First, you must understand my fundamental nature. I, Thyme, am a woody-stemmed perennial herb. In my native Mediterranean home, I am built to survive for several years, enduring mild, wet winters and hot, dry summers. My survival instinct is to become dormant during the cold season, much like a bear hibernating. I significantly slow my growth, conserving energy within my tough, woody stems and root system. However, my tolerance for freezing temperatures has limits. A hard frost can damage my tender, newer growth, and a deep, sustained freeze can kill my roots if they are not adequately insulated by snow or mulch. Therefore, when you ask if I can survive winter indoors, the answer from my perspective is a resounding yes, provided you replicate the conditions of a successful dormancy period, not a summer growth season.
This is the most critical and stressful event of my year. A sudden change from the bright, humid outdoors to a dark, dry house is a shock to my system. Please do not wait until the first frost to bring me inside. Instead, move me several weeks before nighttime temperatures consistently drop below 50°F (10°C). This gradual approach allows me to acclimate. Begin by placing me in a shaded, sheltered outdoor spot for a week, then perhaps a cool garage or porch, and finally to my indoor winter home. This process, called hardening off in reverse, helps me adjust to lower light levels without going into severe shock, which can cause me to drop my leaves and weaken significantly.
My needs indoors are specific. I do not wish to grow vigorously; I simply wish to rest comfortably.
Light: I crave as much direct sunlight as possible. A south-facing windowsill is ideal. East or west-facing can be acceptable, but a north window will likely not provide enough photons for me to sustain myself. Without sufficient light, I will become "leggy," stretching my stems weakly toward the light source, and my leaves will pale. I am essentially starving for solar energy.
Temperature: I do not want to be warm. Remember, I am dormant. A cool room between 40-60°F (5-15°C) is perfect. A heated living room at 70°F (21°C) will confuse my internal clock, potentially forcing me to produce weak, spindly growth while the low winter light is insufficient to support it. An unheated sunroom, a cool basement with a grow light, or even a bright but chilly spare room are far better than a warm windowsill above a radiator.
Humidity: Indoor winter air is desiccating. My small leaves lose moisture quickly to the dry air. While I am drought-tolerant, extreme dryness can stress me and make me more susceptible to spider mites. Please consider grouping me with other plants to create a slightly more humid microclimate or using a small humidifier nearby.
My water needs plummet during dormancy. My metabolism is slow, and I am not growing. Overwatering is the single greatest threat to my survival indoors. Soggy soil will suffocate my roots and lead to fatal root rot. Please water me only when the top inch or two of soil is completely dry. When you do water, water thoroughly until it runs from the drainage hole, but then allow me to dry out considerably again. As for food, I require none. Do not fertilize me during the winter. Fertilizer would encourage growth that I cannot support, further weakening me.
The stress of the indoor environment, especially low humidity and incorrect watering, can make me susceptible to pests like spider mites and aphids. These tiny creatures suck the sap from my leaves, further depleting my energy reserves. Please inspect my leaves regularly, especially the undersides. A strong spray of water or an application of insecticidal soap can help manage an infestation if caught early.
