Guajillo
Capsicum annuum
Also known as: Mirasol (fresh form), Chile guajillo, Travieso
Quick facts
- Category
- fruiting
- Difficulty
- beginner
- Days to harvest
- 80 to 100 days
- Harvest type
- continuous production over weeks or months
- Spacing
- 50 cm between plants
Environment
- Temperature
- 18–30°C
- pH
- 6 to 6.8
- EC (hydroponic)
- 1.8 to 2.6 mS/cm
- Daily light
- 22 to 30 mol/m²/day (strict, will fail outside this range)
Climate and zones
- USDA zones
- 5 to 12 (winter low around -29°C or warmer)
- Frost tolerance
- frost sensitive (dies at first frost)
- Season
- warm (summer crops, frost-sensitive)
Viable growing environments:
- outdoor in growing season (annual)
- unheated greenhouse / hoop house
- heated greenhouse
- indoor (heated home)
- indoor hydroponics under grow lights
USDA zone bounds reflect outdoor year-round survival. Anywhere outside the bounded zone range, this crop still grows as an annual in the warm months (outdoor_seasonal), under cover (greenhouse), or indoors under lights.
Growing systems
Guajillo works in:
- drip / Dutch buckets
- media bed (ebb and flow)
- soil bed
Growing media
The substrate the roots sit in. Choice depends on the system (clay pebbles don't fit NFT channels; rockwool isn't used in media beds) and the crop (guajillo works in the media listed below).
| Medium | pH effect | Water retention | Bacterial surface |
|---|---|---|---|
| Expanded clay pebbles (LECA) | neutral / inert | low | high |
| Coco coir (Coconut coir) | slightly acidic | high | moderate |
| Perlite (Expanded volcanic glass) | neutral / inert | very low | low |
| Rockwool (Mineral wool) | alkaline until pre-soaked | very high | low |
| Soil-based mix (Potting soil) | varies by source | high | high |
Bacterial surface area matters for aquaponics: clay pebbles, lava rock, and pumice double as biofilter substrate. Low-surface media (rockwool, perlite, pea gravel) work in hydroponics but need a separate biofilter in aquaponics.
Nutrient demand by stage
NPK ratios are relative weights at each growth stage; the nutrient mix calculator scales them to absolute grams or ml. EC targets shift through the plant's life: seedlings need a much lighter solution than fruiting adults.
| Stage | N | P | K | EC target (mS/cm) |
|---|---|---|---|---|
| seedling | 2 | 1 | 1 | 1.2 |
| vegetative | 3 | 1 | 2 | 1.8 |
| flowering | 1 | 2 | 3 | 2.2 |
| fruiting | 1 | 2 | 3 | 2.4 |
Companion-growing notes
- Heavy uptake of potassium, calcium. Co-grown crops with the same demand will end up deficient even at "correct" EC. Plan around this in shared reservoirs.
Aquaponics suitability
Compatible with typical aquaponics nutrient profiles. Fish waste provides enough nitrogen for healthy growth; supplemental potassium, calcium, and iron may still be needed depending on fish stocking density.
Care notes
A productive hydroponic pepper for growers who make Mexican sauces. EC 2.0-3.0 mS/cm. pH 5.8-6.5. Temperature: 20–30°C. High light (DLI 18-25 mol/m2/day). Plants are medium-sized (60–80 cm). From transplant to red-ripe fruit: 80-95 days (the peppers must be fully red-ripe before drying). Each plant produces 20-30 peppers over a season. Harvest when fully red and beginning to dry on the plant. For proper drying: dehydrate whole at 55–65°C until leathery but still pliable (not brittle; properly dried guajillos should be flexible). Alternatively, string whole peppers and hang in a warm, dry, well-ventilated area for 2-4 weeks. Store dried in sealed containers for 12+ months. To use: remove the stem and seeds, toast briefly in a dry pan until fragrant (30 seconds per side), soak in hot water for 20-30 minutes, then blend into a smooth sauce. Homegrown guajillo has a brighter, more complex flavor than the sometimes-stale dried chiles available at retail. Calcium supplementation during fruiting prevents blossom end rot.
Verified against: chile-pepper-institute-nmsu, instituto-nacional-de-investigaciones-forestales-agricolas-y-pecuarias-mexico, u-of-arizona-cooperative-extension. Last reviewed 2026-05-15.