New Guinea Impatiens Propagation

New Guinea Impatiens Propagation

New Guinea Impatiens (NGI) are relatively easy to propagate. Providing the appropriate cultural conditions is the key to successful root system development. In North America, most NGIs are propagated during late fall and early winter when light intensities are low enough that additional shade is not required. These same low light, cool temperature conditions impact the speed of rooting and create conditions favorable to insects or diseases that may attack the crop. Starting with good quality cuttings from reliable suppliers is your best defense for preventing problems.

CULTURAL REQUIREMENTS

Media
Choose a sterile, well aerated propagation media. Mixes that are predominately peat moss tend to hold too much water and should be avoided or blended with other components to yield a more favorable propagation medium. Inorganic media, such as Oasis® or Rockwool®, work equally well.

Bottom Heat
Bottom heat is an important factor in promoting healthy root development. Provide media temperatures of 70-75°F/21-24°C for best results. Monitor root zone temperatures frequently as the application of mist may cool the media and slow root development.

Rooting Hormones
The use of rooting hormones is optional as most NGI cultivars root easily without them. However, not all cultivars respond equally in propagation, and use of these hormones can be beneficial if rooting a number of different cultivars. Liquid or powder formulations work well when used at rates suggested for herbaceous plants.

Temperature Management
Provide air temperatures of 68-72°F/20-22°C at night and 70-80°F/21-26°C during the daytime.

Mist Application
Mist applications on NGIs should provide adequate moisture to prevent wilting of cuttings, yet allow cuttings to stay dry enough to avoid rot. Treat these plants as you would geranium cuttings when setting mist clocks. The most common cause of rot in young NGI cuttings is overmisting, which can result in Botrytis and other fungal diseases.

 TROUBLESHOOTING IN PROPAGATION

PROBLEM: Cuttings rot in propagation

POTENTIAL CAUSE:
Diseases: Botrytis (can result from damaged cuttings or cuttings with open flowers), Myrothecium (leaf spot), Rhizoctonia (maybe the result of contaminated rooting media) or Erwinia
Cultural: Excess mist application
Other: Rot beginning at the base of cuttings and moving upward may indicate rooting hormone was not properly diluted.


PROBLEM: Leaves curl downward, making it difficult to plant cuttings

POTENTIAL CAUSE:
Cultural: Cold temperature or DIF in propagation causes leaves to reflex downward and hold cuttings above the rooting media
Other: Cuttings may have been harvested from stock plants treated with Florel®
resulting in a downward leaf presentation similar to plants exposed to DIF.


PROBLEM: Cuttings fail to develop roots

POTENTIAL CAUSE:
Insects: Fungus gnat larvae may be feeding on the tender new roots as they form
Cultural: Rooting media temperature is too cold, may be aggravated by excess mist application
Other: Cuttings may have been harvested from stock plants under stress, affecting the performance of these plants.

We hope the information provided will be helpful. It is based upon data and knowledge (including information provided by the recipient) considered to be true and accurate, but without independent investigation and is offered for the recipient’s consideration, investigation and verification, but we do not warrant the results to be obtained. Please read all statement, recommendations, or suggestions in conjunction with any conditions of sale or use which apply to any products, or systems recommended by us. No statement, recommendation, or suggestion is intended for any use which would infringe any patent/copyright.

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