How to Grow Your Best Garden Mum Yet

Dec 01, 2017
By: Annie Beth Donahue
Theme: Growing

Belgian Mums are the perfect fall mum. They are easy to care for and grow well in a variety of container sizes. Belgian Mums also have a great mounding habit and do not require pinching like other industry mums. Left to their natural growth habit, they will be covered with an uncountable number of flowers because they branch better and more often than other mums.

It's important to realize there's a big difference between garden mums and pot mums.

Field of Garden Mums

Pot mums are floral mums typically used in small pots for the desk or as cut flowers, and they can bloom year round. Pot mums will bloom based on their growth time, in a cycle of grow, mature, bloom.

Garden mums, however, are for the fall. Garden mums never bloom until the light is correct. While daylight hours are long, the plant will not bloom. As soon as the daylight is too short, they go back to vegetative growth with no color. This is part of what makes them so desirable. Their time of beauty is limited.

Adding Fall Income

Garden Mum Retail Space
If you are trying to add some fall income to your greenhouse business, growing Belgian mums to expand your selection is a perfect choice. They are not labor intensive, and they won't set you back financially with a lot of up-front costs. These factors make garden mums easy to grow.

You only need to order one mum per standard-sized pot to produce a full, finished container. There are no real heat costs because Belgian mums can grow in full sun, out in a field. The only real expense you will have is planting and irrigation. Pots, soil, and labor are your principal investments. And if you are selling straight from your greenhouse, you eliminate the need for transportation.

The important thing to know is that garden mums are popular, and they should bring a good return on your investment. According to Mick Donahue, co-owner of North Carolina Farms, "It's an easy crop to grow and the gardening public are already looking for them in the fall."

How To Grow The Perfect Mums

Growing the perfect mum is easy. Typically, for the standard 8" size, garden mums are planted one plant per pot, right in the center. To make the planting process more streamlined and accurate, most people will make a jig out two pieces of crossed wood that has a nail sticking out of the middle. The jig will put a dibble in the center of the pot, which can then be replicated over and over in a consistent, cookie-cutter type manner.

Once you've found your pot's center, plant your mum. It can be grown in full sun, even out in an open field. During the generative growth, or flower development period, switch to potassium-rich fertilizers: 15-5-30 or KNO3 at 300ppm until flowers are showing color. Once you see color, use clear water. This will increase the number of blooms as well as vibrancy. Applying magnesium sulfate as a spray before first color will make plants stronger, enhance color and extend shelf life.

Multicolor Garden Mum

How To Order

For our example, let's use a Belgian Mum that has a bloom time of mid-September. Before ordering, you need to know your local market time. Some regions sell more in early September. Other areas have late October and early November buyers. This time frame could vary depending on your zone, or other cultural or environmental attributes.

Even tradition may factor into when the local families in your area start looking for some fall color. (Does your town have a fall festival or craft show where lots of people come to buy decorations?) No matter when it is, you need to know that peak time. Once you choose that date, you can do some calculations that will back you up to your order time.

The first step in making your calculations is knowing what size finished container you want. The most standard size is an 8" mum pan, but you can grow mums in a one-gallon or even a three-gallon container. If you want to grow different sized containers, you will put one plant in an 8" pot and three plants per pot in a three-gallon. Whether you decide to mix colors or do all the same color, it doesn't matter. Raising the ratio of plants to pot based on the increasing diameter will ensure they all look full or finish at the same time.

Once you know your pot size, you will want to give your plants time to grow double the diameter of the pot. For example, an 8" pot will grow a 16" mum. Belgian mums grow, on average, an inch and a half per week. So in 10 to 11 weeks, you'll have a finished product.

Since their bloom time is bred into their genetics, they will bloom in mid-September (or whenever your light is right) whether they are an inch tall or 15 inches tall. The only thing you have to worry about is getting them planted early enough to grow them to the right size before they bloom.

Here's an example:
  1. You calculate your peak garden mum sales time to be in mid-September, around week 38.
  2. Pick varieties that bloom during the desired time. (This page on our website will auto-sort Belgian Mums for you by bloom time.)
  3. You plan to sell the mums in 8" mum pans.
  4. The mums will need to grow out to 16" to make a full, finished product.
  5. Since Belgian mums grow an inch and a half per week, you decide you need 10 to 11 weeks to finish them out.
  6. You count back and realize you want to order your mums to arrive on week 28, or around July 9th.

Tips and Tricks

  • Order early. This gives you an advantage, in that prices typically go up in accordance to the rate of inflation on January 1st, but pre-ordering before the end of the year allows you to get this year's pricing on next year's mums. Because growers are already looking around and considering what is proving to be popular with customers this time of year, pre-orders for Belgian mums opened on November 1st.

  • Order all your mums together to keep freight low. Staggering your crop and extending your window of sales is a good idea, but you don't want to waste money on shipping several orders of mums only a few weeks apart.

  • Plan ahead. If you want to stagger when your products are finished, first figure out your peak, then plan for most pots to be ready by then. You could then have a few smaller pots ready to go early, and a few more prepared to go late. To keep the size of the finished product consistent, you can either grow different pot sizes, change the fertilizer mix to slow down growth, or pinch the later ones back. You could also try planting the later crop in a larger container. There's no right and wrong; you just need to think it through and have a strategy.

  • The information on our website is based on a southern bloom time. If you need information on Northern bloom times, contact us or visit Gediflora's website. This information is important and may affect your peak sales time.

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About the Author

Annie Beth Donahue

Annie Beth Donahue lives in Indian Trail, North Carolina with her husband Brad, and four children. She is a professional writer for both the web and print, and she can be found at

Annie Beth also has a bachelor's degree in music therapy from Queens University of Charlotte, and has either been working with or parenting children with special needs for the past 18 years. She is a children's book author and the founder and president of Signposts Ministries, a 501(c)3 nonprofit that serves families that have children with chronic health problems or disabilities. In her non-working time, she homeschools and oversees the children's care of their small menagerie made up of chickens, two donkeys, a dog, a cat, and a snake.