Winter Kitchen Herb Gardens

by SCMG Stephanie Wrightson

Some food gardeners welcome the winter as a season to rest. Others are itching to get their hands in the dirt. While we wait for spring to arrive, we can apply container gardening principles to create a lovely and useful indoor kitchen window garden. When seasonally appropriate, herbs in pots can be moved outdoors or transplanted in the garden.

Available light and other cultural conditions will determine what herbs can be potted indoors.  The pot sizes will determine the maximum mature size of the herb planted as well as the number of herbs that can be planted in each pot. Almost any container with proper drainage can be used.

GENERAL PROPOGATION AND CULTURAL REQUIREMENTS:

• Most small-sized herbs can be grown individually in 6-inch pots and are happy in a sunny window. In a sunny enclosed porch, larger herbs can be grown in larger pots.
• Shop nurseries and seed catalogs for dwarf or compact varieties but not at the expense of flavor and fragrance. Relatively compact varieties of woody herbs include Origanum vulgare (oregano) ‘Country Cream,’  ‘Polyphant’ or ‘White Anniversary,’ Rosmarinus officinalis (rosemary) ‘Blue Boy,’ Thymus vulgaris (thyme) ‘Hi Ho,’ and Salvia officinalis (sage) ‘Compacta,’ ‘Nina’ or ‘Minimus.’
• Include herbs that are not winter-hardy such as basil (Ocimum basilicum). ‘Genovese’ is an Italian basil that is often used in pesto recipes. Purple-leaf basil is tasty and attractive in a green salad – try ‘Purple Ruffles’ or ‘Red Rubin.’ Brayour parsley (Petroselinum crispum ‘Brayour’) is a dark green, curly variety used to season soups and sauces. P. neapolitanum, flat-leaf parsley, is the species called for in Italian recipes.
• Herbs can provide an interesting focal point in the room. For example, a thickly planted container with chives that are regularly snipped for cooking looks like a small, mowed lawn. Common chives (Allium schoenoprasum) have a mild onion flavor and can be used raw or cooked. Chinese chives (A. tuberosum) have a garlic-like flavor.
• Potted herbs are started by seed, cuttings or divisions. Also, you may purchase transplants for many common culinary herbs. Herbs with a taproot, such as dill (Anethum graveolens), should be planted by seed or left in their purchased container.
• Herbs that can be divided include chive, thyme and mint (Mentha spp.), among others.  
• Herbs that can be grown by cuttings include oregano, sage and rosemary, among others.
• Where branches that touch the ground will root, plan ahead and layer one or two low-lying branches to later pot indoors.
• If you are making cuttings or divisions from outdoor plants to move indoors, be sure to hose off any insects or eggs that might be present.  
• Place indoor plants in or near a sunny window. During winter, plants will not receive the optimal 14 hours of light. However, they will live with less. If there is not at least six hours of direct light, use a fluorescent “grow light” to simulate the ideal amount of light. Less than optimal light can result in leggy herbs.
• A container creates a very different environment in which a plant lives as compared to the garden bed. Plants in pots cannot draw water from the surrounding soil. Nor does water drain in the same manner. Therefore, potted herbs need good drainage as well as proper watering. Commercial potting soils along with pot drainage holes provide this.
• The two most common problems of potted plants are over-watering and under-watering. Water most culinary herbs thoroughly, but let the soil almost dry out between watering. Most need about one inch of water per week once established. However, as days lengthen, direct sun can affect the watering schedule. Insert your finger in the potting soil to determine when irrigation is required.  
• Most herbs require fertile soil; potting soil meets this need. Be cautious with the use of fertilizer on culinary herbs – over-fertilization will interfere with the development of oils that impart desired flavors.
• Regular harvesting of potted herbs will promote new growth. Do not strip all the leaves off the plant. Instead, use scissors or pinch off two or three stems, leaving at least half the growth in order to stimulate new growth. In general, do not allow herbs to flower. If you are unable to use potted herbs on a regular basis, keep them pruned.
• If you plan to move potted herbs outdoors this spring, slowly acclimate them to the change before leaving them outside for the entire day and night.

For the requirements of specific herbs, refer to individual herb articles on this site, the California Master Gardener Handbook, the Sunset Western Gardening Book of Edibles and science-based gardening websites. Peruse seed catalogs for unusual or dwarf varieties