For a new three-part Tech On Demand Podcast miniseries, I turned the golden TOD mic over to Chris Beytes, editor-in-chief of GrowerTalks magazine. Let’s all welcome “Bossman Beytes” to his first-ever podcast! I think he did a heckuva job. Of course, he has decades of experience interviewing people, so it’s not like I was concerned …

In these episodes, Chris asked three poinsettia experts—Gary Vollmer of Selecta One, Rebecca Siemonsma of Express Seed and Steve Rinehart of Rinehart Poinsettias—to share what they think are the BEST poinsettias—regardless of breeder—for a wide range of grower and retailer needs. Combined, they have more than 100 years of poinsettia experience, so they know their stuff!

Chris asks about just about every use—early- to late-season, small to large pots, best core and novelty colors, best varieties for regions from Fairbanks to Miami. He even asks which variety they wish was in their catalog, which variety they wish had never been bred, and which variety is the best poinsettia of all time.

Here’s a breakdown of what each episode in the Best Poinsettia for … series covers:

• PART 1 OF 3: Guest introductions and experience; best early season red varieties; best for autumn; best for big box promos/ad flyers; best for late season; best core red by region; best mini.
• PART 2 OF 3: Best for poinsettia “trees”; best for large containers; best traditional straight-ups; best poinsettias as cut flowers; best for independent garden centers; best florist type; best for fundraisers; poinsettias for the landscape; energy-efficient varieties for cool growing; best for natural, compact finishing; varieties less-prone to whitefly; variety with longest shelf life, sturdiest varieties.
• PART 3 OF 3: Best by color; most unusual novelty; what each guest wishes was in their assortment but is not; what’s an old variety you wish would come back; the most challenging poinsettia requests from growers and retailers; and BEST POINSETTIA OF ALL TIME.

These episodes AND 118 MORE can be found on SPOTIFY, APPLE PODCASTS and just about any other podcast platform you use. Be sure to subscribe so you never miss an episode ... and if you have a minute to leave a positive review, it will be greatly appreciated!

Each week, I’ll work with my buddy Nick Flax, a technical services expert at Ball, to share a concern that’s come up during one of his numerous calls with growers across North America. This week he’s discussing a problem he’s been hearing about a lot lately—powdery mildew.

PROBLEM: We’ve had a lot of ups and downs in the weather this spring, but recent warm-ups across North America have caused humidity to remain high in lots of greenhouses. As such, I’ve gotten tons of calls and emails over the past couple of weeks seeking advice on powdery mildew management.   

NICK’S TIP: This disease is caused by a group of fungal pathogens that result in similar symptoms on different plants—not just one species of pathogen. Several genera of fungi, including Erysiphe, Golovinomyces, Podosphaera and Sphaerotheca, are responsible for causing powdery mildew across the assortment of bedding plants in our greenhouses.  

Among these genera are hundreds of species, most of which are very host specific. This means the powdery mildew spores on your dahlias will not blow across the bench and cause powdery mildew on your calibrachoa.

Powdery mildews are impossible to exclude from your greenhouse. Airborne spore-producing structures (chasmothecia) can travel long distances on air currents from an infected host plant and float into your greenhouse when you open your vents. 

Preventative management is critical. Once powdery mildew establishes a foothold in your greenhouse, it can be challenging to clean up. The other type of spore-producing structure formed by powdery mildews, conidiophores (the white “fuzzies” you often see on infected plants), can create a tremendous number of spores in a short period of time. These spores shed and blow or splash around your greenhouse, resulting in a vicious cycle of reinfection and repeated incidences of disease in your crops. 

Key Powdery Mildew Management Points

Since powdery mildews are ubiquitous and impossible to keep out of your operation, set yourself up for success—especially when you grow powdery mildew-prone crops (ex. dahlias, gerbera daisies, Phlox). 

When possible, grow powdery mildew-resistant varieties, but remember that resistance is not immunity. Resistant varieties are often able to fight off initial infection when disease pressure is low or recover more quickly after infection occurs, but you still need to implement best practices in your greenhouse to prevent major disease outbreaks. 

Manage moisture judiciously in your greenhouse. Powdery mildews thrive under warm air temps and high relative humidity. Water or apply fertilizer early in the day and minimize runoff or leachate accumulation on your floors— especially if you grow over permeable surfaces that will soak up water and not on concrete. 

Vent warm, humid greenhouse air as much as possible. Prioritize dehumidification cycles late in the day to push out excess humidity and vent periodically at night to break up periods of optimal conditions for disease.  

Increase air movement in the greenhouse and through your crops. HAF fans should be on frequently when greenhouse temperatures are warm and humidity is high. Increase spacing between crops (if you have the space) to facilitate better air flow through the canopy and faster dry-down after irrigations/fertigations. 

Apply fungicides preventatively when conditions for disease are optimal. Pay attention to changes in the weather in your area but also think about the humidity load in your greenhouses based on how mature your crops are. The larger/more mature your crops are, the more they transpire (release gaseous water into the air), which increases relative humidity in the crop canopy and in the greenhouse.  

Start with “soft” chemistries to aid in prevention when environmental conditions first become conducive to disease. Potassium bicarbonate-based products (such as Milstop), biofungicides (ex. Cease), insecticidal soaps (like M-Pede), and mineral oil-based pesticides (such as Suffoil-X) can form a protective barrier on the leaf surface that staves off initial infection.  

React quickly when you first notice signs of powdery mildew. This is the time where you may want to break out harder-hitting fungicides to curb a major outbreak before it happens. FRAC group 3 fungicides (including Avelyo, Eagle and Terraguard) are some of the most effective preventatives. FRAC 11+7 products such as Mural, Orkestra and Pageant, and standalone FRAC 11 (strobilurin) fungicides, are good options, as are Pipron (FRAC 5) and Daconil (FRAC M5). 

Rotate, rotate, ROTATE! Because powdery mildews can produce so many spores in a short period of time, repeated exposure to the same fungicides will increase the chances of resistance buildup. If your fungicide applications seem to be ineffective, it’s likely that your local populations of powdery mildew have developed resistance to the active ingredients in your go-to fungicides. If this is the case for you, rotate between at least three of the aforementioned groups of fungicides (for example one FRAC 3, one 11+7, and Daconil) and include a “soft” chemistry in your rotation to cut through resistance. 

Hopefully, you’ve watch all (or at least a bunch) of the VIDEOS your favorite Bobbleheads recorded during California Spring Trials—we’ve gotten a ton of positive feedback (and a few constructive critiques), and I gave you my raw thoughts on the event a couple newsletters ago. Our industry is fueled by new varieties and high-tech crops, and we actually see them released throughout the entire year now at events, field trials and even in the pages of GrowerTalks. But it's best when we can go “live” and capture them on video for you to see in all of their glory.

Editors from GrowerTalks and Green Profit had such an opportunity a few weeks ago at Four Star Greenhouses in Michigan where the new for ’25 Proven Winners assortment was on display. And we recorded three videos to share it all with you.

Get a sneak peek at the newest garden annuals, perennials and Color Choice shrubs from Proven Winners, including a scaevola with a unique flower shape; two genera that are new to the brand (dahlias and begonias); hibiscus; perennial primula; Stokesia; Allium; Salvia; a hosta called Gigantosaurus; blueberries and even an edible rose. There’s so much to see in these three videos!

• 2025 PROVEN WINNERS ANNUALS
• 2025 PROVEN WINNERS PERENNIALS
• 2025 PROVEN WINNERS COLOR CHOICE SHRUBS

AmericanHort is hosting another PLUG & CUTTING CONFERENCE in Orlando this September 23– 25 and it promises to be a top-notch event for all growers producing young plants. As we all know, a great crop starts early in the growing process and this conference is all about setting yourself up for success. It's for propagation specialists as well as growers who propagate from seed or cuttings for their own use.

Orlando offers some awesome opportunities for grower tours, including greenhouses like Costa Farms, Knox Horticulture and Agri-Starts, as well as the high-quality education we all have come to expect from AmericanHort events (of which GrowerTalks is the founding partner—we launched this event with Drs. Dave Koranski and Roger Styer more than 30 years ago!).

The sessions will be led by the most knowledgeable researchers from universities and allied companies, cutting-edge young plant producers and panels of your peers. Expect content covering topics like best management practices, pests & diseases, inputs, crop nutrition and much more.

Mark your calendar to save the dates, click the link above to register, and watch the pages of GrowerTalks magazine in coming months for a three-part series I’m writing that will go into the details behind the conference and dive deep into a couple of topics on the educational agenda.

Questions and comments related to plant growth regulator (PGR) use have been streaming into the Tech On Demand team and on our closed FACEBOOK GROUP recently. We tend to tackle these questions one at a time because of the specific nature of each crop and situation. The peer-to-peer comments in the Greenhouse Tech Team Group are equally specific.

Thankfully, our friends at e-GRO recently published a fantastic alert titled PGRs: WHERE TO START that clearly explains a lot about when and how to use these chemicals to achieve desired results.

In the alert, Heidi Lindberg, Erik Runkle and Roberto Lopez at Michigan State University address PGR use from the perspective of growers trying to develop a plan. The team explains what PGRs are and how they work (the chemistry and affects), and why they’re used (preventing plants form getting too large—for many reasons). Getting to the heart of the matter, the MSU researchers share data on different categories of PGRs and example products in each category.

If you need very specific details down to the product level, be sure to download and save the 2023-2024 PGR GUIDE FOR ANNUAL CROPS and the 2024/2025 PGR GUIDE FOR PERENNIALS.

Did you know Ball Publishing produces TEN e-newsletters, each covering a specific topic or market segment? That’s right, ten opportunities to read timely and relevant news items, research recaps and stories squarely focused on your business interests. And I have to say, the editors have been on fire lately with so much solid information. If you haven’t already, now’s the time to subscribe!

From perennials and tropical plants to cut flowers and controlled environment ag, our experienced editors have the best connections in each market to bring you cutting-edge info. As you read above, PestTalks is written by an Ph.D entomologist—you really can’t get any better than that! Nursery & Landscape Insider is penned by an assistant professor and extension specialist. Acres Online, by the one and only Chris Beytes, is the longest running of the group (20 years!) and covers all of the latest happenings in the professional greenhouse world. On the flip side, buZZ! is the retail newsletter from Ellen Wells tackling everything garden center-related.

I honestly could go on and on about our e-newsletters because each one is a leader in its field and each editor is passionate about the topic they cover in their own unique way. I’m proud to be a member of the group.

CHECK OUT ALL OF OUR NEWSLETTERS, sign up to receive the ones you need and jump back in the archives to read past issues.

Talk to you in a week!