Once the summer solstice passes in late June, dill or cilantro become much less likely to burst into premature bloom.
Q: I made the beginner’s mistake of planting dill and cilantro as purchased seedlings, ending up with plants too spindly to produce a harvest. So last year I sowed seed right in my garden. The direct-seeded plants grew better, but they still started flowering when they were very small. What can I do to grow bushier plants?
A: Both dill (Anethum graveolens) and cilantro (Coriandrum sativum) are cool-season annuals with fragile taproots, so sowing seeds in spring is a sound practice. But to get a steady supply of either of these herbs, you will need to tuck a second set of seeds into the soil a month after the first, followed by a third planting in late summer.
The “some now, some later” planting strategy is called succession sowing, and it’s necessary because dill and cilantro are so easily excited by the weather changes of spring. When days get warmer, nights get shorter and daylight intensifies, dill and cilantro take note. They pay close attention to lengthening days, the strongest cue that summer is coming. The plants rush to fulfill their destiny, which is to produce a good crop of seeds.
Bolting is a success story from the plants’ point of view, but gardeners would like to slow the action. Making a second sowing helps, because seedlings sown in late May or early June are exposed to lengthening days for only a few weeks, when they are too young to care about reproductive matters. Once the summer solstice passes in late June and day length holds steady, dill or cilantro become much less likely to burst into premature bloom. More importantly, seedlings that break ground after spring has lost its chill are never exposed to the biggest flowering trigger of all—cold, cloudy conditions followed by plenty of warm sun.
Late spring plantings are less successful in warm climates where summer heat makes life unbearable for cool-natured plants. If you live where summers are long and hot, wait until fall to make a second sowing.
In the case of dill, the appearance of yellow flower umbels is not such a bad thing. With most herbs, the essential oil content of the leaves declines when blooming begins, but ferny dill foliage becomes more flavorful after the first flowers emerge. True ornamental edibles such as ‘Bouquet’ or ‘Vierling’ provide plenty of cut flowers for bouquets as well as tasty leaves. The tastiest leaves of all come from dark green ‘Dukat’ or ‘Superdukat’, or you can grow slow-bolting ‘Fernleaf’, a dwarf at only 18 inches.
Dill blossoms appear over a period of several weeks, and they make great garnishes for salads or vegetables. Also take advantage of dill’s immature green seed pods, which pack a delicious punch when stirred into hot pasta or risotto at the last minute, or sprinkled over any type of fish. As for the mature seeds, dill will reseed itself for fall if mature seeds are allowed to find their own places in the garden, with plenty more to gather and dry for making pickles or bread. The easiest way to gather ripe seeds from dill or cilantro is to wait until the seeds turn tan, and snip the clusters into a clean paper bag. Kept in a warm, dry place, the seeds will be ready to sort and store within a week.
Cilantro’s transition to maturity takes a toll on the flavor and texture of the leaves, and the first white flowers often are accompanied by a “buggy” aroma. The good news? Compared with dill, cilantro is more bolt-resistant to start with, and slow-bolting varieties such as ‘Santo’ (also called ‘Slow Bolt’) or ‘Jantar’ stay leafy longer before stretching into flowering mode.
For cilantro, flowering and setting seeds is the gateway to a becoming the spice known as coriander. The plant’s dual identity as a parsley-like green (cilantro) and a big-flavor seed (coriander) is rooted in culinary history. In its areas of origin—North Africa and the Eastern Mediterranean region—this herb is valued primarily as a seed spice. As the plant spread to the Far East and South America, cilantro foliage emerged as a hugely popular green herb. In your garden, you will have to wait several weeks between the time you stop gathering leaves and start snacking on toasted coriander seeds, but both forms of this versatile herb are delicious and useful.
Barbara Pleasant is a contributing editor to The Herb Companion and author of several books about gardening, including The Whole Herb (Square One, 2004). She lives in Pisgah Forest, North Carolina.
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