Growing Tips for Successful Pepper Seedlings

Peppers are one of the most varied and profitable vegetables many growers raise. There are dozens of types, in all sorts of colors, shapes and flavors, from sweet bells to pungent habanero.

Peppers also offer versatility: pick them green or let them ripen to full color, which stretches your harvest and makes for eye-catching multicolored displays. Sell them fresh, dried (bagged or as ristras), pickled, or roasted if you have the equipment. Price them individually, or sell snack-size peppers in clamshells or bags. Growing hot or specialty sweet peppers for international cuisines can even open up new markets.

To take advantage of everything peppers offer, you'll need to raise your own transplants. Pepper seedlings aren't difficult, but they are a bit fussy, and since transplant quality can affect yield, it pays to give young plants what they need.

These tips will help your pepper seedlings get off to a strong start.

Peppers set fruit best between 65°F (18°C) and 85°F (29°C).

Timing matters with peppers because their best performance falls within a span of about 30 degrees. Like tomatoes and eggplant, they're warm-season fruiting crops and won't thrive below about 60°F (16°C). At the top end, fruit set drops off sharply above 90°F (32°C), especially in bell peppers, though some hot peppers handle heat better.

Ideally, set peppers out as soon as the weather is reliably warm, so they set fruit while temperatures are between 65°F (18°C) and 85°F (29°C).

Of course, you can't control the weather, and some places and seasons never offer ideal conditions. An early heat wave, for example, can throw off the timing and size of the harvest. Early yields may drop, but plants keep growing leaves and stems until conditions allow fruit set to pick up again.

Seed into 20-row seed flats and provide bottom heat give the best germination.

Sow about 8 weeks before transplanting, ¼" deep in a fine seed-starting mix or vermiculite for good drainage. A 20-row flatworks well: its shallow furrows let you use less mix while fitting more seeds onto a heat mat. The rows also make it easy to start several varieties and keep them apart. (Choosing exactly the varieties you want, in the quantities you want, is one of the perks of raising your own seedlings.)

Bottom heat at 80–90°F (27–32°C) is key to germinating peppers; at that temperature seedlings emerge in about 7–8 days. Cooler soil makes germination slower, uneven and lower.

Moving seedlings into 50-cell trays

After they sprout, pepper seedlings need plenty of full-spectrum light. At seed-starting time in many regions, a window won't provide enough, and some grow lights fall short too. Our grow light buying guide explains light quality and how to pick a fixture that fits your setup.

About two weeks after germination, when true leaves start to appear, gently separate the seedlings and move them into cell trays or pots.

Cell size is a balancing act. You want roots to fill the cell so the root ball stays together at transplanting, but you don't want plants rootbound, especially if bad weather delays planting; oversized, rootbound transplants are badly stressed and yield less. You also need to make good use of greenhouse or indoor space, so there's no point growing transplants bigger than necessary.

Generally, a 50-cell or 72-cell tray works well for pepper seedlings that will grow 8–10 weeks before going out.

Pepper seedlings growing in a greenhouse

After moving seedlings to cell trays, grow them at about 70°F (21°C) during the day and 60°F (16°C) at night. Use a well-draining mix and avoid overwatering; let it dry before watering again. Once or twice a week, water with fertilizer diluted to about 100 ppm.

You can also drench plants with RootShield^®, an OMRI-listed biological containing a beneficial fungus that helps protect roots from soilborne diseases such as Pythium and Fusarium.

Harden seedlings off before transplanting.

By 7–8 weeks old, seedlings should be about 6–8" tall,

ideally with some flower buds but no open flowers.

Harden them off by lowering daytime temperatures to 60–65°F (16–18°C) for a week before transplanting.

Pepper transplants just mulched and covered

Peppers do best in fertile, well-drained soil around pH 6.5. Adequate phosphorus and calcium support good yields.

Once the weather is settled and frost danger has passed, set peppers out in the field, hoophouse or greenhouse.

Plant them slightly deeper than the root ball to encourage extra roots and sturdier plants.

Plastic mulch and row cover add warmth, which helps with earliness and yield. Support the row cover on hoops so it doesn't rub the tender shoot tips.

Peppers have perfect flowers, with male and female parts in each flower, so they can pollinate themselves. Bees and other pollinators aren't essential for fruit set.

See our field pepper tech sheet for detailed recommendations.

Follow these tips for healthy pepper seedlings. With good transplants and kind summer weather, peppers can be a profitable crop for your farm.

For more on growing peppers, see:

• Peppers • Key Growing Information
• Greenhouse Peppers • Key Growing Information
• Growing field peppers (tech sheet, PDF)
• Growing greenhouse bell peppers (tech sheet, PDF)
• Visit our pepper growing resources for everything we have on growing peppers!