Grow file · Marconi Red (Capsicum annuum)
Marconi Red Pepper
Capsicum annuum
A long Italian sweet pepper that chars and peels in one piece. Romesco and any red-pepper paste want this, not a supermarket bell.
| Days to maturity | 80 days from transplant |
|---|---|
| Days to germinate | 7–14 days at 80 °F |
| Germination soil temp | 75–85 °F |
| Start indoors | 8 weeks before last frost |
| Transplant | 1 weeks after last frost |
| Spacing | 18″ between plants |
| Sun | 6–8 hours direct |
| Container size | 5 gal minimum per plant |
| Realistic yield | 3.5 lb per healthy plant, per season |
| Heat | 0 SHU |
Your dates, by zone
Built from each zone's average last frost and this cultivar's 80-day maturity. Zone averages are not your garden — enter your own frost date in the builder to shift every row.
| Zone | Sow indoors | Transplant | First pick |
|---|---|---|---|
| Zone 3 | Mar 20 | May 22 | Aug 10 |
| Zone 4 | Mar 17 | May 19 | Aug 7 |
| Zone 5 | Mar 5 | May 7 | Jul 26 |
| Zone 6 | Feb 24 | Apr 28 | Jul 17 |
| Zone 7 | Feb 6 | Apr 10 | Jun 29 |
| Zone 8 | Jan 31 | Apr 4 | Jun 23 |
| Zone 9 | Jan 3 | Mar 7 | May 26 |
| Zone 10 | Dec 6 | Feb 7 | Apr 28 |
| Zone 11+ | Nov 20 | Jan 22 | Apr 12 |
Tight means first pick lands within two weeks of that zone's average first fall frost. It is doable, with zero slack in the indoor start.
Why not just use a bell
A bell pepper is blocky, thick-walled and mostly water. Blacken one and you fight the skin off in fragments while the flesh collapses. A Marconi is long, tapered and thinner-shouldered: it chars evenly over a flame, and after fifteen minutes covered the skin lifts away in one piece.
Fully red, it is also considerably sweeter than a red bell. In a romesco — where roasted pepper, almond and garlic are the entire recipe — that sugar is most of what you taste.
Growing
Standard sweet-pepper culture, with one caution: sweet peppers run into blossom end rot more readily than hot ones, and containers make it worse. Mulch the surface, water on a timer rather than by memory, and the problem mostly disappears.
Eighty days to red from transplant. Around 3.5 lb per plant — sweet peppers out-yield hot ones by weight because the fruit is so much larger.
Roasting for sauce
Char over an open flame or under a broiler until the skin is genuinely black — not brown, black. Transfer immediately into a bowl and cover for 15 minutes. The trapped steam separates the skin. Rub it off with your fingers; do not rinse under a tap, which washes away the roasted oils you just spent twenty minutes creating.
Peeled roasted peppers freeze extremely well in their own liquid, so a September glut becomes a February romesco.
How this crop actually fails
Named, specific, and in the order you're most likely to meet them.
Peppers picked green, and the sauce tastes thin and vegetal
Cause Marconi is a red pepper. Green it is an inferior bell with none of the sugar that roasting concentrates.
Fix Wait. Green to full red takes another two to three weeks and triples the sugar.
Black sunken patch at the blossom end
Cause Blossom end rot — inconsistent watering interrupting calcium transport, most common in containers.
Fix Mulch and water on a timer. Sweet peppers are more prone to this than hot ones.
Skin will not peel after charring
Cause Not charred hard enough, or not steamed after.
Fix Blacken the skin completely over flame or under a broiler, then seal in a covered bowl for 15 minutes. The steam lifts the skin; it should come off in sheets.
What marconi red pepper needs
Marconi Red Sweet Pepper Seed
A long Italian sweet pepper that roasts and peels far better than a bell. Romesco and any red-pepper paste wants this, not a supermarket bell.
$4.94Buy →
Organic Seed Starter Potting MixMust have
Seed-starting mix is not potting soil with a nicer label — it is finer, lighter, and low in nutrients on purpose, because a seedling's first roots want air and moisture, not fertiliser.
$15.82Buy →
Seedling Heat Mat + Digital ThermostatMust have
Peppers germinate on soil temperature, not air temperature. At 65 °F a habanero takes a month and half of them rot; at 85 °F it is up in eight days. The thermostat is the half that matters.
$27.89Buy →
T8 Full-Spectrum Grow Lights, 1 ft 4-packMust have
A south window in March delivers a fraction of the light a pepper seedling needs, and the plant tells you by stretching. Two inches of LED above the canopy for 16 hours a day fixes it permanently.
$38.69Buy →
5-Gallon Fabric Grow Bags, 5-Pack
Fabric pots air-prune roots and drain faster than a plastic pot can, which is the entire reason container tomatoes fail. Five gallons is the honest minimum for a pepper; a tomato wants ten.
$15.99Buy →
Ocean Forest Potting SoilMust have
Pre-charged with enough nutrition to carry a transplant for its first month without feeding, which is exactly the window when most container plants stall.
$25.99Buy →
Organic Tomato-Tone 3-4-6 with 8% CalciumMust have
The NPK ratio is the point: low nitrogen, higher potassium. Feed a tomato a high-nitrogen lawn fertiliser and you get a magnificent six-foot plant with four tomatoes on it.
$15.25Buy →
Rot-Stop Blossom End Rot Concentrate
Blossom end rot is almost never a soil calcium shortage — it is a calcium *transport* failure caused by inconsistent water. A foliar calcium spray buys time while you fix the watering, which is the real cure.
$8.99Buy →
6" Micro-Tip Pruning SnipsMust have
Ninety percent of sauce-garden cutting is snipping a pepper stem or a basil node, and a fine-tipped snip does it better than any pruner. Pulling peppers by hand tears the branch.
$12.89Buy →
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Sauces this plant is for
Last reviewed 2026-09-01. Numbers are cultivar-typical, not guarantees —tell us if yours ran different and we'll say so on the page.