Culture Report: Dahlia 'Sincerity'

There are three words to describe 'Sincerity' dahlia: Big, bold and beautiful. Dense, naturally well-branched plants make the perfect backdrop for the showy blooms. 'Sincerity' is a picture-perfect choice for the landscape and high-end patio containers. Give it a try with these easy culture tips.

PROPAGATION

Stick cuttings into 105-cell propagation trays or larger. Expect root emergence in eight to 10 days. Rooting hormone is not recommended, but bottom heat for the first three weeks will help ensure even, strong rooting.  Media temperatures of 70 to 74° F are recommended and then low them to hold and tone cuttings. Air temperatures between 72 to 74° F during the day and 70 to 72° F at night are recommended.

Apply enough mist upon stick to rehydrate the cuttings and keep them from wilting — they should rehydrate within 24 hours. Cuttings that are allowed to wilt heavily after stick will callus unevenly and delay rooting. CapSil (spray adjuvant) can be sprayed on the cuttings at 2 to 4 oz. /100 gal within one to two days of sticking to help rehydration. Misting can be reduced after cuttings have rehydrated.

Dahlias are facultative short day plants so during propagation it is important to provide long days (14 hours) either through day length extension or night interruption to prevent premature budding that can delay rooting. For the first two weeks after sticking or until roots form, a daily light integral (DLI) of 4 to 6 mols/ day is recommended and then light levels can be increased to greater than 12 mols/day. 'Sincerity' should be fully rooted in about four weeks in a 105-cell tray.

Recommended media pH and EC is 5.8 to 6.2 and 1.4 to 2.0, respectively (via PourThru method). Fertilization should begin at 100-ppm nitrogen when roots become visible. Rates can be increased up to 200-ppm nitrogen after roots are well developed. It's best to use primarily Cal-Mag Plus (calcium nitrate + magnesium nitrate) fertilizers in propagation to prevent unwanted stretch. Pinching is usually not needed and not advised.

'Sincerity' has a moderately vigorous habit and may require a PGR treatment in propagation to reduce unwanted internode elongation. If needed to control growth after rooting, sprays of B-Nine WSG (1,500 ppm) are usually sufficient. A tank-mix spray of Florel (350 to 500 ppm) + B-Nine WSG (1,500 ppm) can also be used to control growth and further improve branching. Do not spray Florel on stressed or weak cuttings. For all sprays listed above, the mist should be off for a minimum of one hour for the PGR to absorb into the leaf tissue.

FINISH

Transplant directly into the finished container. We recommend one plant per pot in a gallon (2.5 quart) container; for larger containers, such as 10- or 12-inch pots, use two to three plants per pot. Plant the liner relatively deep in the container. Dahlias need deep and sturdy planting to provide good support and balance in the pot for the maturing plants.

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Photo Courtesy of Greenhouse Product News

Source: Greenhouse Product News