Chicory / Italian chicory (Cichorium intybus) growing guide

Quick facts

Category: leafy greens
Difficulty: intermediate
Days to harvest: 60 to 90 days
Harvest type: continuous production over weeks or months
Spacing: 25 cm between plants

Environment

Temperature: 7–22°C
pH: 5.5 to 7
EC (hydroponic): 1.2 to 2 mS/cm
Daily light: 12 to 18 mol/m²/day

Climate and zones

USDA zones: 3 to 10 (winter low around -40°C or warmer)
Frost tolerance: frost hardy (handles regular frost)
Season: cool (spring and fall crops)

Viable growing environments:

outdoor year-round (in zone)
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

Chicory works in:

deep water culture (rafts)
NFT channels
media bed (ebb and flow)
wicking bed
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 (chicory works in the media listed below).

Medium	pH effect	Water retention	Bacterial surface
Rockwool (Mineral wool)	alkaline until pre-soaked	very high	low
Coco coir (Coconut coir)	slightly acidic	high	moderate
Perlite (Expanded volcanic glass)	neutral / inert	very low	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	0.8
vegetative	3	1	2	1.6

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

Multiple chicory types suit different hydroponic approaches. For radicchio: EC 1.5-2.5 mS/cm, pH 6.0-7.0, temperature 12–20°C. Grows similarly to lettuce but slower (70-90 days from transplant). The red coloring intensifies in cool conditions. For Belgian endive (witloof): a two-phase process. First, grow the roots (like growing turnips, 90-100 days). Then dig the roots, trim the tops, and force them in total darkness at 12–15°C in moist sand or a hydroponic forcing chamber. New pale, tightly wrapped heads emerge from the root crown in 3-4 weeks. The forcing step is what makes Belgian endive special and expensive ($8-15/kg retail). For sugarloaf and catalogna: culture similar to radicchio but with different harvest timing. All chicory types tolerate cool temperatures well and perform as fall/winter hydroponic crops. The bitter flavor is milder in cool-grown plants and more intense in warm conditions. Chicory is a high-value specialty crop for growers serving European restaurants or farmers' markets with adventurous customers.

Notable varieties

A starting shortlist of cultivars worth knowing about. Not exhaustive: the seed catalogs list hundreds of named varieties. These are the ones home growers commonly choose between.

Cultivar	Type	Days	Notes
Chioggia Radicchio	open-pollinated	85	Round red head, white-veined. The classic Italian radicchio sold in produce sections worldwide. Needs cold-snap to fully colour up; spring-planted heads tend toward green or pink rather than deep red.
Treviso Radicchio	open-pollinated	90	Elongated head, like a small red Romaine. Slower than Chioggia and pricier in markets. Grills exceptionally well; caramelizes the bitterness.
Pan di Zucchero (Sugarloaf)	open-pollinated	75	Light-green Cos-shaped head, the mildest chicory in this list. Crisp inner leaves are nearly lettuce-like. The gateway chicory for people who think they don't like chicory.
Witloof (Belgian endive)	open-pollinated	120	Grown for the root the first year, then lifted, trimmed, and forced in dark warm conditions to produce the white blanched chicons. A two-stage crop that takes more effort than other chicory types but the result is the pricey 'endive' of fine dining.