Count on roughly 70 to 85 days from transplanting to first harvest, then keep the fruit somewhere that holds 45 to 50 °F instead of the refrigerator. Peppers pit and soften when chilled below about 45 °F, and a home fridge runs colder than that. The season here is short, so the dates below work backward from your own transplant day rather than a fixed week. This page is one piece of the wider guide, Growing Peppers in Alaska.
The short answer
At the reference station, Anchorage, the mean number of days a year reaching 90 °F or more is 0.0 (NOAA NCEI Climate Normals). That figure measures summer heat load, meaning the stress that drives water demand and wilts cool-weather plants. It is not an average summer temperature. Utah State University Extension says pepper fruit set fails at both ends: days above 90 °F, or nights below 55 °F. Outdoors at that station, the hot end almost never comes into play.
Both ends of the temperature range
A greenhouse or high tunnel is another matter. Air under glass or plastic can run well above the station’s reading on a sunny afternoon, so vent it. The 0.0 also belongs to Anchorage, one of the mildest inhabited corners of the state. If you garden elsewhere, check your local record rather than borrowing this one.
The cool end is the one this site cannot score for you. Nights under 55 °F also stop fruit set, and this site does not carry summer night minima. Watch your own. A min-max thermometer set at plant height will tell you more than any regional guess, because latitude and the coldest month of winter say nothing reliable about a July night. Log the lows through the weeks when blossoms open. If flowers open and fall, Why Peppers Fail to Set Fruit in Alaska walks through the diagnosis.
The picking window and the fridge
Two clocks run at once. Clemson Cooperative Extension puts harvest at “about 70 to 85 days after transplanting.” The 35 to 45 days for a fruit to ripen run from flowering, not from sowing or transplanting. At Anchorage, about 143 frost-free days follow the last spring frost, so the outdoor part of a pepper’s life takes up roughly half of that. Check your seed packet for the days to maturity of your variety.
Then comes the mistake nearly everyone makes. Clemson’s storage conditions are “temperatures of 45 to 50 °F and 80- to 90-percent relative humidity for two to three weeks.” A domestic refrigerator is colder than that. Below about 45 °F, peppers suffer chilling injury, which shows up as pitted, soft skin. Treat “two to three weeks” as a ceiling under ideal conditions, not a promise. For a spot in that range, put a thermometer where you plan to store them and check it before trusting it. The full factsheet is at Clemson’s pepper page.
When to start seed here
Counting back from transplant
The arithmetic takes four steps, and you can redo it for any county.
- Find your transplant date. It is the later of two dates: the last spring frost where you live, and the day your soil reaches 60 °F. For the Anchorage reference station, NOAA NCEI’s 32 °F freeze probabilities put the last spring frost between May 3 and May 12 (the 30 to 70 percent band, station USW00026451). Soil warming is a separate test, so push a soil thermometer in and read it.
- Subtract 8 to 10 weeks. Utah State University Extension says transplants need that long indoors. In days, that is 56 to 70.
- Work one example through. Suppose your soil reaches 60 °F on June 1 (an illustration, not a recommendation). Ten weeks back is March 23, and eight weeks back is April 6. Your sowing window runs from March 23 to April 6.
- Repeat with your own date. Replace June 1 with the day your soil hit 60 °F last year, or with the frost date your county extension office gives, and count back the same way.
What moves the date
Frost dates are probabilities, not promises. The May 3 to May 12 band is the middle of the range, and a freeze after it is still possible, which is why the soil reading and a look at the forecast outrank the calendar.
Sowing too early costs more than it seems. Seedlings that outgrow their pots indoors while you wait for warm soil are stressed before they ever reach the bed. If your transplant date slips, slide the sowing date with it instead of sowing on schedule and holding the plants.
Waiting also eats into the outdoor window. If harvest comes 70 to 85 days after transplanting, every week lost to cold soil is a week taken from the roughly 143 frost-free days at the reference station. Long summer daylight partly compensates for a short season, but it does not stretch the calendar. Farther into the Interior and the north, the frost-free stretch is far shorter than Anchorage’s, so the same arithmetic leaves much less slack there.
What goes wrong here
- Blossom drop in a hot spell or on a cool night. Flowers open and fall without making fruit when days pass 90 °F or nights dip below 55 °F. Outdoors at the Anchorage station the hot side is rare (0.0 days a year), but a closed greenhouse can get there. Remedy: vent early in the morning, add shade cloth if the structure bakes, and keep a min-max thermometer in the bed to catch the cool nights. Cover plants on nights that threaten to dip below 55 °F. Fruit usually sets again once the weather returns to range.
- Sunscald. Pale, papery, sunken patches show up on the side of the fruit facing the sun. It happens where fruit is suddenly exposed, such as after heavy leaf loss, after transplanting without hardening off, or against south-facing glass. Remedy: keep the leaf canopy intact, harden seedlings off before they go out, and shade fruit under glass at midday. Pick scalded fruit early, since the damaged patch invites rot.
- Blossom-end rot. A dark, leathery, sunken spot forms at the bottom of the fruit. It is tied to calcium failing to reach the fruit, and uneven watering is the usual trigger. Remedy: water evenly instead of in swings, mulch the bed, and get a soil test before adding any calcium product. Remove affected fruit so the plant puts energy into the next ones.
Telling climate damage from pests
All three problems above are marks on fruit that is otherwise intact. Holes, chewed leaves, or missing seedlings point somewhere else, and What Eats Pepper in Alaska, and When covers what to look for and in which weeks.
Common questions
How long after flowering is a pepper ready to pick?
The 35 to 45 days for fruit to ripen run from flowering, not from sowing or transplanting. A plant sown in March and transplanted in early summer may not flower for weeks after it goes in the ground. Mark the date of the first open blossoms and count from there, then use the seed packet’s days to maturity as a cross-check.
Is Alaska too cool for peppers to set fruit?
The hot end barely applies outdoors at the Anchorage reference station, which averages 0.0 days a year at or above 90 °F. The cool end depends on your own nights, because fruit set fails below 55 °F, and this site does not carry summer night minima. Record your lows during bloom and you will know for your own bed.
Can I put peppers in the refrigerator at all?
Clemson’s optimal storage is 45 to 50 °F with 80 to 90 percent relative humidity, which is warmer than a refrigerator. Below about 45 °F peppers pit and soften from chilling injury. The source gives no safe time for fridge storage, so this page will not invent one. A cool spot you have checked with a thermometer is the safer bet for whole fruit.
What date do I sow seed if my county differs from Anchorage?
Take your county’s last spring frost date and the day your soil reaches 60 °F, use the later one, and subtract 8 to 10 weeks. The Anchorage band of May 3 to May 12 is for that station only. Elsewhere in the state the frost-free season can be far shorter, which pushes the whole schedule later and tightens the outdoor window.