August 2002

Hello! Dahlia By Martyn Phillips

With the new Hello! Dahlia, you can say goodbye to pastproblems associated with seed dahlia, including double-sowing to avoid low andinconsistent germination rates. Hello! offers exceptional germination rates,excellent seed uniformity and is easy to produce as a bedding plant or as apremium, potted product.

Germination

Sow Hello! in 288-count or larger plug trays; it is notnecessary to provide light for germination. Cover seeds lightly with coarsevermiculite to maintain moisture levels. Media should barely be moist to thetouch or one on a scale of one to five, with one being nearly dry and fivebeing saturated. Media EC should be 0.5-0.75, pH should be 5.5-5.8 andtemperature should be 68-73¼ F.

Once the first true leaves begin to emerge, the media shouldbe allowed to dry to the touch between waterings. At this point, thetemperature can be lowered slightly to 65-70¼ F, and fertilization canbegin at 50-75 ppm nitrogen using a calcium-based fertilizer. Fertilization canbe increased to 100-150 ppm nitrogen when the roots are penetrating the plugcell and the second set of true leaves is present. If necessary, B-Nine can beapplied at 750-1,500 ppm in the plug tray. When the roots hold the plug masstogether easily and there are at least 2-3 sets of true leaves, Hello! is readyto transplant.

Growing On

Hello! shows best in 4- to 5-inch pots. Select a porous,well-drained media and plant plugs somewhat deep to produce a more stableplant. Media pH should be 5.8-6.2. Maintain moderate moisture levels whilecontinuing to allow media to dry to the touch between waterings. Do not let theplants wilt; too little water will produce small plants. Using a completefertilizer with micronutrients, constant liquid feed at 150 ppm nitrogenmaintaining a media EC of 0.8-1.0. After transplant, temperature can be raisedslightly to 68-72¼ F for 10 days to stimulate root development. Afterthese 10 days, the temperature can be lowered slightly to 65-70¼ F.Temperatures below 62¼ F will slow plant growth and produce more compactplants, while temperatures above 80¼ F will inhibit flower initiation.

Other Must-Knows

Light. It isextremely important to note that dahlias want to form tubers under short days.This makes it necessary to provide night interruption lighting or extend daysto 12-14 hours in order to suppress tuber formation.

PGRs. Hello! has excellent natural branching, and nopinching is necessary. If necessary, Hello! responds to B-Nine at 750-1,500ppm.

Pests/Diseases.Thrips, red spider mites, whitefly, aphids and leafminers are sometimes foundon dahlia. Botrytis, mildew and Tomato Spotted Wilt Virus are also occasionallyfound with dahlia.

Scheduling. A cropof Hello! in 4- to 5-inch pots can be produced in 9-12 weeks. Plug crop time is3-4 weeks, and a 4- to 5-inch crop can be finished in 6-8 weeks fromtransplant.

Hello! comes in six separate colors and a mix. Colorsinclude White, Yellow Shades, Bronze Shades, Scarlet Shades, Rose Shades andPink Shades.