If alcohol-based rooting hormone solutions touch the apical meristem, twisting of leaves (epinasty) can occur. After dipping, keep the cutting vertical (cutting end down) thereby avoiding excess solution running down to the apical meristem (tip). To apply the solution, submerge 0.25 to 0.75 inches of the cutting base into the solution for no more than 1 to 5 seconds. Liquid auxin-based rooting hormone applied as a quick-dip to the basal end of the cutting. Read and follow the label rate for each species. Application rates are species-specific and sometimes cultivar-specific. In general, cuttings are dipped in a water- or alcohol-based solution containing 500 to 1,000 parts per million indole-3-butyric acid, or IBA (Photo 2). Procedures for liquid auxin-based rooting hormones applied as a cutting dip is similar to those indicated for powders. In general, powder forms of rooting hormones are less effective than liquid auxin-based formulations applied at the same concentration. Lightly tap the cutting to remove excess powder prior to insertion into the propagation substrate. The cutting should not be wet as moisture will cause the powder to clump.
When using powder rooting hormones, dip the basal end of the cutting into the talc powder (Photo 1). Hormex Concentrate-0.013% IBA + 0.24% NAA + vitamin B-1įor quick-dips, the basal end of the cutting is dipped into a talc powder or solution containing an auxin-based hormone. Examples of various formulation and ingredients in rooting compounds used for annuals and perennial propagation (powders, liquids, tablets, and water-soluble salts). List of perennial species with low, moderate or high beneficial response from a rooting hormone application in propagation. List of annual bedding plant species with low, moderate or high beneficial response from a rooting hormone application in propagation.ġ Snapdragon 2 Vinca 3 Euphorbia 4 Bandana, maybe others 5 Cultivar dependent 6 Tropical. Application methods most commonly observed among Michigan greenhouse growers is the quick-dips and post stick foliar sprays. Rooting hormones come in various formulations and contain different ingredients (Table 3) and can most often be applied in one of three ways: quick-dips or dipping the basal or cut end of the cutting into the rooting hormone prior to sticking stem base sprays or post stick foliar sprays. Annual and perennial bedding plant species that are listed as having a low benefit typically root without any hormone application. Tables 1 and 2 provide an extensive list of annual and perennial bedding plant species that have a high (difficult-to-root), moderate or low benefit (no hormone) to rooting hormone applications prior to sticking or during propagation.
Rooting compounds are essential for rooting difficult-to-root annual and perennial bedding plant species and sometimes used for those that may be moderately difficult. Of course, when rooting hormones and other cultural practices are combined with optimal environmental conditions, results are high-quality, well rooted liners. Rooting compounds, being liquid or powders, when applied properly aid in rooting of moderate to difficult-to-root species, accelerate root initiation, improve rooting uniformity, increase the number of roots produced and ultimately reduce shrink and rooting time.
Rooting hormones are a great addition to any propagator’s toolkit.