It is hard to believe that the first poinsettias will be shipped to retail stores in just 4–5 weeks and shipments will continue until near December 20. Life becomes hectic in poinsettia greenhouses as the season progresses so it is prudent to establish handling and shipping practices now that will ensure that quality poinsettias are shipped, and quality poinsettias are received.
By Dr. Terril Nell, American Floral Endowment
In the past, growers would ‘harden off’ crops to prepare them for the entire handling, shipping, and handling programs by reducing watering and fertilizer and lowering temperatures. Today, poinsettia performance is best when plants are grown with strong root systems and are grown lean in the final four weeks just as plants were ‘hardened-off in the past. In this ‘How-to” article, I am going to summarize the best management practices into four factors. Let us look at the primary factors leading to successful handling and shipping.
Prevent Bract Edge Burn – This devastating decay of bracts must be prevented because it is nearly impossible to cure once it becomes visible. Bract Edge Burn is caused by calcium deficiency just like tomato blossom end rot. Calcium deficiency causes a small necrotic, black spot on the edge of the bracts. The problem is worse when plants are grown the final 4 weeks with high fertilizer, a generous supply of water, warm temperature, and high humidity. In many cases, it is best to lower the day and night temperatures several degrees during the final four weeks. ‘Luxurious consumption’ of water and fertilizer promotes rapid bract expansion. Calcium is translocated very poorly from the roots to the bracts that result in calcium deficiency and with rapid bract enlargement sufficient calcium is not available in the bracts. The serious problem begins when the burn provides an entry point for Botrytis spores. Botrytis growth is rapid in high humidity once the spores infect the bracts. Entire bracts may be destroyed in 2–3 days. It is best to water plants the day before sleeving and boxing to avoid high moisture levels in the sleeves and shipping boxes.
The solution to preventing bract edge burn: Spraying calcium weekly beginning at the first sign of bract color delivers calcium directly to the bracts and prevents the occurrence of necrotic spots. It is best to use calcium chloride, calcium chelates, or a cal-mag fertilizer. The use of calcium nitrate is discouraged since the plants do not need nitrogen at this stage of growth. Apply calcium at 400 parts per million calcium weekly with a spreader sticker from the beginning of bract color to shipping.
Packaging/Sleeving – It is best to sleeve plants for as short a period as possible. Water plants the day before sleeving and boxing or placement on racks. Moist soil will raise the humidity within the sleeves and promote the growth of Botrytis.
Shipping – Poinsettias need to be shipped at temperatures of 53–57 F. Temps below 50 F will cause chilling damage. If calcium sprays have been used, boxing, storage, and shipping can be 3–4 days. Some varieties may be sensitive to extended storage and shipping periods and the plants may develop yellow leaves and drop leaves and cyathia prematurely.
Provide Display Instructions to Retailers – Share handling instructions with the retailer since some store-level employees may not have handled poinsettias in the past. The key elements for retail handling are:
- Remove plants from boxes and remove sleeves upon arrival. If the plants are on carts, they can remain in sleeves and on carts for a couple of days. Keep carts out of direct sunlight.
- Check soil moisture and water only if the soil is beginning to dry.
- Do not allow water to stand in the pot covers – roots will be damaged if plants sit in water.
- Display in a well-lit area. Avoid direct sunlight and cold air drafts.
- Check soil moisture every 1–2 days and water only if the soil is beginning to dry.
Following these four simple guidelines will make your poinsettias more resilient to the stresses of storage, shipping, and display. And, the plants will perform much better for the consumer.