Growth Regulators Growth Regulators and Caladiums – general information: Growth regulators such as B-9 and Bonzi have proven to be useful for various growers around the country. Growth regulators do not eliminate the need for good culture. We believe the best height control for the pot plant trade is achieved by use the proper de-eyeing technique, proper spacing (good light), timely removal from bottom heat and selection of the proper bulb size and variety for the finished pots you are trying to create and use of growth regulators. In most cases, No. 2 bulbs produce smaller leaves and a somewhat shorter plant. Of course too much shade will cause stretching. The following growth regulators have been tried by various growers and research institutes. Serious caladium growers should conduct similar tests: 1) The following growth regulators have been tried by various growers and research institutes. Serious caladium growers should conduct similar tests: 1) Bonzi- Soil Drench. Apply when plants show a few spikes, and are not yet leafed out at the rate of 8 PPM. Remember to wait for the first spikes to show since only a well-developed root structure will take up the Bonzi. The medium needs to be moist, not dry. Pine bark in the mix will reduce the effect of a Bonzi drench and the concentration will need to be increased by about 50%. 2500 ppm B-9 can be added to this to increase petiole thickness. 2) Bonzi-Tuber Soak. Soak tubers for 30 minutes after de-eying in a 8-30 ppm (0.5oz-1oz/gal) Bonzi solution (#3 & #4= 0.25 oz/gal = 8 ppm; #2 & small #1= 0.5 oz/gal = 16 ppm; Large #1, J & M = 1.0 oz/gal = 32 ppm), allow bulbs to dry overnight on the bench and pot them the following day. This will be effective in reducing the height in cultivars like Aaron, Carolyn Whorton and White Christmas and result in an overall more compact sturdier plant for all varieties. As always, when using a drench or a soak, the rate depends entirely on your growing conditions. Growers should experiment to determine the proper rates and exposure for given varieties. 3) Bonzi – Foliage Spray. Some growers have found a Bonzi Spray at a concentration of 1oz/gallon or 30 ppm effective in holding plants. Addition of 2500 ppm B-9 to the Bonzi helps increase petiole thickness and intensifies the colors. 4) B-9 – Foliar Spray. Rate: 1 pound per 40 gallons of water, 2500 PPM as needed; 5-7 days apart, two or three times when leafed out and spaced. B-9 also makes for a very sturdy plant and improves colors. 2500 ppm B-9 applied 7-10 days before shipping improves the product at the retailer/consumer level. 5) Topflor and Piccolo – Recent (2007/08) studies by North Carolina State University have shown soil drenches of 1-2 mg/ 6” pot to be effective at controlling height in caladiums. Growers should seriously consider experimenting with these materials.