Poinsettia Maren Rooted Cutting Liner

For best results with Maren, grow one plant per 4- or 6-inch container, or three to five per 8- or 10-inh container. Use a porous peat-based soil with good drainage, a pH of 5.8-6.4, and constant liquid feed at 225-250 ppm N for dark-leaf varieties or 250-275 ppm N for medium-green leaf varieties. At first, use up to 30% total N as ammonium and reduce to 15% by end of September if leaf expansion is good. Use a 20-10-20 fertilizer plus Molybdenum or a 20-5-19 Poinsettia formulation and alternate with a 14-0-14, 15-0-15, 13-2-13, 14-4-14, or 15-5-15 from mid-October to November 1. This feeding program will encourage soft, lush growth and larger plant size. Alternatively, encourage more toned growth and smaller foliage early on by using a 17-5-17 or 15-5-15 Cal-Mag fertilizer. Switch to a high-nitrate containing fetilizer for the last two weeks before maturity to produce sturdier plants with better keeping quality. If you add Molybdenum to basic 20-10-20, create a stock at 3.2 oz Mo/1 gallon water and add 1.5 oz stock/10 gallons tank fertilizer. Maintain an EC of 1.5 mS/cm (SME) for the first few weeks after transplanting, then 2.0-2.5 mS/cm for medium-green varieties or 1.5-2.0 mS/cm for dark-leaf varieties. Gradually reduce feed by about 75% after November 10 and give two strong clear-water leaches before shipping. 

Pinch once, two to three weeks after transplant, leaving four to nine leaves, depending on finished container size. Remove premature stocks from the bottom nodes. 

Water regularly to avoid drastic changes in moisture, irrigating when the soil is just beginning to dry. Water stress can cause serious long-term problems with Poinsettia. Allow leaching from the bottom of each pot to prevent fertilizer buildup, and be careful not to get water on the bracts and leaves.

Provide vegetative long days and eliminate light pollution at night, which otherwise delays and disrupts flower initiation. New transplants benefit from light shade (3,000-3,500 fc) for 4-5 weeks and then full sun two weeks after being pinched. Shade is important for hot southern climates where Poinsettias start vegetative growth in August heat. Provide temperatures of 80 degrees daytime and 68 degrees nighttime during vegative growth, and then decrease temperatures to 78 degrees daytime and 65 degrees nighttime once flowers initiate in mid-late September, until Poinsettia is ready for sale. Excellent ventilation is crucial for keeping plants cool.

Proper spacing is essential for the shape and strength of each plant; space plants when the branches begin to touch. 

Watch for whiteflies, fungus gnats, botrytis, powdery mildew, bacterial soft rot, pythium, and rhizoctonia. Keep humidity below 75% to combat some of these diseases and maintain good airflow in the greenhouse. 

Use PGRs as needed, relying first on consistent day and night temperatures to control height. Cycocel and B-Nine tank mix or Bonzi spray work well as height control before flower initiation.

This variety has unique pink bracts. To grow Poinsettias with consistent bract coloration, provide even heat distribution, regular watering, and good circulation, and eliminate nighttime light intrusion.

Pinch once, two to three weeks after transplanting rooted cuttings into their final containers. Remove premature stocks from the bottom nodes. Pinch at seven nodes for six fully developed branches in 6-inch pots. For 4-inch pots, pinch on four or five leaves. For large containers, pinch on seven to nine nodes, adjusting for the final number of bracts needed to fill the pot. Provide light shade for two weeks after pinching and then provide full sun. 

Space containers when the branches begin to touch to help them grow in an upright, v-shape. Early spacing causes more horizontal growth and more breakable stems, while late spacing can cause a risk of disease and weak, leggy plants. In general, space 6-inch containers on 15" centers and 8-inch containers on 25" centers. While final spacing depends on cultivar and target size, 4-inch containers need slightly less space, and 10-inch containers may need more. Some cultivars are well-suited for high-density bench production.

PGR needs vary among Poinsettia varieties. Rely first on consistent day and night temperatures to control height. Pay attention to the relative vigor of the varieties you grow and monitor rapid-growing phases. When daytime temperatures exceed nighttime temperatures by more than five degrees in Northern climates, use Cycocel growth regulator treatment at 750-1,000 ppm one to four times after pinching. With daytime temperatures above 80 degrees and nighttime temperatures above 70 degrees, the plants will need more PGR; spray Cycocel (1,000 ppm) plus B-Nine (1,500 ppm) tank mix one to three times during the one to four weeks after pinching. Alternatively, use a Florel spray at 500 ppm three to five days before pinching, three to five days after pinching, and again three to five days later for vigorous varieties. Don't use Cycocel, B-Nine, or Florel after flower initiation. 

You may use micro drenches of paclobutrazol after flower initiation and before 50% color at 0.05-0.1 ppm. The higher rate is for vigorous varieties for moderate growth control. The lower rate is for medium vigor varieties for slight slowing of growth. Total accumulated Bonzi drench shouldn't exceed 0.25 ppm until bracts are at least 50% colored to avoid delaying color and reducing bract size. Consistently drench each container with 1 fl. oz/1 inch pot diameter. Apply a final Bonzi drench 3-4 weeks before finishing at 0.5-1.0 ppm in the North and 1-2 ppm in the South. 

If the crop is below the target height, early sprays (up to mid-October, at the beginning of color development) of gibberelic acid at 2-3 ppm can encourage 2-4 inches of growth within 2 weeks after application. Don't spray gibberelic acid late as it leads to undesirable bract shape and internode stretching. 

It's always best to conduct small-scale trials before doing large-scale applications of less traditional Poinsettia PGRs like mid-season Bonzi drenches and gibberellic acid. 

Scout for thrips, spider mites, shore flies, whiteflies, and fungus gnats as part of your commercial greenhouse's Integrated Pest Management program. 

Fungus Gnats are small, dark flies that lay eggs in damp soil where larvae feed on plant roots, causing damage and death. Watch for adult gnats flying around the plants and check for larvae in the soil. Prevent infestations by allowing the soil to dry between waterings and controlling humidity in the greenhouse. Fungus Gnats thrive in moist conditions. Catch adult gnats with sticky traps to prevent them from laying eggs. Use beneficial nematodes or apply Bacillus thuringiensis.

Whiteflies are small, winged insects that eat plant sap and cause yellowed leaves and stunted growth. Severe infestations can lead to plants dying. Prevent infestations by sanitizing surfaces and tools and removing debris. Introduce natural predators and use sticky traps to control populations. Insecticidal soaps and oils are also effective against this pest.

Thrips are tiny insects that eat plant tissue and can transmit viruses. Watch for silvery-white streaks or black spots on foliage and distorted growth. Use natural predators (like predatory mites), insecticidal soap, neem oil, and sticky traps to control infestations and prevent spread. 

Spider Mites are tiny pests that cause stippling, yellowing, and webbing on foliage by feeding on plant sap. They flourish in warm, dry environments. Use correct water and fertilizing practices; over-fertilizing can attract spider mites. Proper humidity levels, predatory mites or ladybugs, and insecticidal soaps or oils may prevent or address a spider mite infestation.

Shore Flies are small black flies attracted to algae and organic matter. Watch for adult flies around plants and larvae in the soil. Sanitize surfaces and prevent algae growth in your greenhouse. Remove any extraneous organic matter, use sticky traps to catch adult flies, and use beneficial nematodes to kill larvae. 

Watch for signs of pythium rot, botrytis, powdery mildew, rhizoctonia, and scab. The best treatment for disease is prevention. Sanitize surfaces, tools, and equipment before use and use sanitary growing media and containers. Water at the base of each plant and provide good airflow and adequate spacing in your greenhouse. 

Pythium and Rhizoctonia are fungal diseases that cause stunted growth, yellowed leaves, and plant death by eating away at the plant's roots. Use well-draining planting media and provide good airflow and spacing in your greenhouse. Allow the soil to dry slightly between waterings and apply fungicides with active ingredients abamectin, spinosad, or imidacloprid to combat these diseases.

Powdery Mildew is a fungal disease that thrives in humid conditions, appearing as a white or gray coating on foliage and flowers. Provide good airflow in your greenhouse. We recommend horizontal airflow fans to help control humidity levels alongside a dehumidifier or manual venting. Remove and destroy infected plants and apply fungicides as needed or preventatively. Look for the active ingredients myclobutanil, trifloxystrobin, or potassium bicarbonate to combat Powdery Mildew threatening your seedling plugs.

Botrytis is a common fungal disease that causes brown spots on stems, leaves, and flowers. Remove and destroy affected plants, maintain appropriate humidity levels, and apply fungicides with boscalid, fenhexamid, or iprodione to control the spread. Water plants in the morning and allow the soil to dry slightly between waterings.

Scab periodically appears in Poinsettias as raised, bleach-white scab-like lesions on stems and leaves and excessive elongation of infected stems. Control and prevent with a spray of Mural at 4-7 oz/100 gallons or Eagle 20EW fungicide at 8 oz/100 gallons. Rotate in products containing mancozeb to prevent scab.

We recommend growing one rooted plug per 4- or 6-inch container or three to five per 8- or 10-inch container. Use a porous peat-based soil with good drainage and bury the ellepot level with the soil, evenly spaced or centered in the container. Use a drench of a fungicide containing thiphanate-methyl to prevent fungal root diseases. Pinch two to three weeks after transplant. Provide light shade for new transplants for four to five weeks, especially in the south.