Growing cut flowers in central New Jersey, we have a great climate, an excellent customer base, and fierce competition. New Jersey is second in cut flower farm sales after California. Not only are there dozens of farms nearby our Moonshot Farm in East Windsor focusing on cut flowers, but nearly every vegetable farm and farm stand has sunflowers and zinnias for sale in the summer months. 

As a relatively new farm, we realized that growing flowers in the winter would set us apart from the competition and create a unique niche. Only a few years into growing, we added a heater and second layer of plastic to our high tunnel and dove in head first, growing crops from December through March including anemones, ranunculus, freesia, stock, and tulips.

By all accounts, our first season of winter flower farming was a total disaster. Our greenhouse was overrun with aphids and powdery mildew. We composted many more flowers than we sold. Somehow, we still made a small profit and couldn’t wait to do it all over again. 


winter-flower-farming-learn-from-our-mistakesUsing a farm stand throughout the winter helps us move extra blooms. We run a small space heater in the shed to keep it from freezing. All photos courtesy of the author.


Now, finishing our second season of winter growing, we’ve implemented a ton from lessons learned. Winter flowers are a high risk, high reward crop — with profits tenfold what many vegetables can gross. I hope you can learn from our expensive mistakes and make winter flower growing work for you.


Mistake #1: Relying solely on beneficial insects for pest control

During the main growing season, we have a hefty beneficial insect program to keep pests at bay. Every two weeks, we release minute pirate bugs and predatory mites to deal with thrips, lacewings to control aphids, plus assassin bugs for general pest control. 

In our first season of winter growing, we naively assumed that these predators would work in a heated greenhouse. We even worked with a reputable supplier who helped us plan our insect orders around our greenhouse temps (50° F to 60° F) and spent thousands of dollars buying insects in and paying for insulated shipping. 

We were unpleasantly surprised when the aphids arrived as early as December, quickly followed by thrips in January, much earlier than we typically have them in our unheated high tunnels. We lost our entire crop of freesia, over 3,000 plants, due to gladiolus thrips. And our ranunculus were coated in black bean aphids. Why weren’t the beneficial insects working?

It turns out that the majority of beneficial insects diapause (go dormant) under low light conditions. Even with warm temps up to the 70s, if the days are too short — under 10 hours of light for some species and 12 for others — the beneficial insects won’t eat much and the pests will take over. 

This winter, we opted to scout for pests on a weekly basis and then apply organic pesticides as necessary. We chose a rotation of Azagard, Pyganic, and Mycotrol. Since no native insects are flying during the winter anyway, we felt comfortable with this approach even though we don’t typically use pesticides during the main season. As soon as the days were approaching 10 hours (mid-February for us), when beneficial insects begin to become active, we switched back to biological controls. One beneficial organism we did keep applying even during the short days were Steinernema feltiae (Sf) nematodes, which we spray every two weeks for thrips control. They’re active even during low light conditions and compatible with many organic pesticides. 

With this change in approach, I’m glad to report our freesia are spectacular and thrips-free. And while we still have some hot spots of aphids, their population is greatly reduced.


Mistake #2: Poor airflow

In the winter greenhouse, the two biggest diseases we battle are powdery mildew and botrytis. Cool, wet, low-light conditions are ideal for these fungal diseases to thrive. In year one, we weren’t expecting to battle bad diseases and didn’t proactively manage them. We learned the hard way — when our ranunculus crop was overtaken early on with powdery mildew — that organic sprays work best as a preventive, rather than a reactive measure. 

This year, as soon as our ranunculus sprouted, we opted for a weekly combo of MilStop and Cease which helped a lot. But the game changer for disease management was installing Horizontal Airflow (HAF) fans. As soon as they were up, we started asking ourselves, “Why didn’t we do this sooner?”

We expected the HAF fans to be a large expense requiring an electrician to install, but it turns out they only use 1 amp of electricity each. We were able to install them quickly with some extension cords and zip ties. The difference in airflow was dramatic and immediate, and the fans cost only around $130 each from a local supplier (Beiler’s Greenhouses). Four fans per 34 foot x 96 foot tunnel has made a huge improvement in airflow and disease.

Next year, we’ll be increasing our ranunculus spacing to further increase airflow. While small spring ranunculus thrive at 6-inch spacing, the winter plants get absolutely massive and diseased. We’ll be increasing spacing to 9 to 12 inches for better airflow, while increasing pricing to account for the decrease in quantity.


Mistake #3: Unsold stems

Winter flower farming runs on tight profit margins, and to make it work we’ve found that every single stem has to sell. In year one, our two main outlets were our local farmers market, which drops to bi-weekly in the winter season, and florists. 

For florists, we find winter availability hard to predict. Sometimes it seems like several weeks can pass without a day of sunshine, which essentially pauses bud development until the sun returns. Promising a florist that we would have exactly 30 blush ranunculus felt like a dangerous game, so we were constantly underestimating supply. As a result, we ended up with lots of extra stems and nowhere to sell them on the off weeks of our farmers market.

This year, we added a weekly farmers market as well as a winter flower CSA. Unlike florists, who have very specific needs, our CSA customers get a mix of whatever is in bloom. We operate on a “share the risk and reap the reward” CSA model, meaning that if we have a week with fewer flowers, they will get smaller bouquets. On the flip side, when the sun finally comes out, they get oversized bouquets. 

We now also have a few florists who are happy with grower’s choice buckets, which have been a great alternative to traditional florist sales requiring specific numbers and colors. Finally, we now have a regular weekly farmstand which is a great way to sell any leftover stems. We run a small space heater in the stand on cold mornings to avoid frozen product. With this mix of sales outlets, we’re selling thousands of stems each week all winter and have an empty cooler every Sunday night.


Mistake #4: Growing cheap flowers

Our farm is relatively small, but we have about 4 acres of fields to play with during the summer. During the winter season, we have 7,680 square feet of heated greenhouse space, 4 percent of our total production area. That means we must squeeze money out of every inch of heated space. Yet in year one, we grew lots of what we saw other farmers growing in heated greenhouses, like stock and freesia, without considering return per square foot of limited greenhouse space. 

Figuring out our total profits per square foot per month has been critical in making winter growing work for us. With limited growing space, the speed of a crop is an important factor in its worth; yield is also key. I’ve been surprised to realize that a lot of other factors, such as the cost of propane and the cost of fancy bulbs, are actually less important than I initially thought. How many stems we can grow per square foot per month is the key to profitability for us. This winter we’ve been carefully tracking each harvest to help determine yield per square foot.

In the winter greenhouse, our most profitable crop is tulips, with the net profit (taking into account bulbs, labor, fuel, and other costs) well over $40/square foot. Hyacinths, paperwhites, and other fast-blooming bulb crops are also quick to profit. High-yielding plants like Icelandic poppies, anemones and standard ranunculus are also quite profitable for us. 


winter-flower-farming-learn-from-our-mistakesTulips, ranunculus, and anemones are among our most profitable flowers. We also grow some lower-value blooms like freesia and stock to make for interesting, value-added bouquets.


Conversely, slow, low-yielding crops are the least profitable. Freesia — as much as our customers love it — takes upwards of five to six months to grow and is one of our least profitable crops, netting less than $4 per square foot per month. We have found a good balance in dedicating 85 percent of our winter space to high-profit crops. The other 15 percent can go to lower-profit crops for the purpose of interesting mixed bouquets, where we make up a lot of the loss through the value-add of a bouquet.


Mistake #5: Leaving town before a cold snap

On Christmas Eve of last year, I was sitting on the tarmac on a very delayed flight with two screaming kids and my greenhouse thermometer app alerting me to the fact that the temperature was near freezing and quickly falling. Foolishly, we had kept our plans to visit family even though a record cold snap was predicted.

Thankfully, our farm manager and farmer neighbors came to the rescue, covering the freesia with frost cloth, troubleshooting the heaters, and shoving blankets into any gaps in our greenhouses. But this was a major lesson learned about resiliency.

First, remote monitoring is critical. Govee thermometers work great if you have WiFi in your greenhouses, but MarCELL is another option with cellular signal that doesn’t rely on WiFi. These alarms will wake you in the middle of the night if your heaters are failing. 

Second, avoid having single points of failure. Our greenhouse heaters all rely on electricity to run but automatically connect to a natural gas generator in case of a power outage. I also recommend having two smaller heaters rather than one large heater in each greenhouse. This way, if one fails, you can still keep the crops above freezing. For an emergency back-up, we also have contractor-style propane space heaters. 

Though be very careful using any type of gas heater that vents directly into a greenhouse. Plants are sensitive to the byproducts of fossil fuel combustion, and many growers have saved their crops from freezing temperatures only to find them damaged or dead by the exhaust from direct-vent gas heaters. Permanent greenhouse gas heaters get around this problem by venting to the outdoors.


winter-flower-farming-learn-from-our-mistakesOur greenhouse full of bright blooms on a cold winter’s day. Ranunculus plants can get huge in the greenhouse, so airflow is key.


Finally, we probably won’t ever leave the farm in the winter again. The risk is just too high, and even with the best staff in the world, there is no substitute for being there yourself to troubleshoot a crisis. The good news is we’re finding winter growing to be so profitable that we plan to take summers off starting next year, with lots of time to leave the farm.

Unlike hardy vegetable crops, most flowers in bloom or bud stage will be destroyed by freezing temperatures. Avoid an extreme loss by investing in resiliency from day one.

Ok so, how’s it going? I’m writing this article on March 1, with one month still to go for our second winter season. With improved pest management and airflow, we have thousands more sellable stems. And by adding a CSA, we know that all of those flowers have a customer. Sales are up over 500 percent from last year. We’ve sold more flowers in the first eight weeks of the year than all of last summer. 

While we still get nervous during extremely cold temps, we’ve implemented technologies that help us sleep at night. And we’re looking forward to spending the summer of 2024 somewhere far, far away from the farm. Winter flowers bring plenty of stress, but nothing is quite as magical as the warm, blooming greenhouse on a cold winter’s day. Winter blooms also bring so much brightness to our customers homes and lives during these dark months.


Rebecca Kutzer-Rice owns Moonshot Farm, a specialty cut flower farm in East Windsor, NJ. She grows flowers year-round including in a geothermal greenhouse, for retail markets in and around NYC.