Peppers in zone 6 need warm nights more than an early start

Pepper plants in zone 6 go outside from early May to early June. Set them out too soon and they won’t die, they’ll just stop, and a pepper that has sat through a few cold nights can take weeks to start growing again.

Start the seeds indoors early, from early February to early March. Peppers are slow, and they need 10 weeks or more under lights to make a good transplant.

Timing in zone 6

Zone 6’s last frost is usually around April 21, and the first fall frost comes around mid-October. Peppers need the warm part of that season.

Job	When
Sow indoors	Early February to early March
Transplant outside	Early May to early June
First peppers	Mid-July onwards
Last picking	Up to the first frost, around mid-October

The signal to plant isn’t the date, it’s the nights. Wait until the overnight lows are reliably above 50 °F and the soil feels warm to your hand. In a cool spring that can be late May.

Zones describe winter lows rather than frost dates, so use these as a starting point. Hillside and valley gardens can run a couple of weeks later. City gardens often run earlier.

Starting seeds

1. Sow a quarter inch deep in seed-starting mix, two seeds to a cell.
2. Keep the mix warm, ideally around 80 °F, with a heat mat. Pepper seed sulks in a cool room.
3. Once the seedlings are up, give them bright light for 14 to 16 hours a day, with an LED light a few inches above the leaves. Turn the heat mat off.
4. Pot them on into 4-inch pots when they have two or three true leaves.
5. Harden them off for a week before transplanting.

Planting out

• Choose your sunniest, most sheltered spot. Peppers want all the heat they can get.
• Space plants 18 inches apart in rows 2 feet apart.
• Black plastic or landscape fabric laid a week before planting warms the soil by several degrees. Cut holes and plant through it.
• Have row cover ready for cold nights in the first few weeks.
• A short stake helps heavily cropping plants, which can snap in a storm.

Basil, marigolds, carrots and onions make good neighbours.

Through the summer

Peppers start cropping 60 to 90 days after transplanting, usually from mid-July. Water steadily, deeply, once or twice a week, and mulch once the soil is warm. Uneven watering leads to blossom end rot, the same dark sunken patch tomatoes get.

Pick the first few fruit green to keep the plant producing. Later in the season, leave some to turn red, yellow or orange. Colored peppers are sweeter, but each one takes several more weeks on the plant.

When frost is forecast in October, pick everything, including small green fruit.

Common problems

Flowers dropping. Peppers drop blossoms when nights are cold in spring or when days are very hot in midsummer. They start setting again as the weather evens out.

Slow, yellowish plants in June. Usually cold soil from planting too early. They’ll recover once the weather warms. Feed lightly.

Sunscald. Pale, papery patches on fruit exposed to strong sun. Plants with plenty of leaves shade their own fruit, so avoid pruning.

Aphids. Clusters under the leaves. Hose them off, and check the undersides of leaves every week or so.

Pick zone 6 on the pepper page for every window on one chart. If you’re setting up lights and trays for the first time, the zone 5 seed starting guide covers the kit, and the method is the same in zone 6.