USE OF ANCYMIDOL (A-REST^TM) FOR POTTED TULIPST

General Aspects

There are three functional uses for ancymidol on potted tulips. One is to control total plant height at the time of marketing. Ideally, the 16 inch pot tulip should be 10-12 inches tall at this stage of development. Height regulation is accomplished primarily through the reduction in length of the lower most tulip stem internodes. A second use is control of the tulip stem post-flowering elongation. In this case, the growth of most of the internodes is reduced. Lastly, through reduced elongation of internodes, incidence of stem topple and sometimes flower blasting can be minimized.

The initial length of the plants when they are placed under greenhouse conditions is critical. Shoots should be approximately 1-4 inches long. Five inches is maximum. This is important because the chemical cannot reverse stem growthwhich has already taken place. Thus, the proper programming procedures are imperative. Also important: ancymidol is less effective in the dark than in light. Therefore, it must be applied in the greenhouse.

When proper programming and application procedures have been used, ancymidol does not have an effect on: (1) timing of properly programmed tulip cultivars, (2) uniformity of flowering within a pot, (3) percentage of plants flowering, or (4) flower size. The only marked effect is a reduction in the elongation of the internodes of the tulip scape.

Because there are differences in cultivar responses to the growth retardant, the exact programming procedures and planting media used by bulb forcers, all first time users are urged to try ancymidol on only a portion of their crop. Allcultivars should be tested. This will serve to familiarize forcers with the chemical's use on tulips and to establish the exact rates and application time under their forcing conditions.

Medium and Application Techniques

The composition and pH of the planting medium will influence ancymidol action when it is applied as soil drench. Thus, the preferred planting medium for pot tulips contains equal parts of soil, peat, and 'Perlite,' or sand. If bark or high peat media are used, be certain the pH is near 7. Otherwise, the ancymidol requirement may need to be increased.

The moisture condition of the planting medium at the time of application of ancymidol is critical. THE MEDIUM MUST BE UNIFORMLY MOIST ! Thus, all pots must be thoroughly watered prior to application of the ancymidol. The most practical procedure to follow is to thoroughly water the pots late in the day and then to apply the ancymidol early the following morning (12 to 24 hrs later).