With mum season in mid crop, I thought it would be good to do a reprint of recommended fertilizer programs for garden mums.
It is mid season and it’s a good time to revisit your fertilizer program. Mums are heavy feeders during the first few weeks. After flowers are formed, nutrient demand diminishes. Your fertilizer program and fertilizer selection should be based on irrigation water quality, so have your irrigation water tested if it hasn’t been done and conduct regular soil tests to monitor soil fertility.
There are several ways to fertilize mums. Some growers use 100% water soluble fertilizer through a drip system, some use 100% controlled-release fertilizer and some use a combination of water soluble and controlled-release.
1) 100% Water Soluble Fertilizer Using Drip Irrigation
After plants are established using 20-20-20 the first few weeks, switch to 200-250 ppm of 20-10-20 constant feed for 3-4 applications and then rotate to a calcium nitrate based fertilizer such as 15-0-15 for 1 application, then repeat. Once plants start to show color, reduce to 100 ppm constant feed.
2) Combination of Water Soluble Fertilizer and Low Rate of Controlled Release Fertilizer
Use 250 ppm of 20-20-20 at time of planting and constant feed for first two weeks then change to 20-10-20, 300 ppm once per week and use clear water from first color until sale.
Information from the June 5, 2008 edition of the New England Greenhouse Update. http://www.negreenhouseupdate.info/greenhouse_update/index.php