Crop details

Pyrethrum

Tanacetum cinerariifolium

Family: Asteraceae

Quick stats

Family	Asteraceae
Typical harvest	0.9 t/ha
Varieties	3
Pests & diseases	6
Seasons	3

Crop profile

Growth habit	perennial
Days to harvest	365
Main uses	Dried flowers for extraction of natural pyrethrins used in insecticides; some cottage use as dried spray.
Pollination	insect
Origin / where it grows	Cool highland crop grown mainly in temperate and high-altitude tropical regions with reliable moisture and good drainage.

Weather, soil & spacing

Best temperature	12–22 °C
Rainfall	900–1300 mm/yr
Altitude	1500–2800 m
Best pH	6–7
Soil type	Deep, well-drained volcanic loams or loam soils with good organic matter and friable structure.
Row spacing	60 cm
Plant spacing	45 cm
Planting depth	1 cm
Seed rate	1 kg/ha
Nursery days	60

Simple notes for farmers

About the crop: This crop is perennial, which means once you plant it, the same plant can keep producing for many years. You can normally start harvesting about 365 days after planting, depending on care and variety.

Main use: Farmers mostly grow this crop for dried flowers for extraction of natural pyrethrins used in insecticides; some cottage use as dried spray..

Pollination: This crop is mainly pollinated by insect. Keeping flowers healthy and having insects like bees in the field helps improve fruit set and yields.

Where it grows: Cool highland crop grown mainly in temperate and high-altitude tropical regions with reliable moisture and good drainage. It is grouped under: Oil & Industrial.

Best climate: This crop does well in warm areas where the temperature is usually between 12 and 22 degrees Celsius. It prefers places that receive around 900 to 1300 millimetres of rain in a year. It can grow from near sea level up to about 2800 metres above sea level.

Soil: The crop grows best in slightly acidic to near neutral soils, with a pH of about 6 to 7. It does well in deep, well-drained volcanic loams or loam soils with good organic matter and friable structure.. Good drainage is important, so avoid waterlogged spots.

Plant spacing: Plant in rows about 60 centimetres apart, and leave about 45 centimetres between plants in the row. This gives each plant enough space for roots and canopy to spread.

Planting depth: Dig planting holes or furrows about 1 centimetres deep so the roots sit firmly in the soil but are not buried too deep.

Seed or planting material: Use around 1 kilograms of seed or planting material per hectare. Spread or plant evenly so the field has a good stand without being overcrowded.

Nursery period: If you raise seedlings in a nursery, keep them there for about 60 days before transplanting to the main field, when they are strong and healthy.

Farmer guide (mwongozo wa mkulima)

Planting: Raise seedlings in a cool, well-managed nursery or trays and transplant when 6–8 leaf stage. Plant in moist, well-prepared beds at correct spacing.

Transplanting: Transplant on a cool, cloudy day or late afternoon. Water seedlings well before lifting and after transplanting, and mulch around crowns.

Irrigation: Keep soil moist but not waterlogged, especially during establishment and spike/flower development. Avoid long dry spells which reduce flower yield.

Fertigation: Where drip is available, apply small, regular doses of N and K from early growth through peak flowering while avoiding lush, disease-prone growth.

Pest scouting: Scout for leaf spots, crown and root rots, aphids, thrips and caterpillars. Remove diseased plants promptly and maintain open, aerated canopies.

Pruning: Remove dead leaves and spent flower stalks to encourage new flowering shoots. Keep beds weed-free and avoid smothering crowns.

Harvest: Pick flower heads when fully open but petals still firm and white, before browning. Multiple pickings are done every few days during peak flushes.

Postharvest: Dry flowers quickly under shade or low-temperature dryers to preserve pyrethrin content and colour. Store dry flowers in cool, dry, well-ventilated conditions in breathable bags.

Nutrient schedule (mbolea kwa hatua)

#	Stage	DAP	Product	Rate	Targets (kg/ha)	Notes
1	Basal at planting/transplanting	0	NPK 17-17-17 + compost	150 kg/ha (plus 5–8 t/ha compost)	N: 26, P₂O₅: 26, K₂O: 26	Band or broadcast and incorporate into topsoil before transplanting seedlings.
2	Early growth topdress	45	CAN 26% N	100 kg/ha	N: 26, P₂O₅: 0, K₂O: 0	Apply around plants on moist soil, then lightly earth up or mulch.
3	Flowering/flush support (optional)	120	NPK 20-10-10 or similar	70 kg/ha	N: 14, P₂O₅: 7, K₂O: 7	Apply after a heavy picking flush or at start of main flowering season in high-producing fields.

Nutrient requirements

Nutrient	Stage	Amount	Unit
N	Basal	40	kg/ha
P₂O₅	Basal	30	kg/ha
K₂O	Basal	30	kg/ha
N	Early_growth	30	kg/ha
P₂O₅	Early_growth	0	kg/ha
K₂O	Early_growth	20	kg/ha
N	After_harvest_flush	20	kg/ha
P₂O₅	After_harvest_flush	0	kg/ha
K₂O	After_harvest_flush	30	kg/ha

Name	Country	Maturity	Traits
Highland pyrethrum selection	KE	365	High pyrethrin content, suited to cool highland zones with regular picking.
Early-flowering pyrethrum type	TZ	330	Earlier establishment and flowering for shorter cool seasons.
Local pyrethrum landrace	UG	360	Adapted to highland homestead plots, used for local insecticidal preparations.

Stage	Product	Rate (kg/ha)	Notes
Basal	NPK 17-17-17 + compost	150	Apply before or at transplanting with 5–8 t/ha compost or well-rotted manure.
Early growth	CAN 26% N	100	Apply 6–8 weeks after transplanting when plants are well established.
After heavy pick	NPK 20-10-10	70	Light dressing after a major flowering/picking period in intensively managed fields.

Name	Type	Symptoms	Management
Aphids	pest	Colonies on young shoots and flower stalks, sticky honeydew and sooty mould; distorted growth.	Encourage natural enemies, avoid heavy nitrogen that favours aphids, and spot-manage severe patches where necessary.
Thrips	pest	Silvery patches and speckling on leaves and flower heads, deformed petals and reduced flower quality.	Maintain good field hygiene, avoid excessive dust and moisture stress, and monitor flower heads during peak flushes.
Cutworms and soil insects	pest	Seedlings cut at base or missing plants in newly transplanted fields.	Well-prepared, weed-free beds before transplanting; where severe, spot treatments and replanting of affected gaps.
Leaf spots / blights	disease	Brown or dark lesions on leaves, sometimes with yellow halo; premature leaf senescence.	Improve airflow with correct spacing, avoid overhead irrigation late in the day, and remove heavily infected debris.
Crown and root rots	disease	Yellowing and wilting plants, rotted crowns or roots in wet patches; plants easily pulled out.	Ensure well-drained soils, avoid waterlogging, raise beds in heavy soils, and remove dead plants promptly.
Powdery mildew (cool, humid periods)	disease	White powdery growth on leaves and stems, reduced vigour and flowering in severe infections.	Maintain open canopies, avoid overcrowding and excessive N, and remove heavily infected plant parts.

System	Typical	Min	Max	Notes
Low-input rainfed (dried flowers)	0.4	0.2	0.6	Smallholder fields with limited fertilizer and irregular picking; yields spread over many pickings.
Managed highland (dried flowers)	0.8	0.5	1	Improved varieties, balanced NPK and good weed control; regular picking during flowering peaks.
Intensive well-fertilized (dried flowers)	1.5	1	2	High plant density, good nutrition and moisture, and careful harvest/handling for industrial extraction.

Country	Region	Planting	Harvest
KE	Cool highlands (e.g. Rift highlands, high elevation zones)	At onset of long or short rains in cool highland zones, avoiding very hot or extremely wet periods.	Light picking may start 6–8 months after transplanting; main picking cycles continue for several years while stands remain productive.
TZ	Northern and southern highlands	Start of cool rainy season in highland areas with good drainage.	Multiple picking flushes through cool, relatively dry periods once plants come into bearing.
UG	High altitude belts with cool temperatures and reliable rainfall	At onset of main rains in highland communities growing pyrethrum.	Perennial picking cycles with peaks during cooler, drier spells each year.

Country	Region	Suitability
KE	Rift Valley and other highland zones above ~1,800 m with cool climates	High
TZ	Northern and southern highlands with cool, moist conditions	High
UG	Highland belts around key upland districts with cool temperatures	High