Chamomile

German chamomile is not a summer herb. It germinates in cool soil, blooms in late spring, sets seed, and dies when the heat arrives — usually by late June in most climates. Gardeners who sow it in May alongside the basil and tomatoes tend to get a disappointing stand of leggy plants that bolt before producing more than a handful of flowers. The move that works is to treat chamomile like a cool-season green: sow it four weeks before your last frost, or in late summer for a fall crop.

The seed needs light to germinate. Press it into the surface of the soil but do not cover it — even a thin layer of soil can prevent sprouting. Water gently with a mist so the seeds stay in place. Germination usually takes one to two weeks if the soil stays damp and the temperature is between 55 and 65 degrees. Once the seedlings are up, thin them to about six inches apart; chamomile sown too thick produces weak, tangled plants with fewer flowers.

Chamomile tolerates poor soil and prefers it to rich ground. A bed that was heavily fertilized for tomatoes the previous year often produces tall, floppy chamomile with more leaves than flowers. Sandy or lean loam gives you compact plants with a higher proportion of blooms to foliage, which is what you want if you're harvesting for tea.

The flowers are ready to pick when the white petals have fully opened and begun to curl back slightly. The best time to harvest is mid-morning, after the dew has dried but before the day heats up. Pinch or cut the flower heads just below the base; the plant will keep blooming for several weeks if you harvest regularly. Once the weather turns hot — consistently above 80 degrees — the plant will set seed and die. You can delay this somewhat by deadheading spent flowers, but the plant's instinct is to finish its life cycle before summer arrives.

Left to itself, chamomile self-seeds prolifically. One plant can produce hundreds of seeds, and they germinate readily the following spring. Some gardeners consider this a benefit — a patch that re-establishes itself every year without replanting. Others find it invasive. If you want to keep chamomile in one place, deadhead the flowers before they go to seed, or pull the plants as soon as flowering slows. If you want it to spread, let a few plants go to seed in late spring and the volunteer seedlings will appear the following April.