A Recipe for White Roots

We made it through another poinsettia season. The 2007 crop was probably one of our most successful from the standpoint of quality and lack of shrink due to root loss.

I read Joe Moore’s article, "Poinsettias and Pythium" in the November issue of GrowerTalks with a great deal of interest. It was comforting to know that other growers were going through the same gut-wrenching worry about root collapse with this crop as I was. Everyone has a different way of tackling a problem, and I just want to add my slant on why this crop turned out so well.

As indicated in a previous column, I'm fairly heavily committed to PlantShield, and it certainly worked well for me in the poinsettia crop. All pot sizes had a hand application of PlantShield at 4 oz./100 gal. of water immediately after planting. My 12- and 10-in. sizes had an application of Banrot at 6 oz./100 gal. of water two weeks after planting, as has been the traditional thing to do. My 10-in. hanging baskets, 9-, 8- and 4.5-in. crops had no Banrot applied to them.

As I'd inherited some rhizoctonia stem rot problems on the bought-in cutting material, in early October I used a mixture of Medallion at 1oz. and Subdue at 0.5 oz./100 gal. in conjunction with a Safari drench at 12 oz./100 gal. on my 12- and 10-in. pots and 10-in. hanging baskets. All the other crops simply had the insecticide drench as whitefly protection, but with this treatment I reapplied PlantShield at the half rate. At a separate time, I applied a half rate of PlantShield to my 12- and 10-in. pots and 10-in. hanging basket crops as well.

Constant monitoring of the root system for soil tests and as an aid in making watering decisions helped build up confidence that the quality of root action was good. I was really impressed with the quality of new white root growth that continued to be produced, especially as the normal stressful late October/November time approached. We have to hold a lot of the crop for church orders, so we need to ensure good quality right to the end. All in all, I had good leaf size and bract expansion. With the current high oil price situation that we all find ourselves in, heating costs for this crop may become cost prohibitive, but if the root system doesn’t hold up, all is lost anyhow. It's encouraging, though, that it's possible to get excited about the quality of the root support system that exists just before the final product goes out the door.

One of our large plants got damaged in shipping, and I decided that it wasn't going to be a total waste. I inspected the root system, gently washed off the compost and was delighted at the internal root mass that existed. PlantShield tends to produce a larger root biomass. Even at that point in time, actively growing new white roots were a joy to see. I found the same results on inspection of other sizes as well.

None of this would have been possible without attention to detail in the initial application of the PlantShield material. For this I wish to thank my "annual two-step dancing partners," as Joe Moore calls them. My retiree grower helpers are Bob, a young 80 years old; Carl, who keeps me in order; and Steve, who had never been involved in growing a poinsettia crop before this year. They all helped in the accurate hand application, cared for the crop along the way and shared with me the joy of lack of shrink as the crop came to maturity.

Throughout the whole process, keeping crop records is so vitally important. Even though it can be a bit tedious at times, it’s important to have an accurate record of everything that was done to the crop. I use a daily log sheet to record all watering and fertilizer applications, chemical treatments and temperatures for each crop. As spring approaches and time gets more precious, it’s important to have a good system in order and to be able to review what was done in the past so we can be even more successful in the coming season. --Roger McGaughey