This year has turned out to be quite different than 2009 for growing and finishing garden mums. Last year it was not only difficult to achieve size, but most varieties also flowered far earlier than expected due to cooler temperatures. The problem for growers this year is stopping growth and getting plants to bud and flower. Below are a few tips to help start the flowering process for your mum crops.
1) Fertilizer – Last year we discussed using fertilizer to push the plants along. Using higher rates and more ammonium helps increase and push vegetative growth over early buds that are already set. Weather patterns this year require an opposite approach:
a. In general, use little to no ammonium or urea in the fertilizer for the last half of the crop. Instead focus on nitrate forms of nitrogen to help prevent both soft and vegetative growth from rising over the buds.
b. Reduce the overall nitrogen rate significantly over the last half of the crop if the plants are growing well and are at the right size for this stage in the crop life cycle. Put the brakes on plant growth and encourage bud set by abruptly reducing the fertilizer rate and by switching from constant feed to a low rate of feed a couple times a week.
2) Water – Especially under warm conditions, a plant never lacking for water will continue to grow. Space the irrigations so the plants just start to wilt, which stresses the plant enough to stop excess growth. In addition, you can reduce soft growth by not irrigating near the end of the day to invoke a mild stress going into the night. Be careful not to overdue the wilt, especially if the salts are high in the pot, as this can cause root damage and foliar burn.
3) Growth Regulators – Growth regulators are an easy tool that most growers use in their regular production system. Bonzi® growth regulators, when used as a drench, have proven to be very useful at the end of the crop. With a Bonzi drench, growth can be stopped with minimal delay in flowering response. Bonzi drench rates from 0.5 to 2 ppm are commonly used. Higher rates may be required this year. If you have used Bonzi drenches in the past, you may need a higher rate or a second application this year.
These recommendations can be the key to fine tuning your crop no matter what the weather brings.