Waltham 29, Broccoli Seeds

Waltham 29 Broccoli Seed

Cold-tolerant heirloom produces generous blue-green central heads
Six-to-eight-inch crowns rise on sturdy, adaptable plants
Strong side-shoot production extends harvest after the main head
Especially dependable for productive fall broccoli crops

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Key Attributes

Botanical Name

Brassica oleracea

Days to maturity

80 Days

Sun

Full Sun

Packet

200 Seeds

About Waltham 29, Broccoli Seed, Broccoli Seed

Waltham 29 broccoli seeds produce a classic, open-pollinated variety that was developed in the early 20th century by the University of Massachusetts at Waltham and has remained a trusted garden standard ever since. This variety forms large, deep blue-green central heads measuring 6–8" across on sturdy, cold-tolerant plants that typically reach 20–24" tall. The tightly packed florets have a tender texture and mild, slightly sweet flavor, excellent for fresh eating, steaming, freezing, and a wide range of culinary uses.

Growing details

Planting

Sow Depth

1/4"

Days to Germination

3–10 days

In-row plant spacing

18-24"

Row Spacing

Plant profile

Maturity

Spring, Fall

Life Cycle

Annual

Plant Height

30 inches

Growth Habits

Upright, Spreading

Seed & variety

Seeds Per Ounce

8,900

Color

Green

Seed Type

Open Pollinated

Growing Season

Cool-Season Crop

Before Planting

Reserve a full-sun site for Broccoli with fertile, well-drained soil where brassica crops have not recently grown. Incorporate compost and use a soil test to adjust pH and nutrients, supplying lime before planting only when needed. Prepare a firm, weed-free bed and harden transplants gradually before setting them outdoors.

Planting

Start broccoli indoors 4–6 weeks before transplanting, sowing seed about 1/4–1/2 inch deep. Maintain 70–75°F until emergence, then grow seedlings near 60–65°F under strong light. Harden for one week and transplant 12–18 inches apart while weather is cool. For fall crops, start seed in early to midsummer.

Watering

Provide about 1–1½ inches of water weekly and keep moisture steady while broccoli develops. Water deeply at soil level, especially during heading or enlargement, and avoid prolonged saturation.

Fertilizer

Side-dress broccoli with a nitrogen-containing fertilizer after establishment and during rapid growth if needed. Follow soil-test recommendations and avoid concentrated fertilizer near stems.

Harvesting

Cut the central broccoli head when buds are tight, firm, and fully developed but before yellow flowers open. Leave the plant and side shoots intact; smaller shoots can be harvested repeatedly as they mature.

Tips

Use insect netting or row cover immediately after planting broccoli, securing every edge. Rotate brassicas to a new bed each season, and remove crop residue promptly after harvest.

AVG. Seeding Rate

1,000 seeds/333' at 3 seeds/ft., 49,800 seeds (avg. 8.3 oz.)/acre spaced 7" apart in rows 18" apart.

Pests & Diseases

Black rot produces yellow V-shaped lesions advancing inward from broccoli leaf margins; clubroot causes swollen roots and daytime wilting. Start with clean seed or transplants, rotate brassicas, and keep contaminated soil off tools. Where clubroot exists, improve drainage and raise soil pH toward 6.8 according to a soil test.

Inspect broccoli leaves and developing heads for imported cabbageworms, loopers, flea beetles, aphids, and root maggots. Use insect netting before pest entry, handpick caterpillars, and rotate the next brassica planting.