Practical planning tools for short growing seasons.
Climate-based broccoli planting guide for Jackson, Wyoming
When to Plant Broccoli in Jackson
In Jackson, broccoli is usually a strong local fit. Most gardeners have some room to work with this crop rather than feeling close to the edge.
Typical Planting Window
Strong fit in this climate
Use the planting dates below for broccoli in Jackson.
Start indoors
May 2
Typical planting windowJune 6 – June 20
MethodTransplant
Typical days to maturity60–75
Broccoli is usually started indoors around May 2 and planted outdoors during the normal local window of June 6 to June 20.
Most varieties need about 60–75 days to reach maturity once they are in the garden.
Broccoli is usually a strong local fit in Jackson. Most gardeners have some room to work with it here rather than feeling pressed against the calendar.
What stronger local margin really changes is that gardeners can wait for a better-finished crop instead of harvesting defensively.
Best local strategy:
Use the normal transplant window and prioritize healthy early growth, spacing, and even moisture.
Can Broccoli Mature in Jackson?
Growing degree days measure how much useful warmth typically accumulates during the season. For broccoli, this helps estimate whether local heat accumulation is usually enough for the crop to reach maturity on time.
Available GDD (base 40)1527
Typical crop GDD target900
Heat margin+627
From the usual planting window, Jackson typically provides about 1527 growing degree days for broccoli. With a typical crop target of 900, that leaves a heat margin of +627. That heat margin usually gives the crop a dependable buffer, so gardeners have some flexibility in planting date and variety choice without pushing the crop close to the edge.
When Is It Too Late to Plant?
If planting later than usual, this table shows how much growing degree day heat is still available from each point in the season. It is most useful for judging how much flexibility you still have before the crop starts losing margin.
Checkpoint
Remaining GDD
Heat margin
Fit vs typical target
Apr 15
2345
+1445
Comfortable
May 1
2333
+1433
Comfortable
May 15
2262
+1362
Comfortable
Jun 1
2098
+1198
Comfortable
Jun 15
1915
+1015
Comfortable
Jul 1
1652
+752
Comfortable
How Different Broccoli Varieties Affect Results
In Jackson, most broccoli varieties are usually realistic choices. Gardeners can often choose across the maturity range without giving up much day-to-day reliability.
Varieties that often fit well here include:
De Cicco
— an early broccoli often chosen where gardeners want flexibility and quicker harvest
Packman
— a dependable standard with good short-season practicality
Green Magic
— a strong early hybrid that often handles the main spring window well
Belstar
— productive and reliable where the season gives a reasonable cool-weather runway
Marathon
— more exposed if spring is delayed or summer heat arrives early
Best Broccoli Varieties for Jackson
Broccoli variety choice in Jackson is mostly about head reliability, side-shoot production, stress tolerance, and how cleanly the crop fits the cool part of the season.
June 20
local season starts
August 31
frost pressure returns
Less heat used1527 GDD available
Hover or tap the dots to see which recommended varieties use that much local heat.
For Jackson, start with Packman and Green Magic for broccoli when you want dependable early broccoli heads or strong early hybrid broccoli.
Choose De Cicco when you want flexible early broccoli and side shoots.
Look at Marathon and Belstar when you specifically want later broccoli plantings or reliable main-season broccoli.
Compare each variety’s heat need and maturity timing against the local frost-free window before choosing what to grow.
Recommended starting point
PackmanEarly
850 GDD needed1527 available before frost
June 20August 31
Comfortable fit
Why this fit?
Local season fit:
Packman leaves about 677 GDD cushion against the normal Jackson crop heat estimate.
Best for: dependable early heads.
A practical early broccoli with good short-season usefulness.
Tradeoff: Practical more than specialty.
Green MagicEarly
850 GDD needed1527 available before frost
June 20August 31
Comfortable fit
Why this fit?
Local season fit:
Green Magic leaves about 677 GDD cushion against the normal Jackson crop heat estimate.
Best for: strong early hybrids.
A strong early hybrid that often handles the main spring broccoli window well.
Tradeoff: Still needs cool growing conditions to finish well.
Fastest / most cushion
De CiccoVery early
750 GDD needed1527 available before frost
June 20August 31
Comfortable fit
Why this fit?
Local season fit:
De Cicco leaves about 777 GDD cushion against the normal Jackson crop heat estimate.
Best for: flexible early broccoli.
An early broccoli that is useful when gardeners want flexibility, side shoots, and a quicker harvest path.
Tradeoff: Heads may be less uniform than hybrid types.
Also realistic
MarathonLate
1050 GDD needed1527 available before frost
June 20August 31
Comfortable fit
Why this fit?
Local season fit:
Marathon leaves about 477 GDD cushion against the normal Jackson crop heat estimate.
Best for: later broccoli plantings.
A slower broccoli that is more exposed if spring is delayed or summer heat arrives early.
Tradeoff: More exposed if spring is delayed or summer heat arrives early.
BelstarMid-season
950 GDD needed1527 available before frost
June 20August 31
Comfortable fit
Why this fit?
Local season fit:
Belstar leaves about 577 GDD cushion against the normal Jackson crop heat estimate.
Best for: reliable main-season broccoli.
A productive broccoli that works well where the season gives a reasonable cool-weather runway.
Tradeoff: Needs more cool-season runway than early broccoli.
GDD comparisons are a planning shortcut, not a guarantee. Soil, watering, sowing depth, pests, transplant quality, and harvest goals still affect the final result.
Variety class
Typical days to maturity
Typical GDD need
Local fit
Very early
55–60
750
Good fit
Early
60–68
850
Good fit
Mid-season
68–78
950
Good fit
Late
78–90
1050
Good fit
Main risk: The usual setback here is giving away seasonal margin through late planting, slow early growth, or slower variety choice than the crop really needs.
How Frost Affects Planting Dates for Broccoli in Jackson
Jackson usually has about 72 frost-free days, with a typical last spring frost around June 20 and a typical first fall frost around August 31.
Typical last spring frostJune 20
Typical first fall frostAugust 31
Typical frost-free days72
Minimum safe temperature28°F /
-2
°C
Broccoli is generally
lightly frost tolerant
and temperatures below about 28°F (
-2
°C) can slow growth or damage plants.
Broccoli is usually tolerant enough of cool conditions that light frost is not the main concern. The more useful question is how early planting affects establishment and overall crop quality.
Problems here usually come from giving up part of the season through late planting, weak early growth, or slower variety choice than the crop really needs.
In Jackson, broccoli already has plenty of seasonal room when planted around June 13. In practical terms, the best spots are usually south-facing walls, sheltered gardens, raised beds, and sunnier urban lots. Cooler spots like low spots, exposed sites, and shadier yards are more likely to stay cooler and be less forgiving. For broccoli, warmer local sites usually help the crop get established earlier and grow a little more steadily.
Set up broccoli for steady growth and pest protection
The better results usually come from steady growth, pest protection, and avoiding early setbacks.
Transplant support
Strong young plants help avoid slow starts and uneven sizing.