Ageratum Blue Horizon Grower Fact

Ageratum Blue Horizon

Cultural Information for:

Ageratum Blue Horizon

Common Name:

Ageratum or Floss Flower

Botanical Name:

Ageratum houstonianum

Seed Count:


Optimum Germination Temperature:

77 oF / 25 oC

Optimum Growing Temperature:

65 F / 18 C

Plug Stage C 288 plug cell - 5 weeks
Stage One (days 1-7) Single sow pelleted seed into a well mdrained peat mixture with a pH of 5.8-6.2 and a low nutrient charge (E.C. < 0.5 mmhos/2:1 slurry). Ageratum requires light to germinate so lightly cover with coarse vermiculite and maintain sufficient moisture to melt the pellet. Optimum germination temperature is 78-82 F/25-28 C.

Stage Two (days 8-20) After seed emergence move plug trays to a greenhouse with high light and good air circulation. Reduce air temperature to 60-70 F/16-21 C and apply a light feed of 50-75 ppm Nitrogen using a well balanced calcium nitrate based formulation.

Stage Three (days 21-30) Increase fertilizer level to 100- 150 ppm N. Optimum E.C. is 0.7-1.0 mmhos (2:1 slurry). Allowing the plants to dry slightly in between watering will reduce stretch and promote a strong and well toned plant. Growth regulation is not recommended for cut flower production. For ornamental use in containers where height control is desirable, B-9 (Alar) at 2,500 ppm is effective.

Stage Four (days 31-35) The plugs are approaching transplant stage. Reduce fertilizer to tone the plants and prepare them for transplanting. Do not delay transplanting.

Cut Flower Culture:
Media: Select a well drained sterile cut flower bed in full sun with a pH of 5.8-6.2 and a low nutrient charge.

Watering: Initially, keep the plants well moistened and then water as needed. Growing too dry may result in red-edged or yellow leaves.

Fertilizer: Well balanced calcium nitrate based formulations work well to build strong and healthy plants. Optimum E.C. is 0.7- 1.0 mmhos. Avoid excess nitrogen as it promotes overgrowth, invites disease and reduces vase life.

Lighting: Optimum light level is up to 7,000 foot candles/ 75,000 lux. Whitewashing the glass may be necessary May-September to reduce light intensity. Extending the photoperiod in winter to 16 hours is recommended to ensure sufficient stem length and improve flower quality.

Temperature: Optimum temperature is 60-70 F/16-21 C. For winter production maintain 60 F/15 C maximum. Temperature is more important than day length for winter flowering. Under low light conditions do not grow too warm, (above 60 F/15 C), or else the stem quality will be reduced and tissue too soft.

Insects: Aphids, White Fly, Thrips, Mites

Single Stemmed Culture: Space plants 4 x 4 inches/10 x 10 cm. apart in beds and provide support netting. Raise netting as the plants grow. Do not pinch the plants.

Multiple Stemmed Culture: Space plants 8 x 8 inches/20 x 20 cm. apart and pinch the growing tip to induce side branching. This will result in a heavy crop of high quality cut flowers.

Harvesting: For summer production allow 12 weeks from sowing and 15 weeks for winter production. The first flower is usually removed to create a flush of flowers. The flowers should be well-colored before cutting.

Container Culture:
Pots: For green sales in 4 inch/10 cm. pots place one plant per pot and plan on 4 weeks from transplant to shipping. Larger containers in color require 6-7 weeks from transplant.

Media: Select a well drained sterile mixture with a pH of 5.8-6.2 and a low nutrient charge.

Growth regulation: B-9 (Alar) is effective at 2,500 ppm.

Culture watch points: Avoid using Kelthane or Ortocides on the crop. Ronilan damage seedlings.
Do not apply plant growth regulators during bud formation.