Growing Herbs Indoors

Essential Tips

Herbs make a great addition to a garden, but they can also be grown indoors. You can grow them as year-round houseplants or just in winter to protect tender herbs such as basil.

Growing herbs indoors offers many benefits, including:

• Fragrant foliage that invigorates your space
• Various foliage colors and shapes that add visual interest
• A constant supply of herb leaves for cooking
• Continual leaf production after the outdoor growing season ends

By cultivating herbs indoors, you can enjoy these advantages throughout the year. Below, we share essential tips to help you successfully grow herbs in your home.

Select the Right Herbs

Choosing the right herbs is crucial for successful indoor gardening. Some herbs thrive in containers, while others struggle.

Great options for your indoor herb garden include chives (Allium spp.), basil (Ocimum basilicum), and cilantro (Coriandrum sativum).

Avoid herbs with large root systems, such as horseradish (Armoracia rusticana), fennel (Foeniculum vulgare), and lovage (Levisticum officinale).

Herbs like tarragon (Artemisia dracunculus) are toxic to dogs and cats and should be avoided in homes with pets.

Cultivate the Best Conditions

Herbs, like many houseplants, have specific requirements for growing indoors. Conditions need to be just right for optimum growth or their health will rapidly decline.

Proper Sunlight

Most herbs need 6 hours of direct sunlight. Either place herbs in a sunny location, for example, near a window with a southern exposure, or place herbs 6 to 12 inches from two 40-watt, cool white fluorescent bulbs for 14 to 16 hours. These herbs do best in direct sunlight:

• Bay (Laurus nobilis)
• Rosemary (Salvia rosmarinus)
• Thyme (Thymus spp.)

These herbs can tolerate low light levels and only need 2 to 6 hours of direct sunlight:

• Lemon balm (Melissa officinalis)
• Chives (Allium spp.)
• Cilantro (Coriandrum sativum)

Herbs that are not exposed to their preferred light conditions will become thin and spindly, produce smaller leaves, and have a reduced aroma. If you grow plants on windowsills, rotate pots often so that each side gets enough light for uniform growth.

Ideal Temperature

Keep herbs in rooms with temperatures of at least 65 to 70°F during the day and 55 to 60°F at night. Although most herbs can survive temperatures in the mid to low 40s, others cannot; for example, basil (Ocimum basilicum) cannot survive temperatures lower than 50°F and should not be kept on windowsills during winter months.

Appropriate Humidity and Circulation

Herbs also require a balance between a humid environment and adequate air circulation. Air that is too low in humidity will cause leaves to dry out, while too much humidity can lead to root rot and other fungal issues. Homes and buildings with central, forced-air heating tend to have the driest winter conditions for indoor plants. In these situations, containers should be grouped to create a more humid environment. Other options for increasing humidity include setting containers in a pan of moist pebbles or near a humidifier. For spaces that are too humid, turning on a fan can improve air circulation. In late spring, summer, and early fall, air circulation can be improved by slightly opening a window.

Select the Right Containers

Plant and grow herbs in containers with a drainage hole and in a potting mix that will aid water drainage. Water the potting mix when it starts to dry out. Specific herbs such as bay (Laurus nobilis), marjoram and oregano (Origanum spp.), sage (Salvia officinalis), thyme (Thymus spp.), and rosemary (Salvia rosmarinus) should dry out slightly between waterings. When growing basil (Ocimum basilicum), never allow the potting mix to dry out completely.

Fertilize Wisely

Fertilize herbs with a low dose of water-soluble fertilizer every 2 weeks. Fertilizing herbs more often may negatively affect the herb’s aroma and taste. If using an organic fertilizer, check the ingredients list before applying. Some organic fertilizers have a pungent fishy or manure-like scent that can be unpleasant indoors.

Manage Pests

Cultural and mechanical methods should be used to control pests. Flying insects such as fungus gnats can be controlled by placing yellow sticky traps near the infested plants and using proper water techniques. For insects like aphids, trim off the infested branches and dispose of them in the trash. Soft insecticides such as neem oil or a Bacillus thuringiensis (Bt)-based product can be used (following all label directions) in extreme cases, but this is not typically recommended as herbs are meant to be regularly harvested and eaten fresh. Always wash leaves before you use them in a recipe.

Repot When Necessary

Repot herbs when roots grow through the drainage hole. The best time to repot is in the early spring so that herbs can grow into the new medium during the growing season. Perennial herbs can be repotted several times to accommodate new growth. Any herbs with a taproot, such as borage (Borago officinalis) and dill (Anethum graveolens), should be grown in deep pots. Herbs with a more trailing form can be grown in hanging baskets.

Prepare Herbs for the Outdoors

If you would like to place your herbs in containers outside during the late spring and summer months, they will need to be slowly acclimated to the higher light and wind intensities of the outdoors.

• Start by placing pots outdoors in partial shade
• Slowly expose them to more light every few days
• Continuously check the overall health of your plants to see if the fertilizer regimen or watering needs to be increased
• Look for any signs of insect infestation and damage and treat them as needed

Further Readings

Penn State Extension. “Enhance the Flavor of Food with Herbs.” 

Penn State Extension. “Harvesting and Preserving Herbs and Spices for Use in Cooking.”

Penn State Extension. “Growing Herbs Outdoors.”

Prepared by Elsa S. Sánchez, assistant professor of horticultural systems management, and Erin Kinley, state Master Gardener coordinator.