Practical planning tools for short growing seasons.
Climate-based pepper planting guide for Casper, Wyoming
When to Plant Peppers in Casper
Peppers are usually a good match for the season in Casper. Gardeners generally have enough margin to think about preference and quality, not just speed.
Typical Planting Window
Strong fit in this climate
Use the planting dates below for peppers in Casper.
Start indoors
April 7
Typical planting windowJune 11 – June 21
MethodTransplant
Typical days to maturity70–85
Peppers are usually started indoors around April 7 and planted outdoors during the normal local window of June 11 to June 21.
Most varieties need about 70–85 days to reach maturity once they are in the garden.
Peppers are usually a strong local fit in Casper. Most gardeners have some room to work with it here rather than feeling pressed against the calendar.
Even as a stronger fit here, this crop still improves when warmth is used to turn workable ripening into a better finish.
Best local strategy:
Treat the season as supportive, then focus on consistency and crop quality more than simple maturity insurance.
Can Peppers Mature in Casper?
Growing degree days measure how much useful warmth the season provides. For warm-season crops like peppers, GDD helps show whether local heat accumulation is usually strong enough for the crop to grow steadily and finish before fall.
Available GDD (base 50)1815
Typical crop GDD target1300
Heat margin+515
From the usual planting window, Casper typically provides about 1815 growing degree days for peppers. With a typical crop target of 1300, that leaves a heat margin of +515. 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
1970
+670
Comfortable
May 15
1968
+668
Comfortable
Jun 1
1888
+588
Comfortable
Jun 15
1749
+449
Comfortable
Jul 1
1513
+213
Comfortable
How Different Pepper Varieties Affect Results
The season in Casper usually supports most pepper varieties comfortably, which means the more useful decision is what kind of crop you want rather than simply how fast it finishes.
Varieties that often fit well here include:
King of the North
— a classic short-season bell pepper chosen for earlier maturity in cooler climates
Ace
— often grown where gardeners want dependable bell peppers without pushing late-season risk
Gypsy
— an earlier hybrid sweet pepper that matures more quickly than many full-size bells
Lipstick
— sometimes treated as relatively early, though fuller ripening still improves with more heat
California Wonder
— a familiar standard bell pepper, but usually more comfortable where the season has decent heat
Carmen
— a tapered sweet pepper that can perform well when the local season is supportive
Best Pepper Varieties for Casper
Early pepper varieties are usually the strongest all-around match in Casper. The local season can support peppers only when plants get a warm start, steady growth, and enough heat to ripen before conditions fade.
May 26
local season starts
September 22
frost pressure returns
Less heat used1815 GDD available
Hover or tap the dots to see which recommended varieties use that much local heat.
For Casper, start with Gypsy and Lipstick for peppers when you want early sweet peppers or early red sweet peppers.
Choose Ace and King of the North when you want short-season bell peppers or cool-climate bell peppers.
Look at Chocolate Beauty, Marconi Red, and California Wonder when you specifically want specialty bell color, large red sweet peppers, or standard bell peppers.
Compare each variety’s heat need and maturity timing against the local frost-free window before choosing what to grow.
Recommended starting point
GypsyEarly
1100 GDD needed1815 available before frost
May 26September 22
Comfortable fit
Why this fit?
Local season fit:
Gypsy leaves about 715 GDD cushion against the normal Casper crop heat estimate.
Best for: early sweet peppers.
An earlier sweet pepper that can be a practical choice when full-size bells feel too slow for the local season.
Tradeoff: Not a classic blocky bell pepper.
LipstickEarly
1100 GDD needed1815 available before frost
May 26September 22
Comfortable fit
Why this fit?
Local season fit:
Lipstick leaves about 715 GDD cushion against the normal Casper crop heat estimate.
Best for: early red sweet peppers.
A sweet pepper that can ripen earlier than many standard bells, though full color still benefits from steady warmth.
Tradeoff: Full red color still takes enough warm weather.
Fastest / most cushion
AceVery early
950 GDD needed1815 available before frost
May 26September 22
Comfortable fit
Why this fit?
Local season fit:
Ace leaves about 865 GDD cushion against the normal Casper crop heat estimate.
Best for: short-season bell peppers.
A very early bell pepper that gives short-season gardeners one of the more realistic paths to ripe fruit.
Tradeoff: Ripe color still depends on warmth and timing.
King of the NorthVery early
950 GDD needed1815 available before frost
May 26September 22
Comfortable fit
Why this fit?
Local season fit:
King of the North leaves about 865 GDD cushion against the normal Casper crop heat estimate.
Best for: cool-climate bell peppers.
A classic short-season bell pepper often chosen where summers are cooler or the frost-free window is tight.
Tradeoff: Still a pepper, so cold starts can erase the advantage.
Also realistic
Chocolate BeautyLate
1500 GDD needed1815 available before frost
May 26September 22
Comfortable fit
Why this fit?
Local season fit:
Chocolate Beauty leaves about 315 GDD cushion against the normal Casper crop heat estimate.
Best for: specialty bell color.
A slower coloring bell pepper that is better chosen for novelty and flavor than for short-season safety.
Tradeoff: Chosen for novelty more than short-season safety.
Marconi RedLate
1500 GDD needed1815 available before frost
May 26September 22
Comfortable fit
Why this fit?
Local season fit:
Marconi Red leaves about 315 GDD cushion against the normal Casper crop heat estimate.
Best for: large red sweet peppers.
A larger sweet pepper that usually needs a long, warm season to size and color well.
Tradeoff: Needs more time to size and color than faster peppers.
California WonderMid-season
1300 GDD needed1815 available before frost
May 26September 22
Comfortable fit
Why this fit?
Local season fit:
California Wonder leaves about 515 GDD cushion against the normal Casper crop heat estimate.
Best for: standard bell peppers.
A familiar bell pepper that is best treated as a main-season choice rather than the safest short-season option.
Tradeoff: Slower and less forgiving than the earliest pepper choices.
CarmenMid-season
1300 GDD needed1815 available before frost
May 26September 22
Comfortable fit
Why this fit?
Local season fit:
Carmen leaves about 515 GDD cushion against the normal Casper crop heat estimate.
Best for: tapered sweet peppers.
A productive tapered sweet pepper that can do well when the season is warm enough to support steady ripening.
Tradeoff: Still needs steady warmth for good ripening.
Corno di ToroMid-season
1300 GDD needed1815 available before frost
May 26September 22
Comfortable fit
Why this fit?
Local season fit:
Corno di Toro leaves about 515 GDD cushion against the normal Casper crop heat estimate.
Best for: large sweet frying peppers.
A flavorful long pepper that is more rewarding where plants get a strong run of warmth.
Tradeoff: Better with a longer warm season.
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
60–70
950
Good fit
Early
65–75
1100
Good fit
Mid-season
75–85
1300
Good fit
Late
85–100
1500
Good fit
Main risk: When this crop underperforms in Casper, the culprit is usually timing or variety choice rather than the climate itself.
How Frost Affects Planting Dates for Peppers in Casper
Casper usually has about 119 frost-free days, with a typical last spring frost around May 26 and a typical first fall frost around September 22.
Typical last spring frostMay 26
Typical first fall frostSeptember 22
Typical frost-free days119
Minimum safe temperature32°F /
0
°C
Peppers are generally
frost-tender
and temperatures below about 32°F (
0
°C) can slow growth or damage plants.
Peppers are much more exposed to frost risk, so the frost dates matter as real planting boundaries rather than rough planning markers.
When this crop underperforms in Casper, the culprit is usually timing or variety choice rather than the climate itself.
In Casper, the local season usually gives peppers plenty of breathing room when planting happens around June 5. For a better local margin, gardeners usually do best in south-facing walls, sheltered gardens, raised beds, and sunnier urban lots. Cooler spots like low spots, exposed sites, and shadier yards often make timing tighter. For peppers, the main gain is usually better finishing and earlier color rather than a simple question of whether the crop works at all.
Set up peppers for steady watering and better fruit quality
The best purchases are the supplies that improve support, watering, and fruit quality rather than simply forcing the crop to mature.
Support and training
When the crop fits, supports help turn a good seasonal fit into a cleaner harvest.