Success With Vegetable Grafting

Grafted Growers began as most successful companies do, which is to say, as a collaboration between innovative, and like-minded individuals. Ricardo Hernandez met his partner, John Jackson, while studying at the University of Arizona Controlled Environment Agriculture Center (CEAC) through a program that paired a master’s student (Jackson) with a PhD student (Hernandez), requiring them to develop a business venture.

Through that program, the pair developed what is now Grafted Growers, a company based in Tucson, AZ, specializing in the indoor production of grafted tomato and vegetable plants for professional and hobby markets. One of the many things that sets Grafted Growers apart from other propagators is the fact that the company conducts 100% of its production indoors using artificial lighting.

grafted growers ricardo 2_web ready

Ricardo Hernandez of Arizona based Grafter Growers. Photo courtesy of Ricardo Hernandez.

Advertisement

When developing their business plan, Hernandez and Jackson strongly believed that this angle would help distinguish Grafted Growers from the competition — and it did. There is currently no other company in North America that does 100% indoor propagation of grafted plants using artificial lighting.

With the success they’ve seen in the American market, Hernandez says he currently hopes to expand the operation to include a facility in Mexico to cater to growers in that region. He is optimistic the technology will be adopted there.

Top Articles
Have a Plan For Climate Change? Why Fruit Growers Need To Act Now

Developing The Product
Hernandez is in charge of research and development and he oversees production. In basic terms, he says the product development process is as follows: “We do the growing, the grafting, and the healing, and then we sell the plant to the growers. From seed to delivery, it takes around 25-28 days, depending on the varieties.”

Hernandez explains that clients will contract with Grafted Growers for a certain number of plants — ranging anywhere between a few thousand to 20,000 — and then give them both the rootstock and the plant seed, which Grafted Growers then propagates for them.

In addition to that product line, Hernandez says the company has another line catering exclusively to the retail market, where they grow for the client using the client’s seed, and propagate plants according to orders.

One of the main benefits that Grafted Growers’ 100% indoor production provides to the client, is that because the plants never see the outside, they’re not exposed to any contamination from viruses, insects, and pathogens. In addition to being sterile, the rootstocks are suited to grow in practically any growing environment.

“We have a way to select the rootstock to be adapted to the region,” Hernandez explains.

“The great thing about [the plants] being grafted is that they come adapted to extreme outside conditions, so they do well anywhere. Depending on the disease and pathogen pressure you have in the soil, you can select a specific rootstock that’s going to do best in that region.”

A Tightly Managed System
When describing the facilities, Hernandez starts by mentioning that the operation uses no solar light, which allows them to give plants the exact amount of light needed, for the right amount of time, at optimal levels.

“This way we can grow the plants faster and we can grow them in very, very high densities because we can adjust the light. In our facility, the light is constant throughout the day and throughout the year. In a greenhouse you have a lot of variation in the mornings or the afternoons. You also have a lot of variation in January and in the summer,” Hernandez says.

Furthermore, the facility is equipped with carbon dioxide (CO2 ) supplementation, which is also tightly controlled. “We manage the CO2 concentration in the room and atmosphere to the right parts per million, so the plants have the optimal CO2. Then we also have a temperature control system, so the plants have optimal temperature,” he says.

The plants are grown vertically on shelves, and when they’re ready, Hernandez moves them to the grafting room where plants are manually grafted. After that, they’re moved into a healing room, where a different set of environmental conditions are present to help the plants heal.

The Many Benefits Of Grafting
Hernandez mentions there’s been a range of studies showing an increase in yield from using grafted plants. He notes that many of these studies have been conducted in greenhouses where the growing environment is already sterile — making the increase in yield that much more significant.

“If you have a substrate-based greenhouse in the U.S., you don’t have disease pressure. There’s been a 20% to 50% increase in yield in the greenhouse reported just because we’re using grafted plants. Now in the field, depending on your disease pressure and your soil, that number would be higher. Some people are seeing between 50% and 100% yield increase,” Hernandez says.

grafted growers ricardo_web ready

Hernandez of Grafter Growers among trays of tomato plants being grown with artificial lighting. Photo courtesy of Ricardo Hernandez.

He says these results come from a combination of grafted plants’ ability to protect themselves against pathogens, and also because the plants’ roots are more vigorous, creating a better pathway between the water and the plant.

This stronger root system helps growers planting tomatoes in arid climates, for example in California, which is currently experiencing its most severe drought on record.

“Basically you have a plant with a stronger root system, so this stronger root system is able to penetrate deeper into the soil. These grafted plants can go deeper into the soil, and also wider, to harvest water that otherwise would be leached to the ground,” Hernandez says.

In addition to the many benefits grafted plants offer to growers, they also provide advantages for seed breeders.

Essentially, grafting allows breeders to focus on a specific set of traits as opposed to whole-plant-based traits. Hernandez explains it thusly: “If you’re a breeder of tomato, you know you can breed a scion that has excellent production, excellent taste, excellent shape, and you don’t have to worry about the properties of the roots.

“Instead, you can focus on one plant to increase the quality of the fruit, and then you can breed another plant and increase the quality of the roots. That will cut down the time on breeding significantly, and then we can just graft those and have a super plant,” Hernandez says.

Although grafted plants offer protection against a variety of pathogens, Hernandez says there are still some that are not protected by grafting. He says a majority of the most common pathogens have resistant rootstocks, and research is being done to develop resistant varieties for additional pathogens.

He cites Phytopthora root rot as an example of a pathogen not covered by grafting, and says growers should be sure to evaluate rootstocks to make sure they cover whatever diseases are a problem in their area before considering using grafted plants.

Reducing Costs
When Hernandez and Jackson started Grafted Growers, one of their primary intentions was to make an affordable product for their client, as they were fully aware of how the higher cost per plant may be a turn off for those not as familiar with grafting’s many benefits.

As for how they’re delivering that promise, a net reduction of inputs, a sustainable use of resources, a reduction in labor, and a reduction in overseeding are just a few of the ways they’ve lowered costs.

“In our system we use about 75% less fertilizer than common or high-tech greenhouses because we recycle everything. We also reuse 98% of our water.”

In addition to recycling irrigation water, Grafted Growers also recycles the water the plants transpire by using an air condenser. That water goes right back into the nutrient solution.

“We’re working with a very sustainable system, and a system that’s very conducive to reducing labor costs, because you basically put the plants inside, and you don’t do anything. Everything is automated —irrigation is automated, light recipes are automated, atmosphere is automated, air movement is automated, temperature is automated — so we reduce the number of people going into that room.”

Even with these reduced costs, Hernandez says that all growers considering grafting should understand they will always pay more for grafted plants, but costs can be saved in other ways.

For example, Hernandez cites a study that shows that if you divide the cost of fumigation per tomato in a conventional field, it costs approximately $2 to fumigate each one. In essence, he says, growers may only be paying pennies for each non-grafted plant, but because they don’t have to fumigate their fields with grafted plants, they can put those costs back into the plant.

The Future Of Grafting
So what does Hernandez see for the future of grafted plants, and for his company?

“I can only speak to what I’ve seen in other countries, but basically just the widespread adoption of it,” he says.

“Growers will have to change their management practices a little bit once they go to grafted plants, but it is a more sustainable way of [producing]. I think eventually it’s going to be the main way of farming in vegetables, especially in other countries where they moved from 10% grafted plants to nearly 80% after methyl bromide was phased out.”

While tomatoes occupy the majority of the market share for grafted plants, other specialty crops including melons, cucumbers, peppers, and even eggplant, are making significant headway.

As for Grafted Growers, Hernandez plans to expand his reach to establish connections with large growers in the Mexican market. He says he’s spoken to several who are interested in partnerships, and has plans to sell them plants from the Tucson facilities, and set up a high-capacity facility in Mexico when the customer base increases.

The future of grafting is bright by Hernandez’ predictions, which means good news for business, and great news for growers.

Robots
Hernandez is moving his business forward—and into the future — with robots. He currently employs manual grafters to graft 15,000 to 20,000 plants a month, but plans on integrating robots into his facilities in the near future to reduce costs and increase precision.

Tomato plants for grafting under artificial lighting. Photo courtesy of Ricardo Hernandez

Tomato plants for grafting under artificial lighting. Photo courtesy of Ricardo Hernandez

“Our system is designed to adopt grafting robots, which are already available in the market. However, in order to adopt them, you have to justify it first with the quantity of plants you’re producing,” Hernandez says.

Hernandez mentions that he will have to expand his operation in order to justify the cost of the technology, but is optimistic for the future.

In order for the robots to work at maximum capacity, he adds that the seedlings that come out of the system must be incredibly uniform so the robots can reduce the amount of waste. However, according to Hernandez, because Grafted Growers produces all of their seedlings indoors using 100% artificial lighting, achieving uniformity is not a problem.

“In a conventional greenhouse it’s very tough to do that, especially in the fall and the winter months due to the change in the environmental conditions. In our system all the plants come with excellent uniformity, so giving them to the robots would be easier. We just have to be at the size where we can justify buying it, but we’re ready for it,” he says.

0