How to Grow Marrowstem Kale USA

By the SoilCommander Editorial Team, under the guidance of Nitin Sharma, Co-Founder · · How we check our facts

On this page
  1. Marrowstem Kale (Brassica oleracea var. medullosa)
  2. Soil & Growing Conditions
  3. Growth Stages
  4. Quick Facts
  5. At a Glance
  6. Harvest & Storage
  7. Diseases
  8. Pests
  9. Marrowstem Kale, Grown for the Stem
  10. Plan your Marrowstem Kale planting
  11. Growing Marrowstem Kale in another region
  12. Sources
  13. Frequently Asked Questions

Marrowstem kale (Brassica oleracea var. medullosa) — biennial or perennial.

Unlike an annual crop, the work here is front-loaded into establishment: get the planting and the site right and the same plants crop for several seasons.

The short answer

Site
soil pH 4.2–8.3
Biggest risk
Club root

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

Marrowstem Kale (Brassica oleracea var. medullosa)

A stand of mature marrowstem kale showing the tall, thick, pale stems the variety is grown for — “MarkstammkohlBestand” by Goldlocki is licensed under CC BY-SA 3.0.

Also known as: marrow-stem kale · 2 sources cited · Single source

Soil & Growing Conditions

A marrowstem kale plant showing the thickening pale stem and blue-green leaves — “Markstammkohl im Sommer” by Submeir is licensed under CC BY-SA 4.0.
“Markstammkohl im Sommer” by Submeir is licensed under CC BY-SA 4.0.

Water: moist, well-drained (PFAF)

Soil pH range

4.2 8.3

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

Growth Stages

A stand of mature marrowstem kale showing the tall, thick, pale stems the variety is grown for — “MarkstammkohlBestand” by Goldlocki is licensed under CC BY-SA 3.0.
“MarkstammkohlBestand” by Goldlocki is licensed under CC BY-SA 3.0.
Stage BBCH Notes
Sowing 0 Direct seed outdoors in April/May into a seedbed (PFAF).
Transplanting 1 Transplant summer seedlings to their permanent position, avoiding overcrowding, which causes legginess; deeper planting encourages stronger root formation (PFAF).
Stem and leaf growth 3 Grows to about 0.9m (3ft) tall, developing its characteristic large, succulent, nutritious main stalk (PFAF).
Winter harvest 8 Extremely cold-tolerant, to about 5°F (-15°C); prized for winter harvesting in cold climates once other crops have finished (PFAF).

Quick Facts

A marrowstem kale plant showing the thickening pale stem and blue-green leaves — “Markstammkohl im Sommer” by Submeir is licensed under CC BY-SA 4.0.
“Markstammkohl im Sommer” by Submeir is licensed under CC BY-SA 4.0.
Factor Value
Soil pH 4.2 - 8.3
Soil texture light, medium or heavy soil, prefers heavy/clay (PFAF)
Drainage well-drained
Lifecycle biennial or perennial
Edible parts leaves, young flowering shoots, stem

At a Glance

A stand of mature marrowstem kale showing the tall, thick, pale stems the variety is grown for — “MarkstammkohlBestand” by Goldlocki is licensed under CC BY-SA 3.0.
“MarkstammkohlBestand” by Goldlocki is licensed under CC BY-SA 3.0.
Brassica oleracea var.… Marrowstem Kale Club root Downy mildew (general) Cabbage root fly (US: c… Flea beetles DISEASES PESTS

Harvest & Storage

A marrowstem kale plant showing the thickening pale stem and blue-green leaves — “Markstammkohl im Sommer” by Submeir is licensed under CC BY-SA 4.0.
“Markstammkohl im Sommer” by Submeir is licensed under CC BY-SA 4.0.

When to pick: Prized for winter harvesting in cold climates; extremely cold-tolerant to about 5°F (-15°C). Foliage toughens with age, so leaves are best used young; young flowering shoots taste similar to sprouting broccoli when cooked (PFAF).

Diseases

A stand of mature marrowstem kale showing the tall, thick, pale stems the variety is grown for — “MarkstammkohlBestand” by Goldlocki is licensed under CC BY-SA 3.0.
“MarkstammkohlBestand” by Goldlocki is licensed under CC BY-SA 3.0.
moderate

Plasmodiophora brassicae

Likely rather than confirmed: no source names this crop directly, but it shares a species (Brassica oleracea) with Kale, which lists this disease.

Downy mildew (general)
moderate

Likely rather than confirmed: no source names this crop directly, but it shares a species (Brassica oleracea) with Kale, which lists this disease.

Pests

A marrowstem kale plant showing the thickening pale stem and blue-green leaves — “Markstammkohl im Sommer” by Submeir is licensed under CC BY-SA 4.0.
“Markstammkohl im Sommer” by Submeir is licensed under CC BY-SA 4.0.
Cabbage root fly (US: cabbage maggot)
moderate

Delia radicum

Likely rather than confirmed: no source names this crop directly, but it shares a species (Brassica oleracea) with Kale, which lists this pest.

Flea beetles
moderate

Chrysomelidae: Alticini (various spp.)

Likely rather than confirmed: no source names this crop directly, but it shares a species (Brassica oleracea) with Kale, which lists this pest.

Plan your Marrowstem Kale planting

When to sow and plant Marrowstem Kale depends on your own frost dates. Check the USA vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.

Growing Marrowstem Kale in another region

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

Sources

The full list of 2 sources behind this guide (PFAF (Plants For A Future), Plants For A Future (PFAF)) is in the references of our UK guide to marrowstem kale; they describe the plant itself, which is the same wherever it grows.

Frequently Asked Questions

What soil pH does marrowstem kale need?

A pH of about 4.2–8.3. 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 marrowstem kale?

Our data links 2 diseases and 2 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.

Get the USA Garden Planner →

Instant PDF download · Written for US growing conditions

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

Every growing guide is checked against RHS, USDA Cooperative Extension, and other named horticultural authorities before publishing. How we check our facts.

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.

Vegetable Growing Guides USA

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Last verified 2026-08-29

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