Types and root length
Carrot is Daucus carota var. sativus (Delaware), a hardy biennial grown as an annual (UMD). The type sets how deep the soil has to be.
| Type | Root (UMD) | Notes |
|---|---|---|
| Round, stump-rooted, baby (Amsterdam) | 2–3 in long | Suited to heavy clay soil or containers (UMD) |
| Chantenay | 5–6 in long, 2–2½ in across the shoulder | Better for shallow, heavy soils than Imperator types (UMD); mainly for storage or processing (UW) |
| Nantes | 6–7 in, cylindrical, blunt tip | Small tops, dig carefully (UMD). Scarlet Nantes: 7 in, 70 days (Delaware) |
| Danvers | Conical, up to 7 in | Becomes fibrous with age (UMD). Danvers Half Long: 8 in, 75 days (Delaware) |
| Imperator | 7–8 in, 1½ in across | The main commercial fresh-market type; woody when fully mature (UMD). Recommended only for deep, sandy soil (Illinois) |
- 1. Round and baby (Amsterdam) types: 2–3 in long; suited to heavy clay or containers (UMD)
- 2. Chantenay: 5–6 in; better than Imperator for shallow, heavy soils (UMD)
- 3. Nantes: 6–7 in, blunt tip (UMD)
- 4. Danvers: conical, up to 7 in (UMD)
- 5. Imperator: 7–8 in; only for deep, sandy soil (Illinois)
- 6. Container depth: 8–12 in for UMD's medium class; NC State lists 10 in as the minimum and 10–12 in of mix as better
- 7. In the garden, prepare the soil 8–9 in deep (Illinois)
Soil depth and preparation
- Depth: prepare the soil 8–9 in deep so roots can develop fully (Illinois). Compaction layers restrict roots; commercial guidance is to break up a plow pan at 6–8 in (UW).
- Texture: loose, well-drained soil free of rocks, clods and debris (UMD); deep, sandy soil rich in organic matter, with compost and double digging for heavy soil (USU). Raised beds improve drainage and carrot shape (UW).
- pH: 6.0–6.8 (UMD) or 5.5–7.0 (UW).
- Sun: full sun; very light shade is tolerated (Delaware).
| Root problem | Causes named |
|---|---|
| Forked or twisted roots | Heavy soil (UW, USU); stones and clods (UW, Illinois); unrotted wood chips, root-knot nematodes, deep or close cultivation, thick seeding with poor thinning (Illinois); overwatering (USU) |
| Cracked roots | Wet weather after dry weather (UW, USU); excess moisture near harvest (UMD) |
| Short, blunt or pale roots | Warm temperatures (UW); above 70°F reduces root length (UMD); above 85°F, poor color (USU) |
| Green shoulders | Sun on exposed tops. Pull loose soil over the row 40–50 days after planting (Illinois) or hoe soil around the tops (UW) |
| Hairy, bitter roots | Aster yellows (UW, Illinois); see pests below |
Germination
| Question | Figures given |
|---|---|
| Minimum soil temperature | 40°F at 4 in, 8 a.m. (CSU); sow after soil reaches 40°F (USU); at least 45°F (UMD); "when soil warms to 60°F" (UNH) |
| Best germination | 55–65°F, reduced above 80°F (USU); optimum 80°F, maximum 90°F (CSU) |
| Days to emerge | 10–17 (CSU); 14–21 (USU); 1–3 weeks (UMD); up to two weeks, often unevenly (Illinois) |
| Seed depth | 1/4 in (CSU, UW, USU); 1/4–1/2 in (UMD); 1/4–1/2 in early, 1/2–3/4 in in later, warmer, drier soil (Illinois) |
| Spring sowing | As soon as the soil dries, or 0–2 weeks before the last frost (CSU); 2–3 weeks before it (USU); as soon as the soil can be worked (Illinois); around April 15 in southern Wisconsin (UW) |
| Fall crop | Plant 10–12 weeks before the first frost (UMD); 60–80 days to maturity in UNH's fall chart |
- Sow thinly. No more than 2–3 seeds per inch (Illinois). Pelleted seed is easier to handle but usually costs more (Illinois).
- Keep the surface moist. In dry weather water lightly each day until plants are established (UMD); water before germination to prevent a crust (UW).
- Prevent crusting. Heavy rain can pack the surface so that no seedlings emerge (Illinois). Cover seed with compost or fine sand (USU).
- Mark the row. Radish seed sown with carrots marks the row while carrots are slow to appear (UMD, USU, Illinois) and helps break crusts (USU).
- Warm or shade as needed. Clear plastic film warms early soil and holds moisture; remove it when seedlings appear. In midsummer, shade protects tiny seedlings (Illinois).
- Weed early. Carrots compete poorly while establishing (USU); cultivate shallowly so roots are not damaged (Illinois).
Find your frost dates on frost dates explained or count back with the planting calendar.
Thinning and spacing
| Source | When to thin | Final spacing | Rows |
|---|---|---|---|
| UMD | About 2 in tall; cut, don't pull | 1–4 in | — |
| USU | 3–4 true leaves | 2–3 in | 12–18 in |
| Illinois | About 1 in tall | Finger carrots up to 3 per inch; young harvest 1–2 per inch; Danvers and Chantenay 1 every 1–2 in | 12–18 in |
| CSU | — | 2–3 in each way in block beds, on soil with 4–5% organic matter | — |
| UF/IFAS, NC State | — | 16 per square foot, 3 in apart | Grid |
Compare other crops on square foot gardening spacing.
Containers
- Depth first: UMD puts carrots in its medium class, at least 4–6 gallons and 8–12 in deep. NC State's container table gives a minimum of 2 quarts and 10 in deep, with 10–12 in of mix preferred. See container sizes for vegetables.
- Short types: round or stump-rooted carrots suit containers (UMD). UW–Madison lists 'Danver's Half Long', 'Little Finger', 'Nantes Half Long', 'Paris Market' and 'Yaya' for containers.
- Spacing: 2–4 in apart so roots form properly (UW–Madison); thin to 2 in (NC State).
Water, temperature and harvest
- Best growth and flavor at 59–65°F (UW); best shape and quality at 55–75°F (UMD). Mulch and water in heat (USU).
- Even moisture reduces cracking (UW); ease up on watering near harvest (UMD).
- Harvest for fresh use before roots pass 1 in across, about 65–75 days (UMD); at 3/4 in, about 60–70 days, or 50–60 days for finger types (Illinois); 70–100 days from seeding (USU).
- Carrots take light frost (UNH). Summer plantings can stay in the ground until a killing frost, and straw or row cover extends harvest until the ground freezes (Illinois).
- Store at 32°F and 95% humidity (UW, USU) or 33°F (UMD); 4–6 months under proper conditions (Illinois). Keep carrots away from apples and pears, which make them bitter (USU).
Pests and diseases
| Problem | Signs | Extension guidance |
|---|---|---|
| Carrot rust fly | White maggots about 0.33 in long; tunnels near the root surface, nothing visible above ground (UC IPM) | Row cover over the seedbed; time planting to avoid egg-laying periods; harvest in blocks; do not leave carrots in the ground over winter; also attacks parsley and celery (UC IPM). Fabric row covers (USU) |
| Aster yellows | Yellowing, bunchy, twisted tops; woody or hairy, bitter roots (UW, Illinois) | Spread by the aster leafhopper; no cure (UW). Row cover excludes leafhoppers; tolerant cultivars; remove weeds at the edges (UW) |
| Leaf blights | Dark spots that enlarge (Alternaria) (UW) | Favored by long leaf wetness (USU); rotate 3 years for Alternaria, 2–3 years for Cercospora leaf blight (UW) |
| Carrot weevil, leafhoppers | Listed by Delaware | Ask your county extension office to confirm the pest |
This page gives no pesticide or fertilizer rates. Follow your soil test and any product label exactly, and ask your county extension office to identify problems.
Where sources disagree
| Question | Figures given |
|---|---|
| Soil temperature to sow | 40°F (CSU, USU) vs 45°F (UMD) vs 60°F (UNH) |
| Best germination temperature | 55–65°F (USU) vs optimum 80°F (CSU) |
| Days to emerge | 10–17 (CSU) vs 14–21 (USU) |
| Final spacing | 1–4 in (UMD) vs 2–3 in (USU, CSU) vs 2–4 in in containers (UW–Madison) |
| Container size | 4–6 gal, 8–12 in deep (UMD) vs 2 quarts, 10 in deep (NC State) |
| Days to harvest | 65–75 (UMD) vs 60–70 (Illinois) vs 70 (CSU) vs 70–100 (USU) |
| pH | 6.0–6.8 (UMD) vs 5.5–7.0 (UW) |
Small-space checklist
- Match the type to the depth: round or short types for shallow soil and pots, Imperator only in deep, sandy soil.
- Loosen the soil 8–9 in deep and remove stones and clods; use pots at least 10 in deep.
- Sow 1/4–1/2 in deep, thinly, with a few radish seeds to mark the row.
- Keep the surface moist and uncrusted for up to three weeks.
- Thin to 1–4 in by cutting seedlings; 16 per square foot in grid beds.
- Water evenly, hill soil over shoulders, harvest before roots turn woody.
More crop pages: radishes, kale, spinach, lettuce, tomatoes and peppers.
Sources
- University of Maryland Extension, Home and Garden Information Center — Growing Carrots
- University of Maryland Extension — Types of Containers for Growing Vegetables
- University of Wisconsin–Madison Extension — Growing Carrots, Beets, Radishes, and Other Root Crops in Wisconsin: A Guide for Fresh-Market Growers (A3686, Delahaut and Newenhouse, PDF)
- University of Wisconsin–Madison Extension — Growing Vegetables in Containers
- University of Wisconsin–Madison Extension — Vegetable Varieties for Containers (Vijai Pandian, revised 2021)
- University of New Hampshire Extension — Growing Vegetables: When to Plant Your Vegetable Garden (fact sheet)
- University of New Hampshire Extension — Fall Vegetable Gardening (Yard and Garden Infoline, 2020)
- Colorado State University Extension — Vegetable Planting Guide (CMG GardenNotes #720, reviewed 2024)
- Utah State University Extension — How to Grow Carrots in Your Garden (Dan Drost, 2020)
- University of Illinois Extension — Carrots (Home Vegetable Gardening)
- NC State Extension Gardener Handbook — Chapter 18, Plants Grown in Containers (Table 18-1)
- University of Delaware Cooperative Extension — Carrots (fact sheet, 2024)
- UC Statewide IPM Program — Carrot Rust Fly (Home and Landscape)
- UF/IFAS Gardening Solutions — Square Foot Gardening
- NC State Plants for Human Health Institute — Square Foot Seeds (PDF)
All sources were opened and checked in October 2026. Rules and figures change; confirm with the original before acting.