Chamomile is a popular herb, with two main varieties: German (Matricaria recutita) and Roman (Chamaemelum nobile). German chamomile is the variety most frequently started from seed indoors to produce annual flowering plants. Starting seeds indoors offers growers a significant advantage by bypassing unpredictable early spring weather. This controlled environment protects delicate seedlings from temperature fluctuations and pests, ensuring a stronger start. The practice also accelerates the plant’s development, leading to an earlier harvest of the fragrant flower heads.
Determining the Ideal Sowing Window
The precise timing for sowing chamomile seeds indoors is dictated by the average last frost date. Gardeners should consult local resources or historical weather data to determine this date. Once known, the ideal sowing period is established by counting backward approximately four to six weeks.
Starting seeds too early, such as eight to ten weeks before the last frost, often results in weak, spindly seedlings, a condition known as legginess. These plants have excessively long stems as they strain to find adequate light. They are poorly equipped to survive transplantation outdoors and are highly susceptible to damage.
Delaying the indoor start too long can mean missing the optimal growing season entirely, reducing potential yield and delaying bloom time. Chamomile requires time to mature before flowering, making a timely start important for a summer harvest. A compressed schedule leaves less time for the plant to establish a robust root system before summer heat arrives.
Aiming for the four-to-six-week window ensures seedlings are mature enough to handle the transition outdoors but not overgrown or weak. This approach maximizes the interval between germination and the final safe planting date. Careful calibration prevents both premature and delayed starts.
Essential Supplies and Indoor Setup
Successful indoor starting requires specific equipment, beginning with the correct containers. Shallow trays or individual peat pots are suitable, provided they offer drainage holes to prevent waterlogging and fungal diseases like damping off. Sterilizing containers before use helps prevent pathogen transfer.
The growing medium must be sterile and fine-textured, such as a specialized seed-starting mix. These mixes are lighter than garden soil and designed to retain moisture while remaining loose for delicate root development. They lack the density and potential weed seeds found in standard soil, creating a healthier environment.
Proper light is the most important factor for producing robust seedlings. A sunny windowsill is rarely sufficient, especially during late winter, as light intensity and duration are inadequate for stocky growth. Low-angle winter sunlight often leads to etiolation, causing plants to stretch excessively.
Supplemental lighting, such as fluorescent shop lights or dedicated LED grow lights, should be positioned a few inches above the plants. Chamomile seedlings benefit from 14 to 16 hours of light daily to prevent stretching and maintain compact growth. A specialized heat mat can also provide consistent warmth and encourage faster germination rates.
Sowing Techniques and Germination Care
Sowing the tiny chamomile seeds requires a delicate approach. Chamomile is a photoblastic seed, meaning it requires light for germination, so seeds must be surface-sown and not buried. Gently scatter the minute seeds across the surface of the moistened mix, then lightly press them into the soil without covering them.
Moisture management is delicate, as the surface must remain consistently damp without becoming saturated. Misting with a spray bottle avoids dislodging seeds or overwatering. Bottom watering, by placing the tray in a shallow basin, helps the medium wick up moisture without disturbing the fragile seeds.
A moderate temperature range, ideally between 65 and 70 degrees Fahrenheit, facilitates rapid germination within one to two weeks. After emergence, maintaining this temperature and sufficient light prevents seedlings from becoming weak and leggy. High humidity can be maintained by covering the tray with a clear plastic dome until the first sprouts appear.
Once seedlings develop their first true leaves, they must be thinned to prevent overcrowding. Snip the weaker seedlings at the soil line, leaving the strongest plants spaced about two inches apart. This ensures remaining plants have adequate air circulation, nutrients, and light to develop into sturdy transplants. Crowding leads to competition and stunted growth.
After thinning, reduce watering frequency slightly, allowing the soil surface to dry between applications. This reduction helps the root system grow deeper and become stronger in preparation for the outdoor move.
Hardening Off and Transplanting Outdoors
The transition from the controlled indoor environment requires a careful, gradual process known as hardening off. Skipping this step subjects tender seedlings to sudden shock from wind, sun, and temperature swings, which can severely damage or kill the plants. This acclimatization typically takes seven to ten days.
Begin by placing seedlings outdoors in a sheltered, shaded area for just one or two hours on the first day. Over the following week, progressively increase the duration of exposure and gradually move them to areas receiving more direct sunlight and wind. This slow introduction allows the plant cells to develop thicker walls and a tougher cuticle layer.
Always bring the plants back inside at night if temperatures drop below 50 degrees Fahrenheit. Final transplanting outdoors should only occur after all danger of frost has passed. Nighttime temperatures must consistently remain above 50 degrees Fahrenheit before the young plants are permanently set into the garden soil.
When transplanting, set the seedlings at the same depth they were growing in their containers, taking care not to damage the delicate root ball. Space the plants about six to twelve inches apart. This spacing allows for proper air circulation, gives mature plants room to bush out, and maximizes flower production while minimizing the risk of powdery mildew.