Dill gives you two products from one plant: dill weed, the early feathery foliage, and dill seed, harvested later from the dried flower heads. It is the most succession-dependent herb here, since an individual plant has only a 4 to 6 week window of productive foliage before it bolts. Its deep taproot means you must direct sow it rather than transplant. Plants reach 2 to 4 feet tall with umbrella-shaped yellow flowers that attract black swallowtail butterflies and other beneficial insects. Bouquet, at 24 inches, is a compact choice for containers; Mammoth, at 36 to 60 inches, is better for seed production. Key facts: 40–55 days to maturity, 6+ hours of sun, 12 " spacing. Container-friendly (minimum 2-gallon pot).
Updated June 1, 2026·Backed by 4 cited sources
Overview
At a Glance
The essentials first: timing, light, spacing, seed-starting, container fit, and overall size.
Days to maturity
40–55 days
Sun
6+ hours
6 8 Hours
Spacing
12 "
between plants
Container
Yes
2+ gallon pot
Height
2–4 ft
at maturity
Planting window
Zone Planting Guide
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Care
Growing Guide
Everything in one place: seed starting, transplant timing, watering, soil, and structural support.
Seed starting
Germination
Time10–14 days
Optimal temperature65°F
Seed depth0.25"
Moisture
Watering
Weekly1 "
NeedsModerate
Keep soil evenly moist during germination. Moderate moisture is sufficient once established.
A soil-borne fungus (*Sclerotium rolfsii*) that attacks plant stems right at the soil line during hot weather. It hits over 500 different plant species. Two telltale signs to look for: white fan-shaped fungal growth on the lower stem, mulch, and soil surface, and tan-brown spherical sclerotia (they look like mustard seeds) on infected tissue. Most active during sustained heat with humid conditions.
Triggers: Optimal at 86°F (30°C) soil and air temperature with humid conditions. Inactive below 70°F. Most damaging during sustained mid- to late-summer heat waves. It extends further north in warmer-than-normal seasons.
Risk fades when: Sustained cooler weather — highs below 80°F and overnight lows below 70°F for 5+ days — reduces fungal activity. The sclerotia (resting bodies) persist in soil for years, so resolution is seasonal, not curative.
A seedling killer caused by several different fungi working together. It hits vegetables, flowers, herbs, microgreens, and cover-crop seedlings the same way — seeds rot before they emerge, or young seedlings collapse right at the soil line. Wet seed-starting mix and poor airflow in seedling trays are the classic conditions.
Triggers: Wet soil or starting mix, poor drainage, seedlings packed too tightly, contaminated trays or media, and stagnant air all favor damping-off.
Risk fades when: Drying the soil surface and improving airflow slows new spread. Collapsed seedlings don't recover, but the rest of the tray can be saved.
Damping off of coffee seedlings caused by Fusarium sp. — Photo:
Scot Nelson
·
CC0 1.0
Aphids are soft-bodied sap-sucking insects that cluster on tender new growth. Most established plants tolerate moderate populations and will outgrow damage on their own, but aphids are the most important plant virus vectors in the garden, transmitting more than 100 plant viruses including potato leafroll, cucumber mosaic, and turnip mosaic. Honeydew excreted while feeding supports sooty mold growth and attracts ants that protect aphids from natural enemies.
Triggers: Optimal development at ~75°F (green peach aphid) per UC IPM Floriculture; melon aphid develops fastest above 75°F. Many species heat-intolerant above 90°F and crash in mid-summer. Soft new growth and over-fertilization with high N favor population buildup. Females give live birth parthenogenetically most of growing season — one generation in ~1 week under optimal conditions.
On Dill: Clusters on new growth.
Prevention: Water blast. Ladybugs. Dill's own flowers attract beneficial predators.
Risk fades when: Per UC IPM and Clemson HGIC, populations crash in mid-summer heat (>90°F) for many species, return in cooler conditions
BoltingHeat triggers rapid bolting. Long days + temps >80°F accelerate flowering.
Moderate
Physiological
No data
Heat triggers rapid bolting. Long days + temps >80°F accelerate flowering.
On Dill: Heat triggers rapid bolting. Long days + temps >80°F accelerate flowering.
Prevention: Succession planting. Skip midsummer sowing in zones 7a+. Afternoon shade helps slightly.
Powdery mildew (Apiaceae herbs)Erysiphe heraclei
Moderate
Disease
May–AugPeak window months: May, Jun, Jul, Aug.
A powdery mildew of carrot-family herbs such as dill, parsley, fennel, and cilantro. It coats leaves and stems with a white-to-gray powdery growth, and heavy infection yellows and weakens foliage and taints flavor. Unlike most leaf diseases it spreads in warm, dry weather with high humidity, and does not need leaf wetness.
Triggers: Powdery mildew thrives in warm, humid conditions and, unlike most fungi, does not require leaf wetness; rain actually suppresses it. Shade and crowding raise risk.
Risk fades when: Sustained heat above about 90°F slows powdery mildew. Two such days reduces active pressure; existing colonies remain on infected leaves.
Premature diebackPremature dieback covers a range of end-of-season behaviors. Annual herbs (basil, cilantro, dill) decline naturally as days shorten and temperatures cool — this is normal once flowering has happened.
Moderate
Physiological
Jul–SepPeak window months: Jul, Aug, Sep.
Premature dieback covers a range of end-of-season behaviors. Annual herbs (basil, cilantro, dill) decline naturally as days shorten and temperatures cool — this is normal once flowering has happened. Tender perennials in cold climates may die back to the ground when frost arrives. But premature dieback before its time can signal: cold snap below the plant's tolerance, root disease (Fusarium, Verticillium, Pythium), pest pressure (root-feeding larvae), or simply the plant having reached the natural end of its cycle. Annual basil typically dies after first frost; if basil dies in mid-summer, that's a sign to investigate. Tender perennial herbs in zone 5-6 die back annually and regrow from roots — that's normal. Distinguishing 'natural cycle complete' from 'plant has a problem' is about timing and visible symptoms.
Triggers: Most herb dieback is natural end-of-season. Mid-season dieback usually indicates root disease, pest damage, or severe drought stress. Investigate visible signs before assuming normal cycle.
Risk fades when: Natural dieback of annual herbs at season end is expected. Mid-season dieback warrants investigation: dig up the plant, check roots for rot/galls, examine stems for borer damage.
Scales are immobile sap-sucking insects under protective waxy or hardened covers. Soft scales produce sticky honeydew that supports sooty mold; armored scales cause direct dieback. They are primarily pests of woody plants and perennial herbs — fruit trees, berries, citrus, bay, rosemary — rather than annual vegetables. Females are sedentary as adults; the mobile 'crawler' stage that hatches in late spring/early summer is the target for control.
Triggers: Most species: one generation/year in north; multiple in south. Lecanium overwinters as 2nd-instar nymphs on twigs; crawlers emerge June-July. San Jose scale overwinters as 2nd instar on bark; crawlers May-June. Stressed plants more susceptible; ant attendance protects scales by deterring parasitic wasps.
Slugs and snails are nocturnal mollusks that chew irregular holes in leaves and clip off succulent seedlings. They leave characteristic silvery slime trails. Hermaphroditic and prolific, brown garden snails lay around 80 eggs per month for up to six clutches per year.
Triggers: Active at night and early morning in damp conditions. Coastal CA and southeast — active year-round. Spring rains and dense ground cover (mulch, debris, weeds) create harborage.
Risk fades when: UC IPM
Spider mitesTetranychus urticae (two-spotted spider mite, most common); also broad mite (Polyphagotarsonemus latus), russet mite (Eriophyidae)
Moderate
Pest
Jul–SepPeak window months: Jul, Aug, Sep.
Spider mites are tiny arachnids (1/50 inch) that feed on the undersides of leaves, producing characteristic silver-yellow stippling. Heavy populations produce visible webbing that interferes with pesticide coverage. They thrive in hot dry weather and drought-stressed plants. The two-spotted spider mite feeds on more than 180 cultivated plant species.
Triggers: Hot dry conditions; >90°F lifecycle <2 weeks. Drought stress amplifies. Broad-spectrum sprays (carbaryl, pyrethroids) trigger outbreaks by killing predators. Wisconsin Ext: 'as little as a month without significant rain during the growing season can favor a mite outbreak.'
Risk fades when: UMN Extension
ThripsFrankliniella occidentalis (western flower thrips), F. tritici (eastern flower thrips), F. fusca (tobacco thrips), Thrips tabaci (onion thrips)
Moderate
Pest
SpringPeak window months: Mar, Apr, May.
Thrips are tiny (1/16 inch) slender insects with fringed wings that puncture and rasp leaf surfaces, leaving silver stippling with black frass dots. The biggest concern is virus vectoring: western flower thrips is the principal vector of tomato spotted wilt virus (TSWV) and impatiens necrotic spot virus (INSV), which affect more than 600 plant species. Greenhouse and high tunnel infestations can be devastating.
Triggers: Hot dry weather; greenhouse/high tunnel environments. Female lays eggs inside leaf tissue. 2 larval stages feed; 2 non-feeding pupal stages in soil/litter. Lifecycle 10-21 days. Many overlapping generations. Bridge crops (spring wheat, peach, strawberry per NC State) build populations before vegetable hosts available.
Leafminers are tiny fly larvae that feed between the upper and lower surfaces of leaves, creating winding pale tunnels or blotchy patches. They rarely kill plants but can ruin the marketability of leafy greens grown for foliage. Allium leafminer is an emerging pest in the eastern US (first detected in Pennsylvania in 2017) that damages onions, garlic, leeks, and chives.
Triggers: Liriomyza trifolii: 1 generation in ~1 month at typical greenhouse temps, 14 days at 95°F, 64 days at 59°F (UC IPM). Adults active mid-day. Allium leafminer emerges late March-early April, second flight September-October. Broad-spectrum insecticides trigger outbreaks by killing parasitoids.
Risk fades when: UMD
Parsleyworm (eastern black swallowtail)Papilio polyxenes (eastern); Papilio zelicaon (anise swallowtail — western analog)
Low
Pest
May–JunPeak window months: May, Jun.
The parsleyworm is the larva of the eastern black swallowtail butterfly, a beneficial pollinator. Caterpillars feed on Apiaceae crops — parsley, dill, fennel, carrot, celery, parsnip — and can rapidly defoliate small plantings in their last instar. Most gardeners tolerate or relocate the caterpillars rather than control them, as they become important pollinators.
Triggers: Overwinters as chrysalis on tree bark or structures. Adults emerge May-June. 2-3 generations/year in NC. Eggs single on Apiaceae leaves; 10 days from hatch to pupation.
On Dill: Black swallowtail larvae. Same as parsley.
Prevention: Handpick and relocate. Plant extra as sacrifice host.
Risk fades when: NC State: 2-3 generations/year
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Feeding & picking
Nutrition & Harvest
How hungry the plant is, what ripe harvest looks like, and how long the crop keeps after picking.
Feeding
Nutrition
Feeding intensityLight feeder
Timing
Harvest
Storage7 days
Plant relationships
Companion Planting
Helpful neighbors can support growth or deter pests. Keep antagonistic plants separated to reduce stress and competition.
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What you'll need
Growing Supplies
Hand-picked for your Dill, with the extension research behind every recommendation.
Seed starting tray + heat mat
For gardeners who start seeds indoors, this combo improves even germination. Warm-season crops benefit from bottom heat. Look for a rigid tray, cell inserts with drainage, and a heat mat paired with a thermostat.
Source: Utah State University Extension; Iowa State University Extension; Mississippi State University Extension
Nearly every garden benefits from mulch for weed suppression, moisture conservation, and soil temperature moderation. For most home gardeners, quality organic mulch is the better buy over landscape fabric.
Source: Penn State Extension; Wisconsin Horticulture; Illinois Extension
Every gardener benefits from putting water at the root zone instead of on the leaves, because drip and soaker systems reduce foliar disease pressure by limiting leaf wetness and soil splash. A quality kit should include a backflow preventer, filter, pressure reducer, and UV-resistant tubing.
Source: Iowa State University Extension; Colorado State University Extension; UMass Extension
Row cover adds frost protection, speeds early growth, and physically excludes insect pests without spraying. Look for spun-bonded fabric with a stated weight and frost rating, UV resistance, and enough width for hoops or low tunnels.
Source: University of Maryland Extension; University of New Hampshire Extension; Colorado State University Extension
K-State Research and Extension and University of Maryland Extension recommend shade cloth as a heat-management tool for vegetable gardens, with 30 percent shade rating most effective for tomatoes, peppers, and fruiting crops, and 40 to 50 percent for protecting heat-sensitive greens during hot summer months. University of Delaware research found 30 percent black shade cloth tripled marketable yield for bell peppers compared to unshaded plants, and Purdue trials showed shade cloth reduced maximum daily temperatures by 8 to 10 degrees Fahrenheit. Choose knitted polyethylene with reinforced grommets every 18 to 24 inches, mount on hoops or a frame with open sides for airflow, and remove or vent during prolonged wet weather to avoid increased humidity in the canopy.
Source: K-State Research and Extension; University of Maryland Extension; University of Delaware Cooperative Extension; Purdue University Extension
Reflective plastic mulch (white-on-black or silver)
North Carolina State Extension reports that white-on-black plastic mulch can reduce soil temperature by 5 to 20 degrees Fahrenheit and silver mulch by about 6 degrees, the opposite effect of black mulch which warms soil. This makes reflective mulch the appropriate plasticulture choice for hot zones (especially Zone 9a desert and other high-heat low-humidity areas) where overheating limits warm-season crop performance more than cold soil. Silver mulch adds documented aphid and thrips repellency from the reflective surface. Use only with drip irrigation installed underneath, never use plastic mulch without irrigation, and reserve for late spring or early fall plantings where the surrounding heat is the primary stress.
Source: North Carolina State Extension; University of Arizona Cooperative Extension
A soil test gives a baseline for pH and nutrient status so gardeners can add only what the soil actually needs. Prioritize a mail-in or lab-affiliated kit whenever possible because extension guidance notes that laboratory testing is more accurate than instant readers.
Source: University of Maryland Extension; Purdue Extension; Montana State University Extension
University of Minnesota Extension recommends measuring soil temperature 2 to 4 inches below the surface to decide when warm-season crops can actually be planted, because air temperature and average frost dates do not reliably predict whether soil is warm enough for germination. A dedicated soil thermometer with a 4 to 6 inch stainless steel probe gives gardeners a deterministic reading instead of relying on the calendar alone, which matters most in zones with wide last-frost variability. Look for a waterproof stainless steel stem, a clearly marked vegetable-garden temperature range, and a readable analog or digital display at planting depth.
University of Arizona Cooperative Extension notes that most vegetables root in the top 12 to 24 inches of soil and that hot, dry periods require more frequent irrigation, but watering by habit often wets only the top inch while leaving the root zone dry. A dedicated soil moisture meter with a long probe gives gardeners a deterministic reading at root depth instead of guessing from surface appearance, which is most critical in low-rainfall desert zones (Zone 9a Phoenix) and in raised beds or containers that dry from the top down. Look for a single-purpose moisture meter (not a 3-in-1 or 4-in-1 combo, which trade accuracy for feature count) with a probe that reaches 8 to 12 inches and a clear analog or digital display.
Source: University of Arizona Cooperative Extension
UF/IFAS Extension and Texas A&M AgriLife Extension recommend securing or removing trellises, shade cloth, hoop covers, container plants, and lightweight raised-bed accessories before tropical storms and hurricanes, since loose garden items become projectiles in high winds. Most-relevant for Gulf Coast Zone 8b (Houston, Mobile, New Orleans), Florida Zone 9b (Miami, Tampa), and any coastal area within the Atlantic and Gulf hurricane corridors. Galvanized steel ground anchors resist rust in humid coastal soils, and screw-in spiral anchors hold significantly better than driven stakes in saturated soil during storm conditions. Use quick-release fasteners on shade cloth and trellises so they can be removed quickly when a storm watch is issued.
Extension guidance favors bypass designs because they make cleaner, closer cuts on living tissue than anvil types. Look for hardened steel blades that can be sharpened, a comfortable grip, and a cutting capacity matched to real home-garden stems.
Source: University of New Hampshire Extension; Iowa State University Extension; Purdue University Extension
Raised beds improve drainage, let gardeners control soil from day one, reduce compaction, and make gardening more accessible. A quality kit should use rot-resistant, food-safe materials and provide enough depth for productive rooting.
Source: Penn State Extension; University of Delaware Cooperative Extension; Illinois Extension
The most useful mix is three categories: a beginner guide, a reference manual for diagnosis and crop-by-crop lookup, and a soil science book. Look for region-aware editions, strong visuals, and evidence-based authorship.
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Research
Sources
Reference material and extension guidance used to build this growing guide.
university Utah State Extension, Dill in the Gardenuniversity Illinois Extension, Dilluniversity Florida IFAS, Dill Productionuniversity Purdue, Black Swallowtail
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