Growers

Crop Production Info

Dahlias as Pot and Container Plants

Crop Production (Page 2)

Light:

Dahlias require medium to high ( > 2500 foot candles) light intensities and grow best exposed to full sunlight. Reduced light conditions and tight spacings can produce tall and weak plants, even after the use of a PGR.

The earliest flowering pot dahlias are best produced under increasing natural daylengths of 10 to 14 hours. Shorter days (<8 hour photoperiod) will prevent or delay flowering, whereas long days (4 hour night break) have little effect on plant quality.

Temperature and Timing:

Greenhouse forced dahlias should be grown at 60 to 65 F night and 70 to 75 F day temperature. Maintain lower night temperature during the entire crop cycle and avoid day temperatures to rise above 80 F. Near marketing day, crop development can be delayed by lowering night temperature to 55 F.

Under average conditions in early spring; Gallery dahlias take 8 weeks, and most Cactus and Decorative varieties 10 to12 weeks, to reach market stage. From bud stage to opening of the flower the average development time is; 14 days - 0.5 inch flower bud, 7 days - 0.75 inch flower bud, and 4 days - 1.0 inch flower bud.

Outdoor culture can start after the danger of frost, in a wind protected area. For outdoor culture, in full sunlight and cool night temperatures, the PGR requirements of potted dahlias will be lower. A summer crop does require shade and is recommended to be grown on a cool surface, no black top/cloth.

Pinching:

An early shoot pinch is very effective to produce compact, full and densely foliated plants with the maximum number of flowers per pot. Do not pinch to late, much initial growth will be lost and crop time will increase.

Each cultivar will produces a range of single, double and multiple shooted plants. For all cultivars we recommend to pinch those plants which produce only one single shoot. The optimal stage of development to pinch out the terminal shoot is after the 3rd or 4th pair of full grown leaves has developed. On double shooted plants the strongest dominant shoots also can be pinched. Plants with 2 or 3 shoots developing equally, do not have to be pinched.

Not all plants and cultivars reach the proper pinching stage at the same time, so make pinching a routine during the early crop stage. Cultivars do respond differently to pinching. Most selected varieties will force several lateral breaks from a pinched shoot, producing enough foliage to fill out the container surface. Some varieties, like Dinnerplates, only produce 1 break and maintain a strong horizontal growth, making the pinching less effective.

For large containers use pinch to balance plant growth to container size; a total of 4-6 initial shoots per 8" pot. Often 1 general pinch of all true dominant shoots in the entire crop will be enough to produce a quality container.

Dahlia Grow Info (roots)Dahlia Grow Info (pots)Dahlia Grow Info (pinch)

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