Dill (Anethum graveolens) is an essential herb for any culinary-minded home gardener. It belongs to the carrot family, making it a close relative of fellow members like celery and parsley.
In addition to its many uses in the kitchen, dill is a popular choice for cottage and pollinator gardens. It attracts a range of beneficial insects, including those that control pests around the park, and acts as a host for the Eastern black swallowtail caterpillar.
This article dives deep into six dill plant growth stages and the average days to complete each one.
Conditions for Growing Dill
Many sources classify dill as an annual herb. While dill is commonly grown annually, it’s technically a biennial. The plant usually takes two years to complete its entire life cycle.
Dill is well-suited to growing in USDA Zones 2 through 11. However, the herb is cold-hardy down to about 25°F, so it will only survive winters in Zones 9 and warmer.
If you want to ‘force’ dill to behave as an annual (this is important if you want to produce seeds in the first year), I recommend starting the dill in early spring. This exposes the plants to cool temperatures early on and helps trigger flowering and seed production later in the growing season.
As far as the day-to-day requirements of dill are concerned, it’s a reasonably low-maintenance herb. It enjoys full sun and daytime temperatures between 50 and 80°F. Planting your dill somewhere with afternoon shade can help boost its heat tolerance during the warmer months.
Dill needs moist, well-draining soil and is not very drought-tolerant. Mud that dries out completely between waterings will stress the plant, resulting in lower-quality leaves and premature flowering (bolting).
Since dill readily self-seeds itself, be mindful of where you choose to plant it in your garden. Select a site you won’t mind having dill reappear next year (and perhaps for several years).
I typically don’t suggest fertilizing dill in the home garden if the soil contains some organic matter. Any dirt that regularly produces other herbs and vegetables will have no trouble supporting a hearty crop of dill!
Dill Growth Rate
Dill wastes no time once well-established. Plants can grow 3 to 5 inches per week in ideal conditions (i.e., with adequate water, moderately cool temperatures, and at least 6 hours of sun daily).
Large dill plants can grow 3 to 5 feet tall and 2 to 3 feet wide. Dill should be spaced 12 to 24 inches apart so it has room to spread out. If you’re short on space, consider planting a dwarf variety like ‘Fernleaf’, which only grows about 18 inches tall.
The 6 Growth Stages of Dill
You can expect to start harvesting dill 28 to 56 days after planting from seed. Plants started from nursery transplants can produce even faster.
There are dozens of different dill varieties on the market. Gardeners can choose from varieties with unique traits like mature size or leaf shape. Overall, though, these plants all follow the same sequence of growth stages.
1. Seed Germination
Dill is most commonly started directly from seed. The seeds germinate quickly with the proper mix of warm temperatures, moisture, and light.
Seed germination takes 10 to 14 days in soil temperatures between 60 to 70°F. Germination can take up to 21 days in less optimal conditions.
As I noted above, dill seeds require light exposure to sprout. This means the sources must be very close to the soil’s surface (or sprinkled on top) for the best results. The earth also needs to be moist.
Germination begins as the dill seed absorbs moisture from the soil through the seed coat — a process known as imbibing. This moisture, in turn, triggers cell division within the source, and the tiny plant inside begins to grow.
The first part of the plant to sprout is the radicle. This is the seedling’s primary root and will eventually turn into the plant’s tap root. Next are the hypocotyl, the main stem, and cotyledons, the seedling’s very first leaves.
2. Seedling Emergence
While germination marks a significant transformation for the dill seed, things above the soil are uneventful until the hypocotyl and cotyledons emerge. The dill plant is now a seedling.
It’s common for a seedling’s cotyledons to look almost nothing like the plant’s mature leaves. This is especially true of dill. So don’t be alarmed by the seedling’s appearance when it first breaks through the soil.
The cotyledons develop in the seed embryo and hold valuable energy. This energy supports the seedling’s growth until it gets its true leaves and can begin proper photosynthesis. It may take another seven days or more for those true leaves to appear.
3. Vegetative Growth
Now the dill plant is ready to put all of its time and energy into producing strong growth both above and below ground. This stage typically continues for up to 56 days after germination.
New leaves will rapidly develop from the top of the stem. You might also notice the main stem branching out. The taller and bushier a dill plant gets generally equals a bigger harvest throughout the growing season.
Dill’s root system is mainly made up of a large tap root. This root grows surprisingly fast and can easily reach 8 to 2 inches in length, so care must be taken when transplanting young dill plants (it’s best to avoid transplanting dill altogether).
4. Flowering
Dill flowers in response to warm temperatures. It usually starts flowering about 56 days (or eight weeks) after sprouting and lasts 28 days or more. However, whilst it is a fantastic companion plant for many plants including brassicas and alliums, the conditions need to be just so as unseasonably hot weather can trigger early flowering in some cases.
The flowers are umbels borne on tall stems, similar to those of a carrot plant. Each umbrella-shaped flower contains numerous small florets. Dill flowers are typically light yellow and quite fragrant.
5. Pollination
Pollinating insects are highly attracted to dill flowers, so pollination is rarely an issue.
Dill is self-fertile, so you only need one plant to produce seeds. However, cross-pollination between multiple plants will have greater genetic diversity in the next generation.
I’ve heard from several sources that fennel can cross-pollinate dill and interfere with the latter’s flavour. However, these plants are in different genera, so this is most likely just a garden myth. Still, many gardeners keep fennel far away from their dill plants to be safe.
6. Seed Development
Pollinated dill flowers will eventually turn into seed heads. Most seeds are mature and ready to harvest about 90 days from germination.
You can leave these mature seeds to fall from the plant and self-sow in your garden naturally. Alternatively, the University of Minnesota says you can wait until just before the seeds dry out to clip off the top of the dill stem and save the seeds for planting in future years.
When to Harvest Dill
Herbs like dill are relatively easy to harvest. You just need to wait until the leaves are fully formed, and you can begin taking sprigs to use in the kitchen.
A good rule of thumb is to start harvesting after the dill plant is at least 6 inches tall and has four leaves or more. Avoid removing more than one-third of the plant at a time when harvesting- as with any herb.
Following the guidelines above, your dill will continue producing for several weeks or more. You can extend the season even further by staggering when you start dill seeds by a week or two.
Dill leaves can be harvested at any point once they’re big enough. However, experienced gardeners know that the best dill is harvested just before the plant starts to flower. After flowering, the dill leaves are still usable but may have a slightly different flavour profile. Keep all of this in mind to get the most from your annual dill crop!
FAQ Dill Plant Growth Stages
How long does it take dill to fully grow?
It’s common for dill to mature and be ready for harvest within just 28 days (or four weeks) of planting. However, the highest-quality herb is typically produced just before the flowers open. For most dill, this is about 56 days (or eight weeks) after planting.
Does Dill come back every year?
Dill is classified as an annual or biennial plant, which means each plant only lives for one to two years. The good news is that dill readily self-sows. So you can continue growing dill year after year using the seeds of the previous year’s crop.
Should you let Dill go to Flower?
Flowering dill can do a ton of great things for the garden. It attracts numerous pollinators like butterflies, bees, and more. The flowers also produce seeds for the next generation of dill. Plus, some people harvest the flowers themselves and use them as garnishes!
Citations
- University of Minnesota Harvesting dill seeds
Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.
