the top of the root ball can cause the herb to rot, especially in cool or damp soil.

Plant tender herbs in containers filled with commercial potting mix. Use containers with drainage holes in the bottom, as good drainage is crucial for herbs. As a general rule of thumb, one herb can be planted in each gallon of container space. Place the container in full sunlight.

Spread 1 to 2 inches of mulch around, but not on top of, the herb plants. A light layer of mulch will maintain an even soil temperature, keeping the roots warm during early spring, and cool during the hot days of summer.

Water herbs thoroughly after planting, then don't water the herbs again until the top 2 to 3 inches of soil feels dry. Allowing the soil to dry will provide good air circulation to the roots, and will help to prevent rot and fungal disease. Always water early in the day, as nights can be chilly in USDA zone 4, even during the summer. Watering early will allow the herbs to dry before the temperature drops. Water at the base of the plant and avoid wetting the foliage.

Bring container herbs indoors before the first freeze in autumn. Place the herbs in a sunny window and water when the top 2 to 3 inches of the soil feels dry.

Water in-ground herbs before the first freeze, as herbs stressed by lack of water won't withstand freezing temperatures. Water occasionally during the winter if the winter is dry with no snow cover.

Cut hardy perennial herbs down after the first hard freeze, leaving only 1 to 2 inches of stem remaining. Surround the plant with a cage made of chicken wire. The diameter of the cage should be about 12 inches wider than the diameter of the plant.

Fill the chicken wire cage with at least 6 inches of mulch. Use an insulating mulch such as straw, dry, chopped leaves or pine needles. Avoid wet leaves, which can become compacted. Mulch is especially important if the herbs aren't protected by snow. Replace the mulch throughout the winter if it blows away.