How to Grow Broccoli USA

On this page
  1. Broccoli (Calabrese) (Brassica oleracea Italica Group)
  2. Regional Planting Calendar
  3. Quick Facts
  4. At a Glance
  5. Soil & Growing Conditions
  6. Growth Stages
  7. Harvest & Storage
  8. Diseases
  9. Pests
  10. Nutrient Issues
  11. Companion Planting
  12. Plan your Broccoli planting
  13. Growing Broccoli (Calabrese) in another region
  14. Sources
  15. Frequently Asked Questions

In the US, broccoli planted out mid January, and is ready to harvest 50–90 days after planting out.

Timing is the decision that matters most in the USA: there are 7 separate regional planting out windows, ranging from mid January in Deep South & Gulf Coast to mid April in Intermountain West.

The short answer

Plant out
Mid January
Ready in
50–90 days after planting out
Site
soil pH 6.8–7.5
Biggest risk
White blister

Core growing advice on this page is checked against named horticultural sources — see References.

Broccoli (Calabrese) (Brassica oleracea Italica Group)

Calabrese broccoli head forming at the centre of the plant among broad blue-green leaves. Photo: Fungus Guy, CC BY-SA 3.0, via Wikimedia Commons.

12 sources cited · Verified

Regional Planting Calendar

Region Plant out
Deep South & Gulf Coast derived mid January
Pacific Northwest derived mid February to late February
Mid-Atlantic & Upper South derived mid March to late March
Northeast & New England derived mid March to late March
Lower Midwest & Ohio Valley derived late March to early April
N. Plains & Upper Midwest derived early April to mid April
Intermountain West derived mid April to late April

Rows marked derived are interpolated between regions our sources do state, because no source we consulted gives a figure for that region specifically. They are deliberately wider to reflect that uncertainty.

Deep South & Gulf Coast - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplants of 4-6 mature leaves may be planted 2-3 weeks before the last frost free date. Applied to a mean last frost of 2 February (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 12 January to 19 January. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Pacific Northwest - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplants of 4-6 mature leaves may be planted 2-3 weeks before the last frost free date. Applied to a mean last frost of 8 March (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 15 February to 22 February. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Mid-Atlantic & Upper South - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplants of 4-6 mature leaves may be planted 2-3 weeks before the last frost free date. Applied to a mean last frost of 4 April (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 14 March to 21 March. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Northeast & New England - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplants of 4-6 mature leaves may be planted 2-3 weeks before the last frost free date. Applied to a mean last frost of 6 April (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 16 March to 23 March. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Lower Midwest & Ohio Valley - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplants of 4-6 mature leaves may be planted 2-3 weeks before the last frost free date. Applied to a mean last frost of 16 April (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 26 March to 2 April. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

N. Plains & Upper Midwest - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplants of 4-6 mature leaves may be planted 2-3 weeks before the last frost free date. Applied to a mean last frost of 25 April (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 4 April to 11 April. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Intermountain West - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplants of 4-6 mature leaves may be planted 2-3 weeks before the last frost free date. Applied to a mean last frost of 6 May (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 15 April to 22 April. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Quick Facts

Factor Value
Soil pH 6.8 - 7.5
Optimal growing temp 59-75°F (15-24°C)
Minimum survivable temp 23°F (-5°C)
Time to harvest 50-90 days after planting out
Drainage RHS: firm, fertile, well-drained soil in full sun.
Lifecycle Annual.
Edible parts flower heads, stems

At a Glance

Brassica oleracea Itali… Broccoli (Calabrese) White blister Club root Damping-off (seedling c… Alternaria leaf blight Downy mildew (general) Black rot of brassicas Cabbage caterpillars Slugs Flea beetles Mealy cabbage aphid Cabbage root fly (US: c… Harlequin bug Imported cabbageworm Cabbage looper Cabbage webworm Cross-striped cabbagewo… Diamondback moth caterp… DISEASES PESTS

Soil & Growing Conditions

A small broccoli head forming at the centre of a young plant surrounded by large leaves — “Brassica oleracea var. italica (2276097250)” by Dinesh Valke is licensed under CC BY-SA 2.0. Source: Wikimedia Commons
“Brassica oleracea var. italica (2276097250)” by Dinesh Valke is licensed under CC BY-SA 2.0. Source: Wikimedia Commons.

Soil pH range

6.8 7.5

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Growth Stages

Stage BBCH Notes
Germination & seedling 0 Calabrese is raised from seed sown about 1–2cm deep, either in modules/pots or in situ where it is to grow — RHS notes calabrese resents root disturbance, so many gardeners sow direct or transplant while plants are still small. Seed germinates within about a week in warm soil (Clemson HGIC). Grow on to roughly 4–6 true leaves before planting out, and harden off module-raised plants first.
Vegetative growth (transplanting & leafing) 3 Plant or thin to about 30–45cm apart each way (RHS) — roughly 18in between plants (Clemson HGIC) — into firm, fertile, well-drained soil in full sun. Firm planting matters: loose soil gives poor, loose heads. Water in well, keep weed-free, feed with nitrogen for strong leafy growth, and net or fleece against pigeons and cabbage white caterpillars.
Head formation (curd/heading) 4 The central growing point forms a single domed head of tightly packed green flower buds. Steady, even moisture is critical now: RHS and Clemson HGIC both note that heat or water stress causes small heads, premature "buttoning", or bolting straight to flower. Keep plants consistently moist and mulch to hold soil moisture.
Harvest & side-shoots 8 Cut the main head while the buds are still tight and closed, before any yellow shows, when it is about 10–15cm across (RHS) — usually 50–90 days after sowing. Leave the plant in place: most calabrese varieties then produce smaller side-shoots from the leaf axils that crop for several more weeks.

Harvest & Storage

Freshly harvested broccoli head cut with a length of stem — “Broccoli crown from San Francisco farmers market” by HaJunkiyada is licensed under CC BY-SA 4.0. Source: Wikimedia Commons
“Broccoli crown from San Francisco farmers market” by HaJunkiyada is licensed under CC BY-SA 4.0. Source: Wikimedia Commons.

When to pick: Cut the main head when 10-15cm across, well formed but still in bud, before flowers begin to open; side-shoots then produce further smaller heads for several weeks

Diseases

White blister

Albugo candida

RHS calabrese guide names white blister among named problems.

Plasmodiophora brassicae

Damping-off (seedling collapse)
medium

Rhizoctonia solani

Damping-off (seedling collapse at soil line); Wilting with chlorotic, dropping leaves

Seed that rots before emergence, or seedlings collapsing at the soil line. A transplant-raising problem more than a bed problem: use fresh commercial mix, containers cleaned with a 10% bleach solution, and…

Alternaria leaf blight
medium

Alternaria dauci

Brown circular spots with concentric target rings, and small dark stem lesions on seedlings. Active between 60 and 90°F in moist conditions and overwinters on crop residue, so clearing the bed at season end plus a…

Downy mildew (general)
medium

Grey mould on the underside of the leaf with yellowing, later browning, on the upper surface directly above it. A moisture problem rather than a heat one: space widely so leaves dry, and water at soil level.

Black rot of brassicas
high

Xanthomonas campestris pv. campestris

Yellow V-shaped lesions cutting in from the leaf margin, with the point of the V aimed at a vein; the veins blacken and the rot can reach the stem. Seed- and transplant-borne, so it usually arrives on bought plants…

Pests

Cabbage caterpillars

Pieris brassicae; Pieris rapae; Pieris napi; Mamestra brassicae; Plutella xylostella

Slugs

Gastropoda (slugs, various spp.)

Flea beetles

Chrysomelidae: Alticini (various spp.)

RHS calabrese guide names flea beetles on brassicas among named pests.

Mealy cabbage aphid

Brevicoryne brassicae

RHS calabrese guide names mealy cabbage aphid among named pests.

Cabbage root fly (US: cabbage maggot)

Delia radicum

RHS calabrese guide names cabbage root fly among named pests.

Harlequin bug
medium

Murgantia histrionica

A shield bug with a striking reddish-orange and black pattern; the eggs look like tiny black-and-white striped barrels laid in rows, which makes them easy to find and destroy. Piercing-sucking feeding leaves distinct…

Imported cabbageworm
medium

Pieris rapae

About an inch long and recognisable by its fuzzy appearance; Clemson rates it at about two-thirds the damage of a looper. It pupates in a chrysalis on the host plant, so it can be removed with the plant.

Cabbage looper
high

Trichoplusia ni

Up to 1.5 inches, moving in the distinctive looping gait, and it makes far bigger holes than diamondback moth -- Clemson puts one looper at roughly the damage of five diamondback larvae, so finding one matters more.…

Cabbage webworm
medium

Hellula rogatalis

Small, tan and brown striped with a dark head. It webs itself into the new growth for protection and attacks the buds and growing point, which causes lateral budding and can ruin a plant that would otherwise have made…

Cross-striped cabbageworm
medium

Evergestis rimosalis

Alternating black and white stripes across the back with a yellow stripe along the side, reaching about three-quarters of an inch. It hatches in masses and can rapidly skeletonise a plant, then drops to pupate just…

Diamondback moth caterpillar
high

Plutella xylostella

Clemson calls it "the most serious insect pest of brassica crops in South Carolina" despite being small, up to half an inch. The tell is a window-pane effect: the caterpillar eats the underside and leaves the upper…

Nutrient Issues

Boron (B)

deficiency

Correction

RHS names calabrese among the boron-sensitive vegetables, with hollow stem and browning heads as the symptoms. Boron is less available above pH 7, so avoid liming already-alkaline ground. Test soil pH rather than adding boron blind -- the margin between deficiency and toxicity is narrow.

Companion Planting

avoid shared disease

Brassica oleracea Gemmifera Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Brassica napus Napobrassica Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Raphanus sativus

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Brassica oleracea Acephala Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Brassica oleracea Botrytis Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Brassica rapa Rapifera Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Brassica oleracea Capitata Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

Plan your Broccoli planting

When to sow and plant Broccoli depends on your own frost dates. Check the USA vegetable planting calendar, or the month-by-month guides that cover Broccoli: July, October, November. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.

Growing Broccoli (Calabrese) in another region

Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.

Sources

  2. Black rot shows yellow V-shaped lesions with the point of the V directed toward a vein, favoured by high temperature and humidity, surviving on debris up to two years when buried plus on wild mustard and contaminated seed; avoid cole crops where it occurred within two to three years and do not handle wet plants. Downy mildew is grey mould on the lower leaf surface with yellowing above. Alternaria leaf spot makes brown circular target spots with concentric rings between 60 and 90°F, overwintering on residue, calling for three-year rotation. Pythium damping-off rots seedlings at the soil line.

  3. Diamondback moth is "the most serious insect pest of brassica crops in South Carolina", leaving a window-pane appearance where the upper leaf surface stays intact. Damage is quantified relative to each other: one cabbage looper does roughly the damage of 5 diamondback moth larvae, and imported cabbageworm about two-thirds of a looper. Cross-striped cabbageworm hatches in masses and can rapidly skeletonise a plant, dropping to pupate just under the soil surface. Cabbage webworm damages buds and growing points, causing lateral budding. Cabbage aphids are commoner in cool autumn weather. Flea beetles are most problematic on mustard and turnips, which lack the protective waxy coating.

  4. Transplant vigorous young plants in early spring; for autumn crops start seedlings in midsummer and transplant in late summer, counting back from first frost and adding 10 days to the days-to-harvest figure. Sow seed 1/4 to 1/2in deep. Space transplants 18-24in apart in rows 36in apart, or 1ft apart each way in beds. Use a starter fertiliser at transplanting and side-dress with nitrogen at half mature size. Provide ample soil moisture, especially as the heads develop. HARVEST: cut the central head with 5-6in of stem once fully developed but BEFORE it loosens, separates and the individual flowers start to open and show bright yellow; central heads reach 4-6in across, and side shoots develop after the main head is removed. Pests: aphids colonising leaf undersides, and three cabbage worms -- imported cabbage worm, cabbage looper and diamondback moth.

  5. Transplants of 4-6 mature leaves may be planted 2-3 weeks before the last frost-free date; 12-18 in between plants with rows 2-3 ft apart; cultivars 50-65 days; highest yields where temperatures do not exceed 75°F, not seriously damaged down to 28°F; buttoning follows cold exposure or water/nutrient stress before or after transplanting; hollow discoloured stem with brown spotting on the head indicates boron deficiency; cut heads compact before the flower buds open at 6-12 in across; with extra water and feed the plant makes many 3-6 in side shoots; stores 1-2 weeks at 32°F and 95% relative humidity.

These 5 sources are specific to this region. The full list of 12 sources behind this guide (Clemson Cooperative Extension, FAO EcoCrop, Royal Horticultural Society and others) is in the references of our UK guide to broccoli; they describe the plant itself, which is the same wherever it grows.

Frequently Asked Questions

When should I plant broccoli out in the USA?

In Deep South & Gulf Coast, from mid January. In Intermountain West, wait until mid April. Treat these as a guide rather than a fixed date — the governing rule is to plant out only once frost risk has passed and temperatures are reliably warm enough.

How long does broccoli take to grow?

Typically 50–90 days after planting out, depending on cultivar and growing conditions.

What soil pH does broccoli need?

A pH of about 6.8–7.5. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.

What problems affect broccoli?

Our data links 6 diseases and 11 pests to this crop. See the sections above for each one and how to manage it.

Plan next season before the problems start

Almost everything on this page resolves to your own frost dates rather than the calendar — the last spring frost moves by roughly two months between zone 3 and zone 10. The USA Garden Planner works from your zone so the timing is already decided before the season starts.

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SoilCommander Editorial Team — under the direction of Nitin Sharma, Co-Founder

Every growing guide is checked against RHS, USDA Cooperative Extension, and other named horticultural authorities before publishing.

How this guide is put together

The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against USDA hardiness-zone and frost-date data, with Cooperative Extension sources cited directly where one exists for a crop. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.

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