Photo © merfin | adobe stock

As the coronavirus pandemic continues, Americans are dusting off a term from the past planting victory gardens, driving the demand for vegetable plants up.

The term was coined during World War I by the National War Garden Commission and promoted through propaganda posters advocating that civilians “Sow the seeds of victory” by planting their own vegetables. It returned to prominence in WWII, during which USDA estimates that more than 20 million victory gardens were planted. Fruit and vegetables harvested in these home and community plots was estimated to be 9-10 million tons.

When James H. Burdett wrote the Victory Garden Manual in 1943, the U.S. was more than a year into World War II. Food was scarce. Americans wanted to do something productive and feel self-sufficient.

Burdett founded the National Garden Bureau in 1920 and that organization’s current executive director, Diane Blazek, updated his tome for today’s gardens in a series of blog posts. The first one was about planning, the second one will be about planting, the third one will be care and maintenance and the fourth one will be about harvesting.

Blazek believes customers are looking for a return to normalcy. After posting “Victory Gardens 2.0: 10 steps for planning your own,” she thinks the messaging is a good fit for today’s times.

“Based on the reaction we got, yes, it definitely is striking a chord,” she says. “It’s the one thing you have control over. I can control my garden. I can grow my own produce. I can feed my family. That feeling of empowerment is a big part of it.”

Independent garden centers like Georgia’s Pike Nurseries are using the term in their messaging, as well.

Pike Nurseries has 17 retail locations, 15 in the metropolitan Atlanta, Georgia area and two in the Charlotte, North Carolina area. The company is part of Armstrong Gardens Centers, which is headquartered in California. Although their businesses are allowed to be open in each state, the company decided to close in-store shopping and implement its own online or phone order and delivery or curbside pickup model. Pike’s post-coronavirus marketing includes their own tips for planting modern-day victory gardens.

“Any time the country goes through a difficult time, you see people spending more time at home and watching their pennies a little closer,” Vice President of Marketing Desiree Heimann says. “So it makes sense that you’d start planting your own victory gardens. We started encouraging that and the sales went along with it.”

Not that sales are booming, but Pike has definitely seen a percentage of sales moving toward edibles. Whether it’s veggies, herbs or berries, people are grasping onto that message.

Victory gardens allow quarantined, stir-crazy people to get out in their yard and experience the mental health benefits of gardening.

“We’re being told to isolate and distance, and that’s not what humans do,” she says. “If we can encourage people to go outside and plant their Victory Garden, yes, they’ll have their fruits and veggies that they love to grow, but it’s also a form of therapy. And they can do that safely in their backyard.”

Nancie Corbett, owner of Bluebird Farms, a small IGC in Berlin, Maryland, opened March 23 after a two-month winter break. She’s stayed open for business staffed only with a skeleton crew practicing social distancing. She closed the retail area and has been receiving orders by phone for “porch pickup.”

Corbett has partnered with nearby Windmill Creek Vineyard and Winery on a victory garden project. The winery donated land for 60 garden plots, for which she would sell plants at a 20% discount.

“We’re trying to just keep plants moving and people buying,” she says.

On March 25, the winery hosted a Facebook Live virtual event introducing the victory garden concept. Corbett explained to interested participants how to plan, plant and maintain a victory garden. There were plenty of questions about how to start a garden, what types of plants to use, how to do it organically and more. Now, the winery has a waiting list for the plots. Corbett sees the reason people love the concept.

“It gives people hope,” she says. “They can envision their garden in August and right now each day we’re just trying to get through until the evening when we go to bed.”

The author is managing editor of sister publication Garden Center magazine.

pHOTOS COURTESY OF F&B FARMS AND NURSERY

When COVID-19 hit, F&B Farms and Nursery in Woodburn, Oregon, saw sales drop dramatically within the first two weeks. That’s when the annual and organic vegetable and herb grower decided to slow down annual production and ramp up edible plants. “I decided we’re going to plant every vegetable that we have on site,” says co-owner Leigh Geshwill. “Whatever we’ve got to seed and if we can get more, we’re going to plant them. I kind of figured having seen the first week or two in the grocery stores that food production was going to be top-of-mind for people.”

Even so, Geshwill says the greenhouse couldn’t keep up with demand. “We had people calling us from states we don’t normally ship to looking for product. So it was definitely a crazy year,” she says.

F&B Farms and Nursery is a 90 to 95% wholesale operation, supplying ornamental and edible plants to independent garden centers in Oregon, Washington and Idaho. In 2016, the greenhouse decided to transition all of its edible plants to organic due in large part to customer demand, Geshwill says.

The other issues were space, along with the time and the effort it took to do two sets of production. “I just wanted to be able to run the entire thing organically and have all my space certified and not worry about segregating or how it was treated,” Geshwill says. “I could just have more control over the whole process if it was all organic.”

And the organic trend isn’t one that’s likely to go away soon. Looking at the increase of not just organic produce, but organic products on store shelves, Geshwill sees a lot of opportunity.

“And as we get more savvy on production and growing things organically, that’s just going to continue to grow,” she says. “So I think that if you haven’t made it part of your plan, there’s no time like now. And tie it into health and wellness for people. I think that’s a great plant benefit and it’s a great marketing tool.”

We talked to Geshwill about the demand for organic edibles and where she sees the market heading.

Produce Grower: Do you think this boom in edibles will last after the COVID-19 crisis?

Leigh Geshwill: I think the edibles have been steadily growing anyway, so I think it will continue. And the reason I think that the organic market is a driver, but it’s also just edibles in general. I think consumers want to be more in charge of their health and their nutrition and what they’re eating. That ties into the local food movement. They want to know what it is and where it came from. And so I think growing your own food, I mean, you clearly know where it came from and what happened to it and how it was taken care of. So I think that’s just a continuing trend that people just really feel empowered to be in charge of their own health and wellness.

PG: Outside of the pandemic, what are some other factors driving the organic edible market?

LG: Another thing I think that helps now, especially versus even four or five years ago is just the availability of products. It used to be that you could get some things organic, but it wasn’t a very wide selection. And each year we just see that selection of seed availability and different types of vegetables and herbs really keeps expanding. So that helps sort of drive the sales that you can get. You can get all that variety that people are craving.

PG: What are some of the most popular varieties at the independent garden centers in your area?

LG: I think in a lot of places it’s heirloom tomatoes. In the Northwest, we have a fairly large Hispanic population and also we have some other ethnic groups like Russians that tend to like a lot of the specialty peppers. So, we see that and then of course lettuce, greens and basil and cilantro are the top two herbs. Lots of summer squash, a little bit of eggplant, but generally, we have a fairly sophisticated market. They’ll still buy some Early Girl and Better Boy type tomatoes, but people really want something that’s kind of unique and unusual. So they want it in their plants and they want it in their vegetables.

PG: Is there anything IGCs can provide their customers to help make them successful with an organic edible garden?

LG: Well, I think in our area, most of them do a really, really good job. In general, I think it’s just really educating consumers on the shift in mindset. Growing organically in my mind requires a little bit more planning and thoughtfulness about the whole network. When you grow conventionally, you have a problem and you go solve it with whatever chemical or fertilizer or whatever you need to do. When you do it organically, you have to think about: Have you amended your soil? Do you have a really rich microcosm going on? How are you going to deal with nutrition? Because you’re not going to throw some fertilizer on it. You’ve got to think about how you’re going to maintain nutrition throughout the growing season.

And so I think that it just requires a different kind of mindset or a sort of paradigm shift for how you grow. I think if people haven’t grown organically before that it may just take them maybe a really good seminar. It would help people to sort of plan ahead and then that would make them more successful.

PG: What advice would you give to garden center owners and retailers looking to find a good organic greenhouse partner?

LG: Well, the one thing I would say is there is so much vegetable demand in general. I do notice that some of our IGCs, we’ll do some pre-booking — not their entire sales volume, but maybe 50% of their sales volume. And I think that’s a really good idea just because seed supply is not robust and the availability is not robust. The days of being able to order anything off spec are gone. If you have some need, you need to share that with the grower now. So that if you’re thinking, “My vegetable sales are going to go up 50% next year,” that would be good to tell your grower so we can accommodate that and you’re not struggling looking for product.

That’s mostly what I see is product availability and knowing that you’re going to have something, at least some base level of product to have on your shelf and not be subject to, ‘Oh, I can’t get beans for three weeks.’

One of the many challenges facing tomato (Solanum lycopersicum L.) and kale (Brassica oleracea) greenhouse growers is the management of edema (oedema). Often described as intumescence or enations, edema is an abiotic-induced complication that develops at different levels of intensity depending on the cultivar and, in some cases, between individual plants.

Symptoms

Edema is often described as a blister or callus-like formation that forms predominately on the bottom of leaves. This swelling is the result of the epidermal layer on the leaf expanding due to cellular elongation, which eventually burst as cells reach their limits of expansion

The resulting damage on the bottom-side of the leaf can be characterized by dark brown, tan, or even yellow necrotic tissue on the surface of the leaf that expands past the original location of the blister as a scab-like injury. On the upper side, necrotic spots mark the location of the ruptured intumescence below, while the surrounding tissue is generally chlorotic. Tissue affected by edema is brittle, with the leaf structure cracking under gentle pressure by the fingers. Extensive edema can severely decrease the leaf’s photosynthetic capability and lead to senescence.

Causes

The cause of edema can be linked to a variety of environmental conditions. The long-standing suggested cause of intumescence is the buildup of excess moisture in the root medium paired with conditions favorable to low transpiration (i.e. high humidity).

In a study conducted by Kansas State in 20091, it was concluded that the water content of the root zone may influence the development of edema in tomatoes. Other research has pointed to light quality (lack of ultraviolet light) being a driving force behind the development of edema in Northern greenhouse tomato production.

Due to largely overcast, low light conditions during winter months, most of the lighting provided to tomato crops in greenhouse operations are supplied by high pressure sodium (HPS) fixtures. While these units produce significant amounts of light in the yellow/red spectrum (550 – 650 nm), they lack in short wavelength energy (300 - 400 nm). This shortwave energy is also lost in greenhouses constructed with glass glazing which has relatively low transmissivity of UV light as compared with polyethylene glazing.

In the same study by Kansas State, it was found that UVB helps prevent the formation of intumescence. In another experiment, conducted at the University of Arizona2, using small doses of end-of-day far red (EOD-FR) and a 75% blue light ratio led to a decrease of intumescence injury from 62-70% of leaves being symptomatic to only 5%. Work at Michigan State University3, found dramatically reduced edema symptoms when light with 50:50 Blue:Red ratio was used as compared with 100% Red light.

Edema of kale

In kale, sudden increases in humidity can cause edema, often coinciding with outdoor weather like rain. Edema can be especially impactful on kale crops as the superficial appearance of leaves affects their marketability. Maintaining a low relative humidity within greenhouse environments, and changing management strategies to better cope with outdoor weather will help prevent edema in kale. This may include increasing shading within a greenhouse to reduce use of cooling pads to help manage humidity. Changes to irrigation timing and application or spacing plants further apart may also help to reduce humidity.

Solutions

Controlling the impact of edema should be done on a case-by-case basis for each operation and based on likely causes.

As mentioned before, the severity of intumescence on tomatoes is largely dependent on the susceptibility of the cultivar and individual plants. If the crop is experiencing major leaf senescence and poor yields, it may justify the cost to invest in preventative measures. Most modern lighting fixtures with digital ballasts can run both high pressure sodium and metal halide (MH) bulbs. For older magnetic ballasts, conversion bulbs can be purchased that also allow you to utilize MH bulbs in an HPS fixture. While somewhat less efficient and shorter lived, the benefit of metal halide is it provides more of a “full-spectrum” light output, with significantly shorter wavelength energy. This strategy combining HPS and metal halide could reduce the onset of edema-like symptoms. While a considerably costlier investment, LED fixtures offer the greatest flexibility in light quality. As prices decrease and efficiency increases, LED technology may offer the solution to improved yields through the reduction in intumescence frequency.

For many other growers, the prevalence of edema may not justify the investment of retrofitting an entire greenhouse.

It may also be beneficial to experiment with a variety of cultivars to screen for edema-like symptoms or work with a seed distributor on selecting cultivars that are less sensitive to edema.

No matter the situation, it is advantageous to develop an action threshold to determine at what level of prevalence should you address the issue of edema in your operation.

Editor's note: This article originally ran as an e-GRO alert.

Photo courtesy of Christopher J. Currey

Basil is the most popular culinary herb grown hydroponically or in controlled environments. For greenhouse production, basil is most productive from the late spring to the early fall. During the later fall, winter and early spring, basil productivity decreases and growers are left wishing they had more production to harvest and sell. Let’s explore how to keep sweet basil productive throughout the year.

Temperature

Basil is a warm-growing plant (Fig. 1) During the fall, winter and spring, cooler outside air temperatures combined with less radiant energy from sunlight will lead to cooler temperatures than during the summer. The optimal temperature for basil is around the mid- to upper- 80°s F and shoot growth is greatest at this temperature. Maintaining greenhouses at that warm average temperature is not feasible. However, it demonstrates how basil is clearly more productive in warm temperatures. It is very tempting to grow cooler during the winter, but try to remember warmer air temperatures will lead to greater yields.

Additionally, don’t drop temperatures too cool during the night, either. Basil is sensitive to temperatures below 55° F and while cool night temperatures are also more cost efficient, they can also restrict growth. If multiple zones are available in the greenhouse, basil can be grown warmer in a separate area as opposed to being grouped with leafy crops such as lettuce, spinach, kale and culinary herbs including dill, parsley and cilantro that can be grown at cooler air temperatures.

Light

While basil growth will slow down in cooler temperatures, diminished light will also negatively affect yield. Basil is a high-light crop, with growth maximized at a daily light integral (DLI) of around 29 mol·m–2·d–1. Depending on geographic location, the outdoor DLI will not even be this high in the fall, winter and spring, much less inside the greenhouse where light is often 30% to 50% lower than outside. While cooler temperatures will slow down the rate of crop growth, low light limits yield for basil crops. Minimizing overhead superstructure and equipment, and cleaning glazing materials will help maximize transmission of sunlight inside the greenhouse. But supplemental lighting is the only way to increase the amount of photosynthetic light available to basil.

Targeting basil over other culinary herbs in a greenhouse with any available supplemental lighting will be beneficial. But while nearly all culinary herbs grown in a greenhouse benefit from supplemental lighting in the winter, the relative increase in yields from lighting basil is greater and will make for a better return on investment than other culinary herbs.

Nutrition

One of the natural instincts most commercial growers have is understanding when to boost mineral nutrients to boost plant growth. While that may work for some crops, it is not an effective strategy for hydroponically grown sweet basil. Whether grown at an EC of 0.5 mS/cm or 4.0 mS/cm, there is no discernable effect on plant growth or fresh weight. Basil is efficient with mineral nutrients and, as a result, providing more nutrients will not increase yields. While increasing fertilizer won’t boost growth, be sure to watch for magnesium deficiencies to maintain leaf greenness and marketability.

Planting density

One of the easiest opportunities to boost yields during the cooler, low-light months is by increasing planting density by reducing the space between plants. By increasing the planting density and producing more plants per unit area, yield over your growing space can increase. For instance, if basil is currently on a 6- or 8-inch center, change to a 3- to 4-inch center. There will be an increase in costs for substrate and seed because more seedlings will be grown for transplant. However, this should be more than compensated for by the increased yield and subsequent revenue.

Take-home message

Sweet basil is the most popular culinary herb grown hydroponically. For greenhouse production, the late spring, summer, and early fall can be very productive for basil. However, basil yields in the late fall, winter and early spring can be improved through better management of air temperature, light and plant spacing.

The author is an extension specialist and professor at Iowa State University. ccurrey@iastate.edu