Tips on starting your natural-season garden mum crop

May 17, 2013
Written by Mark Smith
May, 17, 2013 — Garden mums are easy to grow when basic guidelines are followed. Simply plant rooted cuttings and feed. Today’s varieties do all the work when you provide the appropriate feed. Here are some additional tips to get the most out of your crop.

Prior to cutting arrival, make sure the growing area is prepared. Ensure the ground cover is free of weeds and debris to reduce the potential for disease inoculum from the previous season.

This is a great time to check for low spots in your field that may contribute to root rot and other preventable diseases. An easy way to avoid disease, if you do have low spots in your field, is to put your pots on inverted trays to keep them off the ground.


CHECK IRRIGATION AND FERTILIZER SYSTEMS

Irrigation and fertilization checks before the season will help reduce in-season problems. Check that your fertilizer injectors and irrigation system are working properly before you plant the cuttings.

Clean irrigation lines by flushing with chlorinated water containing 2 to 3 ppm chlorine, followed by a 1 ppm chlorine rinse to clear out any debris – you may see some clogging as algae and other debris are dislodged.

Check the drippers after this flush and replace as needed. Zerotol® algaecide/fungicide can also be used to clean and flush irrigation lines. Check the label for instructions on application and use rates. 

You are now ready to get your cuttings planted and growing. Plant your cuttings as soon as they arrive or as soon as they are rooted (if you root your own) to prevent stress that can stall initial growth. Plant just deep enough to cover the root ball, or a bit deeper if using liners grown in Oasis® propagation medium.

Immediately after planting, water-in cuttings with a complete N-P-K fertilizer solution containing full-strength liquid feed. Plant outdoor crops in mid to late June after the night temperatures are above16˚C. By avoiding the cold night temperatures of late May and early June you will actually get more growth and less premature bud initiation.

ADEQUATE POT SPACING

Make sure the pots are adequately spaced to prevent plants from touching and allow the plants to reach their full potential.

For mum production, the growing medium should retain adequate water after irrigation but also drain sufficiently to provide aeration during rainy weather. Ideally, the mix is well drained with 12-18 per cent air-filled pore space and a pH range of 5.8 to 6.2. It is common to use peat-based or heavier bark-based mixes.

Florel® plant growth regulator can be used as insurance against budding. The first application is generally done in propagation, or one to three days after planting at 350 to 500 ppm with a frequency of every 10-14 days; do not apply to stressed cuttings.

The Florel effect is reduced on shoots that have already initiated buds, so it is important to start Florel early in an effort to have uniformly flowering finished plants.

Irrigation with a drip system not only creates a better environment for the plants but also can be designed to significantly reduce water and fertilizer waste. Pulse irrigation can be utilized to more fully irrigate the pot with a drip irrigation system.

OPTIMUM IRRIGATION STRATEGIES

Instead of running one long irrigation cycle, break that irrigation time into two or three shorter segments with off time in-between. This allows the irrigation solution to move laterally in the pot and not just run out the bottom of the pot.

Wilting during the first third of production can compromise finished plant size. However, during the final phases of production, restricting water can be used to tone the plant and prevent excessive growth.

Fertilizer is essential in successful mum production. Lack of fertility during the vegetative development phase (first half of the crop) will adversely affect plant size and quality. It is important to re-feed your pots after rain to get fertilizer back in the media and available for plant use.

Traditional liquid feed programs suggest high levels of nitrogen to start the crop. We have learned through trials, however, that the higher nitrogen levels were not the primary reason for increased growth. The micronutrients and lesser macronutrients that were also increased when the nitrogen level was raised were more responsible for good growth.

Lower N-P-K levels are now possible by supplementing the standard fertilizer with additional micronutrients and magnesium sulfate (Epsom salts). A second injector may be required to avoid precipitate issues in the fertilizer stock tank.

CONTROLLED RELEASE FERTILIZERS

Some growers like to use controlled release fertilizer (CRF) exclusively or as a supplement to liquid feed. If using CRF, be sure to use one containing micronutrients. CRF can be incorporated into the growing medium prior to planting or top dressed after planting.

If at all possible, water-in the plants with a water-soluble fertilizer to boost initial fertility. CRF release is temperature dependent and releases faster during warm weather.

The recommended application rates vary by product and are listed on the labels. High application rates are required to provide adequate nutrition in garden mum production. Regularly monitor medium electrical conductivity (EC); low or decreasing EC values indicate a need for supplemental feeding.

Pinching is no longer required when producing natural season garden mums although in regions with low humidity plants may benefit from one pinch. Many of the newer varieties start branching during propagation, well before you would even think about pinching.

If you still pinch your cuttings, plan to trial no-pinch production recommendations by marking some pots and leaving those cuttings unpinched this year. Record results compared to pinched pots – you’ll likely be pleasantly surprised!

WORKING WITH PGRs

Two plant growth regulators (PGRs) are commonly used for garden mum crops.

• B-Nine® plant growth regulator can be used during the first half of the crop if plants are stretching and becoming soft. Apply as a spray at 1000 to 5000 ppm (2500 ppm is the most common application rate).

B-Nine can delay flowering so avoid applications once you can see buds on plants.

• Bonzi® plant growth regulator is an effective tool to control growth especially in the second half of the crop at drench rates of 0.5 to 2 ppm (which can be applied through drip irrigation systems). These rates will help hold the plant growth without compromising flower timing.

Some diseases that can be found on garden mums are caused by Pythium, Fusarium, Rhizoctonia, Botrytis, and foliar leafspots caused by Alternaria, Septoria, and Pseudomonas cichorii (bacterial leaf spot).

For many growers, these diseases are not a significant issue.

START CLEAN

The first defence for disease prevention is to start clean; use clean cuttings, growing media and equipment. Good cultural practices result in an unsuitable environment for disease organisms.

Easy cultural practices to reduce disease risk are switching from a high ammonium-based fertilizer to a nitrate-based fertilizer once plants are established and growing and maintaining pH at the higher end of the recommendation.

Buildup of salts in the planting media can also contribute to root problems, so regularly monitor the EC and pH to be sure they are within the proper range. Utilizing a sand filter and chlorination system for irrigation if you have a surface water source is also beneficial in reducing disease issues.

Diseases caused by Fusarium sp and Pythium are the most commonly seen diseases in garden mum production.

A preventive fungicide program for Fusarium can be beneficial for producing a healthy garden mum crop, especially in situations where the disease has been a challenge in the past. Palladium® fungicide can be a useful tool in the control of Fusarium.

Heat during summer production and periodic rains can increase the chance for Pythium root rot. A preventive fungicide rotation that includes Subdue MAXX® fungicide can reduce problems that may show up in the crop. For prevention, applications should be made on a 21 – 28 day interval; for active infections apply on a 14-day interval. Rotating different products helps with resistance management. Please refer to the product labels for specific instructions on applications and use rates.

Visit www.syngentaflowersinc.com and look for Cultural Info in the Technical Support drop down menu for more detailed information.

Mark Smith is a technical services representative with Syngenta Flowers. He can be reached at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

©2013 Syngenta. Important: Always read and follow label instructions before buying or using Syngenta products. The instructions contain important conditions of sale, including limitations of warranty and remedy. FLOREL® is registered by Bayer AG. B-Nine® is a registered trademark of Uniroyal Chemical Company, Inc. Oasis® is a registered trademark of Smithers-Oasis Company. Zerotol® is a trademark of Biosafe Systems Company. Bonzi®, Palladium®, Subdue MAXX®, and the Syngenta logo are trademarks of a Syngenta Group Company.

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