Pepper Growing Zones and the 50°F Nights That Matter More

On this page

1. 1What zone do peppers grow in?
2. 2Which temperatures matter for peppers?
3. 3Is it time to plant your peppers out?
4. 4How do you measure soil temperature before you plant out?
5. 5How long is your pepper season?
6. 6How do you stretch a short or cool season?
7. 7What should you do on a frost advisory night?
8. 8How many degrees does each kind of cover buy you?
9. 9When do you plant peppers in hot climates?
10. 10How do you protect peppers in a heat wave?
11. 11Does your microclimate change the dates?
12. 12What goes wrong when the weather does not cooperate?
13. 13Find your planting dates

What zone do peppers grow in?

All of them, as long as you get a warm stretch of summer. Peppers cannot take frost¹, so in most of the country you grow them as a summer crop: planted after the spring frost and picked before the fall one. Your zone number says how cold your winter gets, which matters little to a plant that never sees your winter.

You can look yours up by typing your ZIP code into the USDA map². Just know what the number leaves out, because the things it skips are the things your peppers care about.

For peppers, read your zone as a rough hint about season length and plan from your frost dates and summer temperatures instead.

Which temperatures matter for peppers?

Five lines on the thermometer decide most of your pepper season: the soil temperature at planting, the coldest night your plant can take outside, the comfortable middle, the hot nights that stop pods and the heat that ruins pollination.

The temperature chart at the top of the page puts them on one scale. Read the soil and night rows as your planting signal, and the hot end of the day row as the reason a plant in full flower can set nothing in a heat wave. At the cold end, UF/IFAS says pepper plants take cold injury once the air drops 2°F below freezing⁴.

The fruit-set limits deserve a closer look, because the sources draw them a few degrees apart. Here is each one as published.

When pepper flowers stop setting fruit, by source

Too cold	Too hot
Nights below 60°F	Nights above 75°F, or days above 95°F
Below 60°F	Above 90°F
Nights below 55°F	Days above 90°F
No figure given	Days above 100°F cut pollination, fruit set and yield

Put together, your pepper sets fruit most reliably with nights between about 60 and 75°F and days below 90°F⁵⁶. Outside that band the plant keeps growing leaves and waits. UMN Extension adds that smaller-fruited peppers handle both cool and hot weather better than big bells⁸, which helps you at both ends of the scale.

Is it time to plant your peppers out?

Only when the soil and the nights both agree. One warm afternoon proves nothing; the plant reacts to cold soil and cold nights, and both lag behind the air in spring.

Has your last spring frost passed?Penn State plants out 2 to 3 weeks after it

• yes
  Does the soil read 60°F or more?Penn State's floor for transplanting
  • yes
    Do nights stay above 50°F?UMN keeps plants inside until they do
    • yes
      Plant outAt 65°F soil the plants start growing right away
    • no
      Wait a week and check againBelow 65°F soil, transplants just sit there
  • no
    Wait a week and check againBelow 65°F soil, transplants just sit there
• no
  Wait a week and check againBelow 65°F soil, transplants just sit there

^{3 sources}Sources for this line8. University of Minnesota Extension9. PlantVillage, Penn State University10. University of Maryland Extension

Penn State's floor is 60°F soil⁹; Maryland says plants set into soil below 65°F "just sit there"¹⁰; UMN keeps them inside until nights stay above 50°F⁸. If you can wait for 65°F, your plants lose no time sulking.

How do you measure soil temperature before you plant out?

Push a soil thermometer into the bed on three mornings in a row and plant once it reads 60°F or more. UW–Madison Extension takes the reading between 10 a.m. and noon, 4 to 6 inches deep for transplants and 2 inches for seed¹¹.

1. 1

   Buy a thermometer for soil only

   UW–Madison suggests a soil thermometer that you use for nothing else.¹¹

2. 2

   Read it at the same time three days running

   Take each reading between 10 a.m. and noon, so one warm afternoon cannot fool you.¹¹

3. 3

   Push the probe to root depth

   Go 4 to 6 inches down for a transplant, or 2 inches if you sow seed in the bed.¹¹

4. 4

   Compare it with the number you trust

   The services draw the line at different degrees, so pick one from the table and stick to it.^{4 sources}Sources for this line9. PlantVillage, Penn State University10. University of Maryland Extension11. UW–Madison Extension, Wisconsin Horticulture (Lisa Johnson)12. South Dakota State University Extension

The numbers differ because each service answers a slightly different question. Here is what each one prints for peppers.

How warm the soil must be, by service

Service	Soil temperature	What it means
Penn State PlantVillage	60°F	The floor for transplanting
Maryland Extension	65°F	Below this, transplants just sit there
South Dakota State Extension	65°F	The minimum soil temperature for peppers, which people usually grow from transplants
UW–Madison Extension	65°F minimum, 85°F best, 60–95°F range	For pepper seed sown in the bed, read at 2 inches

Maryland says plants set into soil below 65°F just sit there¹⁰, so a few extra days of waiting cost you little. Set your own line at 65°F whenever the forecast lets you.

How long is your pepper season?

Count the days between your last spring frost and your first fall frost, then take off the 2 to 3 weeks Penn State waits before planting out⁹. What is left is the time your plants have to ripen, and Maryland gives most sweet and hot types 70 to 85 days from transplant against 90 to 120 for habanero types¹⁰.

Three example gardens, worked from their frost dates

Last spring frost	First fall frost	Plant out (2–3 weeks after)	Days left to the fall frost	Most types (70–85 days)	Habanero types (90–120 days)
June 1	September 15	June 15–22	85–92	Just fits	Too short outdoors
May 15	September 30	May 29 – June 5	117–124	Fits	Tight; start them first
April 20	October 20	May 4–11	162–169	Fits, with weeks to spare	Fits

The short garden in the first row is the one to plan hardest. There you pick fast varieties, start the early-maturing peppers indoors on time, and give a habanero a pot you can carry inside before the first frost¹³.

How do you stretch a short or cool season?

Warm the soil early and keep the plant warm at night. UC IPM says a cool climate can stop plants growing, drop their blossoms and keep peppers from forming or ripening at all, and its only fix is to plant when the weather is warmer¹⁴. You can make that warmer weather arrive sooner in your own bed.

A greenhouse is the bigger step. New Mexico State grows transplants to size in 6 to 8 weeks in a home greenhouse⁶, which shows how much faster peppers move when you keep them warm.

A thermometer, a cover and a roll of plastic do the checking and the warming from that list, so here is what each one is for.

Tools that warm a cold spring bed

A thermometer tells you when; plastic and a cover make the soil and the night warmer.

1. 

   Soil thermometer

   Our pick

   You read it before planting so you do not set transplants into cold soil where they just sit there.

   Where

   4 to 6 inches deep for transplants, 2 inches for seed

   How often

   Three mornings in a row, between 10 a.m. and noon

   Best for

   Checking for 65°F soil, UW–Madison's minimum

   Taylor Soil Thermometer for Seed Germination and Planting | Analog Dial with Min, Max and Optimal Ranges, Stainless Steel 4-Inch Stem, Measures 20 to 180 Degrees F

   $7.98

   View on Amazon: Soil thermometer
2. 

   Floating row cover

   You lay it over the bed on cold spring nights to hold a few degrees of warmth.

   Protection

   Up to 10°F of frost protection, by material and grade

   Where

   Over the bed, held up on wire hoops

   How often

   Open it for air above 80°F

   Valibe Plant Covers Freeze Protection 10 ft x 30 ft Floating Row Cover 0.9oz/yd² Garden Fabric Plant Cover for Winter Frost/Sun Pest Protection (10FT X 30FT)

   $17.99

   View on Amazon: Floating row cover
3. 

   Black plastic mulch

   You lay it before planting to warm the soil early in the season.

   Where

   Over the bed before transplanting

   Best for

   Cool springs

   Farm Plastic Supply - Poly Mulch Black Plastic Sheeting - Poly Mulch, Mulch, Black Plastic Sheeting (1.5 mil - 3' x 1000')

   $119.99

   View on Amazon: Black plastic mulch

4 sources

As an Amazon Associate we earn from qualifying purchases. We choose product types from what their labels and extension sources say; the commission does not change what we recommend. Our affiliate disclosure

What should you do on a frost advisory night?

Cover the plants before sunset and water the soil. The National Weather Service office in Charleston, West Virginia, issues a Frost Advisory when it expects widespread frost during the growing season, usually with lows of 33 to 36°F on a clear, calm night, and it says minor damage to sensitive plants is possible¹⁶. Offices set their own cutoffs, so check your local forecast for the exact numbers.

1. 1

   Read the forecast low

   A Frost Advisory means lows of 33 to 36°F. A Freeze Warning means 29 to 32°F, and the NWS says a freeze will likely kill unprotected sensitive plants.¹⁶

2. 2

   Water the soil in the afternoon

   Wet soil holds heat better than dry soil, so a soak before dark helps the plants through the night.¹⁶

3. 3

   Cover the plants before the sun sets

   A dry sheet or blanket works. Wet fabric cools the plants through evaporation, so keep it dry.¹⁵¹⁶

4. 4

   Take the cover off the next morning

   Remove blankets and sheets in the daytime so the soil can recharge the heat it stores.¹⁵

5. 5

   Move pots indoors

   If you can, carry potted peppers inside; a freeze will likely kill plants left out.¹⁶

Colorado State splits frosts into two kinds. A radiation frost comes on a calm, clear night and usually sits only a few degrees below the damage point, so covering is worth the effort; a cold front can drop temperatures far enough that protection is a long shot¹⁵.

How many degrees does each kind of cover buy you?

A floating row cover gives up to 10°F of protection, and the extras you add to a frame stack on top of that. Colorado State reports the frame numbers from Fort Collins trials on a plastic-covered cold frame, four feet wide and five feet long.

Frost protection by cover type

Cover	Frost protection	The catch
Blankets and sheets	No figure given	Keep them dry and remove them each day
Floating row cover	Up to 10°F, by material and grade	Take it off for pollination on insect-pollinated crops
Plastic cover on a frame	3°F to over 6°F	Vent it on sunny days; open it in a hot summer
Plastic frame plus a space blanket, aluminized side down	Held a frame above freezing when outside air fell to 0°F after a sunny day	Remove the blanket every day
Plastic frame plus a 25-light string of C-7 Christmas lights	6°F to over 18°F	Lights on at dusk, off at dawn
Frame with lights and a space blanket	18°F to over 30°F	The most work and the most protection
Water-filled ring around one plant	Down to the mid-teens	The plant outgrows the ring

For a bed of peppers the row cover is the easy default, and the frame with lights is the move for the one cold night that threatens a whole season. Plastic mulch laid before planting, which the stretch-the-season checklist above covers, warms the soil the same way from underneath.

When do you plant peppers in hot climates?

In the hottest places you plant in late summer, fall or winter, so your plants flower outside the worst heat. UF/IFAS lists a spring and a late-summer window for north Florida and a window from August through February for south Florida¹⁸; the planting-month chart on this page shows every region. UF/IFAS Gardening Solutions adds that you can start seeds again in midsummer for an early fall planting in August and September¹⁹.

California splits by region the same way. UC IPM gives approximate dates and tells you to check with your local Master Gardener program for closer ones¹.

Hot climates suit some peppers well. UF/IFAS says habanero thrives in hot places such as Miami-Dade County and south Florida⁴, so a southern garden that struggles with bells can still do well with your chinense types.

How do you protect peppers in a heat wave?

Shade the plants in the afternoon, keep the soil evenly wet and leave every leaf on. Peppers want at least 6 hours of direct sun, and 8 to 10 is better¹⁰, but a heat wave turns that sun against the pods.

1. 1

   Add late-afternoon shade

   Maryland shades peppers in the late afternoon and says it can improve yields over the season.⁵

2. 2

   Cool the plants with water

   Spray the plants with water during hot, dry spells, when nights stay above 75°F.¹⁰

3. 3

   Shade new transplants at midday

   For a summer planting, UC IPM shades transplants in the middle of the day for their first week.¹

4. 4

   Keep the leaf cover

   Fruit exposed to hot sun after the leaves wilt turns brown and leathery; water and feed for a full canopy.²⁰

Then wait. Flowers that drop in the heat come back once the weather eases, and New Mexico State notes that heat and water stress also change how hot your pods taste⁶.

Does your microclimate change the dates?

Yes, by a few degrees either way. USDA points to warm spots, such as a sheltered bed in front of a south-facing wall or the blacktop of a city, and to cold pockets where air pools in a low spot or between small hills². A pepper bed against your south wall can go out a little earlier than one at the bottom of your slope.

The warm-spot cards on this page show the three places USDA names. Use them twice a year: in spring to choose where your earliest plants go, and in fall to know which bed the first frost will reach first.

What goes wrong when the weather does not cooperate?

Most climate trouble shows up as a plant that grows but will not set or ripen. Match what you see to its likely cause.

Weather problems on peppers and what to do

What you see	Likely cause	What to do
Transplants sit still for weeks710	Soil below 65°F at planting	Wait for warmer soil; warm it with plastic mulch next year
Blossoms drop all at once in midsummer57	Nights above 75°F or days above 90–95°F	Shade in the afternoon, water evenly, wait for cooler nights
Plants stall and pods never ripen814	A cool climate	Plant later into warm soil; grow smaller-fruited types
Brown, leathery patch on the sunny side of a pod20	Sunburn after the leaves wilted	Keep the plant watered and fed for leaf cover
Blackened leaves after a clear, still night14	Frost or a freeze	Pick every pod before the first fall frost; cover or move plants on cold nights

Find your planting dates

Your county extension office knows the local frost dates; USDA sends you to extension services for exactly that kind of detail². Write down your last spring frost and your first fall frost, then count the days between them as in the worked table above.

Once you have those two dates, the guide to when to plant peppers turns them into a sowing date, a planting-out date and a first-harvest window for your garden.