Following up on last week’s pre-transplant mum tech tip with your next steps in the process.

PROBLEM: It’s now the second week in June and I want to follow up on LAST WEEK'S TO-DOS (that were for your teams pre-transplant) with some post-transplant tips.

NICK’S TIP: Like I mentioned last week, mums aren’t most challenging crop to produce, but little mistakes early on will set them back and result in reduced quality. Here are some post-transplant BMPs to get your garden mums started strong.

Bring on the fertilizer!

• Get a “soft” water-soluble fertilizer (WSF) like 20-10-20 (or even 20-20-20 for a couple of fertigations) on them immediately after transplant. This process of phosphorus loading coupled with (predominately) ammonium-form N enables liners to develop lateral branches more freely and without the need for growth regulators like ethephon.
• You can also apply a dose of controlled-release fertilizer (CRF) shortly thereafter, once plants are watered in and have adequate headspace at the top of the pot. If you struggle with crown budding each year or plants are not sizing up the way you’d like despite frequent water-soluble fertilizer (WSF) applications, some CRF in your pots can help keep plants bulking up and pushing through crown bud stressors (like cool night temps and fertilizer leaching from soil).

Get a rootzone fungicide on to protect crops during establishment.

• Pythium is generally the disease to look out for in the early part of the mum crop cycle. As temps spike and summer rains start to hit, a hot, persistently wet soil column is just what Pythium needs to strike.
• Fungicides containing etridiazole (FRAC group 14; ex. Banrot, Truban, Terrazole) are generally my suggestion for mums during hotter times of the year. Cyazofamid (FRAC group 21; ex. Segway) is another good option. Wait until roots reach the sidewalls of containers before you apply these as a soil drench.
• Trichoderma-based biofungicides (RootShield Plus and others) can provide excellent disease protection early on, especially if you get it on right away or use growing media with granular forms of these products already mixed in. No need to wait on applying these the way you would with traditional fungicides.
• Mefenoxam (a.k.a. Metalaxyl-M in Canada; ex. Subdue MAXX) is generally not the best option for controlling warm-season Pythium species like P. aphanidermatum due to resistance development among many greenhouse populations.

Have a crown bud management plan in place.

• If the weather pivots and nights get cold, or if it rains for a week straight and all the mineral nutrients flush out of your mums, crown buds will likely start to set. Don’t get caught off guard, start with a game plan.
• Whether you decide to push with feed or break out the ethephon, be prepared for key early warning signs like sudden changes in leaf shape at the developing shoot tips. As soon as you see these little “strap leaves” begin to develop, execute your clean-up plan. Check out more info on crown bud management in another of my tech tips HERE.