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Mammoth Dill is a tall, vigorous annual herb that lives up to its name, reaching 36 to 48 inches with impressive lacy foliage and beautiful yellow umbel-shaped flowers. This heirloom, open-pollinated variety produces aromatic leaves with robust flavor in just 60 to 69 days, making it reliable for both fresh harvests and seed collection. Grow it in full sun with moderate water and neutral soil (pH 6.0 to 7.0), and you'll have garden-fresh dill perfect for pickling, garnishing, and culinary use from summer through fall.
Full Sun
Moderate
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48in H x ?in W
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Moderate
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The lacy, pale gray-green foliage of Mammoth Dill is as ornamental as it is flavorful, with yellow flowers that deserve a place in cut flower arrangements. Its vigor and impressive size mean abundant harvests of both tender leaves and seeds, and at 18 inches between plants, you can fit several into a compact space. Unlike smaller dill varieties, this cultivar's robust growth and hearty nature virtually guarantee success for gardeners seeking serious yields without fussiness.
Mammoth Dill's tender leaves are perfect for garnishing cold summer soups, cucumber salads, and freshly baked fish. The abundant foliage works fresh in salads and as a delicate herb for finishes on roasted vegetables and seafood. Its robust seed production makes it excellent for pickling, where both the seed heads and young plants are harvested for dill pickles. The flowers add visual interest to fresh arrangements and can be dried for later use.
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Start seeds indoors 4 to 6 weeks before your last spring frost, keeping soil at 60 to 70 degrees Fahrenheit. Dill germinates quickly and does not require light to sprout; cover seeds lightly with soil or vermiculite. Seedlings emerge in 7 to 10 days. Transplant to the garden once they've developed true leaves and can handle outdoor conditions.
Harden off seedlings over 7 to 10 days by gradually exposing them to outdoor conditions. Transplant into the garden after the last frost date when soil has warmed to at least 60 degrees Fahrenheit. Space plants 18 inches apart in rows 24 inches apart. Dill transplants can be tender; handle gently to avoid root disturbance.
Direct sow seeds outdoors 2 to 3 weeks before your last spring frost, as Mammoth Dill is frost-tolerant and germinates best in cool soil. Sow seeds where you want them to grow, since dill does not transplant well from direct sowing. Succession sow every 2 to 3 weeks for continuous harvests through the season.
Begin harvesting tender leaves as soon as the plant reaches 8 to 10 inches tall, typically 30 to 40 days after sowing. Pinch or cut the feathery foliage from the top of the plant, encouraging bushier growth and continued leaf production. For seed harvest, allow the flowers to mature and dry on the plant; once the seed heads turn brown and papery, usually 60 to 69 days from sowing, cut the entire seed head and dry it upside down in a paper bag to catch falling seeds. Fresh leaves are best used immediately or refrigerated in a plastic bag for up to a week.
Mammoth Dill's upright growth habit does not require extensive pruning, but pinching off flower buds early in the season encourages the plant to produce more tender foliage. Once you decide to let the plant flower for seed production, remove flowers as they fade to extend the harvest window. Allow the final flowers to mature fully if you're collecting seeds for next year's garden.
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“Mammoth Dill is an open-pollinated heirloom variety, preserved through generations of seed savers who valued its exceptional size and vigor. As a heritage cultivar of Anethum graveolens, it represents the dill that home gardeners and small farms have relied on for decades, chosen specifically for its ability to produce abundant foliage and seed in a single season. Its presence in modern seed catalogs reflects both its proven performance in gardens and the ongoing commitment of seed companies and heirloom enthusiasts to keep this reliable variety available.”