Feb 17, 2021
How to work with an organic greenhouse for the best transplants
Stephen Kloosterman

Organic growers can get a jump on the season with the transplants, but organic standards must be upheld.

That means either growing your own transplants, or contracting with a greenhouse to grow them organically.

“The warm-season crops – watermelon, cantaloupe, tomatoes, peppers and eggplant – you want a jump on the season because our season (in the upper Midwest) is so short here that you want to hurry up and get that crop mature so that you can get full production out of it,” said Michigan State University (MSU) Extension Educator Ron Goldy.

“Now, for the cool-season crops – cabbage, broccoli, cauliflower and that group – you just get a better plant stand. You can direct seed them, but you don’t get as good a plant stand and, plus, for that spring planting, you want to get it out before it gets too hot. Those crops, you want to get them harvested by late June at the latest and then you can go ahead and put in other transplants for a fall harvest,” he added.

Why consider a greenhouse? 

Jeff Mast
Jeff Mast is general manager for North Carolina’s Banner Greenhouses in Nebo, North Carolina which grows certified organic vegetable transplants for growers. Photos: Banner Greenhouses

“Mostly all organic vegetable farmers rely on transplants, and so many commercial transplants are not from organic seed or not the variety the organic grower is seeking, so they often resort to growing their own,” said University’s Vicki Morrone, an Organic Farming Specialist at MSU’s Center for Regional Food Systems.

It’s a decision that many growers face.

“Our biggest competitors are our customers, who may not value their time, or feel philosophically that they have to control the process from seed to produce sale,” said Jeff Mast, general manager for North Carolina’s Banner Greenhouses, which grows certified-organic vegetable transplants for everyone from gardeners to large-scale commercial growers. “It might be a lifestyle (decision), it might be philosophical. It might not necessarily be a business decision. We feel what we offer is a specially-grown plug that not all growers have the ability to grow because they may not have the ability, or they may not have the equipment.”

Goldy said there are many business advantages to using a commercial greenhouse for growing transplants.

pullquote“The facility that you’re contracting with has everything it takes; has the heated greenhouse, has the light that it takes,” he said. “A lot of the smaller producers don’t have good enough conditions to grow out a really nice transplant – and some of them don’t have the knowledge either. Smaller producers, the biggest single problem they have is over-watering, leading to damping off.”

While seed-saving and seed-sharing are popular among many organic growers, Goldy said it leads to other challenges.

“Any disease that was on that plant when they took that seed has a high probability of being transferred to the next generation,” he said. While there are ways of sterilizing the seed by one’s self, “I hesitate to give anybody a recipe, because the chances of it going bad are pretty good.”

The costs associated with growing transplants are also in having the staff to check on plants two times per day, Mast added. And there are, of course, economies of scale for a greenhouse operation that serves many growers.

“We might be growing kale for 50 customers at one time, and each one benefits from the economy of scale on our side,” he said.

Getting a grip on grafting

Banner Greenhouses also offers tomato plants grafted to vigorous rootstocks for better disease resistance and yields.

“It started out primarily for heirloom varieties because it did reduce disease pressure,” Mast said. Other growers have asked for it with hybrid tomato varieties since then, but the heirloom variety Cherokee Purple is still the No. 1 most-requested grafted plant.

“Everybody’s needs are different,” he said. For some, it’s more production for higher yields, while other growers are concerned with disease resistance or nematodes.

Mast said he bought a foreign-made robotic grafting machine about 5 years ago but eventually returned to hand-grafting.

“We found that (with) the hand grafting we had a higher success rate, and the rate per hour was about the same by hand as it was by machine,” he said, because of the delicate construction of the machine.

“You just can’t replace the human eye, not yet anyway.”

How to approach

Ron Goldy
Ron Goldy

While it’s possible to grow your own, the expertise and setup of a commercial greenhouse can be effective.

Goldy said it’s important to talk to growers well in advance and to get commitments in writing.

“If you don’t have a contract, then you may not have the greenhouse space,” he said. “You don’t do it the day before you want the seeds in the greenhouse – unless you’re only growing a few hundred plants, then there’s probably space. But for some of these larger things, you’re putting 10,000 plants to the acre, so that’s a lot of plants for greenhouse space, so you want to have that relationship well ahead of time.”

Banner Greenhouses seeds a small number of transplants anticipating last-minute demands from growers, but Mast stressed that it’s a very limited number.

“We prefer customers do order ahead of time so we can grow what they want, and get it ready when they want it,” he said. “We do grow a small quantity on what we call spec, on speculation, because there are always growers, farmers who have problems with their transplants, they forget to order or they see an opportunity.”

Banner greenhouses
In addition to spring vegetable transplants, Banner Greenhouses also grows strawberry plants for the fall.

In ordering transplants or drawing up a contract, a plant date is the first detail to establish, so the greenhouse grower can start planning.

“They just look at the planting date first, the date that the grower wants it in the ground, and then they’ll back up from there, knowing the time that it takes to get the transplant to the right size, and that varies with the crop you’re working with,” Goldy said.

Another detail to think about while setting up an agreement is how the seed will be procured. Goldy said in many grower-greenhouse relationships, the grower would supply the seed to the greenhouse. But Banner Greenhouses also has a standard operating procedure for procuring seed in its transplants.

“We have to search for certified organic seed and then we have to have a record of that search for organic seed,” Mast said.

Inside an organic transplants greenhouse

Greenhouse transplants lined up at Banner Greenhouses.

Banner Greenhouses, located in Nebo, North Carolina, is a 19-acre operation whose main focus is on annual ornamentals and flowers.

“At one point we were looking to diversify our products and we started now doing some greenhouse production of tomatoes and colored bell peppers,” Mast said.

The small area developed for tomatoes and peppers was already certified organic when the group discovered a niche for selling organic vegetable transplants.

“Talking to organic growers, it seemed like there was a need in the marketplace, there,” Mast said.

Today, the Banner Greenhouses have about 5.5 acres of outdoor growing fields for conventional flowers, in addition to 6 acres of plastic greenhouses and 6 acres of gutter-connected greenhouses, and a 1.25-acre high tunnel. About 1.5 acres are certified for organic growing. While organic transplants have remained a niche of the organization compared to its business in ornamentals, the vegetable transplants business has been successful in that slot. One part-time employee handled organic transplants when they started; now six full-time employees are involved, Mast said.

The greenhouses’ organic production uses a different source of water than the conventional growing systems and some machinery is either kept separate between conventional and organic – all other machinery is cleaned and disinfected.

The organic operation includes the use of new plastics, new soil and no compost, Mast said. The soil has different nutritional blends depending on the genus of the plant, and the nutritional health of plants measured by tissue and soil samples sent to a lab during growing.

“The goal is to minimize or eliminate compromises,” Mast said. “We’re professional growers. We grow vegetable transplants year-round, and we’ve been able to really dial in this system that works for us.”

Organic transplant customers buy anything from a few plug trays to a semi loads “and anything in between,” Mast said. “The bulk of our customers are probably market farmers. They’re growing a mix of vegetables they’re selling in farmers’ markets.

“We’re helping to make organic produce accessible to more consumers, we hope,” he said.


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