Born at the University of Massachusetts Amherst's historic Waltham Field Station around 1950, Waltham 29 broccoli represents New England's answer to reliable cool-season growing. This compact, cold-hardy variety produces classic blue-green heads measuring 4-8 inches across, typically ready for harvest in 75-89 days depending on conditions. Standing 24-30 inches tall in zones 3-10, these sturdy plants excel in the cooler climates of the American Northeast and Pacific Northwest, delivering both substantial main heads and generous side shoot production that extends your harvest well into fall.
Photo © True Leaf Market
Growing Conditions
USDA Zone
3-10
Sunlight
Full Sun
Water
Moderate
Soil
Well-drained, Fertile Loam With Consistent Moisture
Preferred Temp60-75°F
Growth Stats
30 in
Height
—
Width
18 in
Spacing
75–80
Days to Harvest
PeriodAnnual
TypeBush
Plant Profile
Sunlight
Full Sun
Water
Moderate
Zones
3-10
Size
30in H x ?in W
Growth
Annual
Care
High
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Highlights
What sets Waltham 29 apart is its remarkable cold tolerance and reliable performance in challenging northern climates. Bred specifically for New England's unpredictable weather, this variety delivers uniform, high-yielding harvests when other broccoli varieties falter. The compact plants produce impressive 4-8 inch heads followed by abundant side shoots that keep producing after the main harvest, making it exceptionally valuable for both home gardens and farmers markets. Its natural resilience to frost means you can push the season later than most varieties, often harvesting well into fall when light frosts actually improve the flavor.
Common Uses
The entire plant offers culinary versatility, with tender leaves perfect for soups, firm heads excellent for steaming as a side dish or serving raw with dips and hummus, and even the flowers edible once the plant bolts. The main heads freeze exceptionally well, making this variety particularly valuable for preserving the harvest. The abundant side shoots that follow the main harvest provide fresh broccoli for weeks, perfect for stir-fries, pasta dishes, and quick sautés throughout the extended harvest season.
Growing Timeline
First Bloom
Does Not Bloom As Broccoli Is Harvested Before Flowering
First Harvest
Mid-summer
Last Harvest
Early Winter
Care Instructions
Start Indoors
Start seeds indoors 5-6 weeks before the last expected frost date in spring, or in midsummer for fall harvest. Plant seeds 1/4 to 1/2 inch deep with ideal germination temperature of 70-85°F, though seeds will germinate at soil temperatures as low as 40°F.
Transplant Outdoors
Transplant hardened-off seedlings when they are strong enough, after the last frost date for spring planting or 10-12 weeks before first fall frost for autumn harvest. Space transplants 18 inches apart in rows 30 inches apart.
Direct Sow
Direct sow seeds 4-6 weeks before the last frost when soil temperature reaches at least 40°F, spacing seeds 4 inches apart initially.
Harvesting
Harvest when heads are firm, tight, and measure 5-6 inches in diameter, typically 75-89 days from sowing. Cut the main head with several inches of stem attached using a sharp knife, removing it above the smaller florets. This encourages the development of side shoots that will continue producing smaller heads for weeks after the main harvest. Harvest promptly once heads reach full size, as they will become bitter and inedible if allowed to flower and lose their compact form.
Growing Calendar
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Companion Planting
Ecology & Traits
Edible
Scientific Classification
Brassica oleracea L. var. botrytis L.
Family
Brassicaceae
Genus
Brassica
Duration
Annual
Growth Habit
Upright
Native Status
L48 (I)PR (I)CAN (W)GL (W)
History & Origin
“Developed around 1950 at the University of Massachusetts Amherst's historic Waltham Field Station, this variety emerged from dedicated breeding work focused on creating broccoli that could thrive in New England's challenging climate. The researchers at Waltham Field Station cultivated this variety specifically to deliver higher yields, more uniform crops, and better repeat harvests than existing varieties of the time. Since its introduction in 1954, Waltham 29 has become a beloved staple variety, earning its place as a favorite on seed farms and proving its worth across decades of northern growing seasons.”