Earlier harvests, uniform production push many vegetable crops toward the use of transplants
By Marni Katz
The Grower/ November 2002

Increasing seed costs, marketing advantages and uniform production are driving more vegetable crop growers toward the use of transplants. Since the transplanting boom first struck the western United States in the late 1990s, many crops now are grown exclusively with the use of transplants while others are slowly making the transitions as growers discover potential advantages.

Although transplanting was introduced in California about 30 years ago, it wasn’t until 1999 that a major push was made toward the practice, bringing a huge green house industry to the West that helped supply and support growers making the transition.

In California today, virtually all celery, seedless watermelon, bell peppers and fresh-market tomatoes are grown from transplants, while 90 percent of the cauliflower and an increasing portion of the processing tomatoes, artichokes and strawberries are moving toward transplant propagation. Other crops, such as broccoli, sit on the fence between seeds and transplanting depending primarily on the market conditions.

Seed costs drive choice
A primary factor spurring the adoption of transplant culture is the high cost of hybrid seed, which is increasing every year, says Sandra Fischbein, California division manager for Speedling Inc. in Nipomo, a pioneering nursery in transplant production.

University of California Cooperative Extension farm advisor Richard Smith agrees, noting that most crops that have been widely transitioned to transplanting production have seeds that are either costly, or in the case of celery, difficult to manage.

“With celery, the seed is very, very tiny, it germinates very slowly and it grows slowly," says Smith, who works in Monterey County. “So you’re fighting weeds, compaction, drying out, all those issues with direct seeding. Celery production first went to bare root transplants, and now is almost entirely planted with plugs in trays of 200 to 300 cells.”

Transplanting shortens the season and also provides uniformity, Smith says.

“Instead of tying up the ground for 120 days, you’re just tying it up for 90 days,” he says. “And if you look at these celery fields, they’re king of amazingly uniform.”

In the case of cauliflower, Smith says there is a significant cost increase for planting transplants compared to direct seeding, but that cost is offset in time savings and improved quality. A recent cost study placed the cost of cauliflower transplants at about $130 per acre just for materials compared to seed costs of about $90 per acre.

“Transplanting is more expensive, but you make that back in reduced time the crop is out there, reduced land rates, improved quality and uniformity. That’s worth a lot to the grower,” he says.

Some crops, such as peppers, would simply be cost-prohibitive to direct seed given the high cost of hybrid seeds, whereas broccoli seed is typically less expensive and makes direct seeding the only economically logical choice. Lettuce in the Salinas Valley is often transplanted early and late in the season as growers attempt to push the season to allow them to turn the crop around quickly, though most growers direct seed during the regular season.

Another significant influence on the shift toward transplanting has been rising water costs. Because growers don’t need to worry about pre-irrigation to get seedling emergence, they use significantly less water up front and less overall during the course of producing a crop. In addition, because growers can save two to three weeks in the field, many can cultivate marketing advantages as well by capturing sometimes profitable early season market niches.

“Also, a lot of growers are going to drip irrigation,” Fischbein says. “Drip irrigation, where placement of the plant into moisture is critical, lends itself more toward transplanting.”

Reduced risk
For processing tomato grower Blake Harlan of Harlan and Dumars Inc. in Woodland, Calif., the primary reason he grows virtually all his 2,000 acres of processing tomatoes from transplants is reduced risk. Harlan and Dumars first started transplanting processing tomatoes in 1990 and has quickly converted to 100 percent transplanting from direct seeding.

While he first looked to transplanting to help offset seed costs, Harlan views transplants as a way of minimizing risk during the critical few weeks of emergence.

“On the slimmer margins we’re having to work under, transplanting provides much less risk and takes the guesswork out of establishing a stand of tomatoes,” he says.

“It’s taken a lot of the unpredictability of germinating seed out of the business, questions like, have you got enough or too much moisture, do you need to sprinkler it, break a crust, are you fighting weeds, do you mechanically have to cultivate, use more chemicals or have to handhoe.”

Harlan says his yields and costs are a push between direct-seeded and transplanted tomatoes over the long haul. In fact, in replicated and field studies on transplanting processing tomatoes, UCCE farm advisor Gene Miyao found that the two methods were similar overall in terms of cost and yield, though it will depend largely on a grower’s individual circumstances.

“For the processing tomatoes, my experience has been that whether processing tomatoes are direct seeded or transplanted from greenhouse-grown plugs, the yield and fruit quality are similar,” says Miyao, who works in Yolo County, Calif. “Some experiments are better with one or the other. But I think on the whole the methods of propagation gave very similar results.”

While transplanting has higher initial expenses associated with greenhouse growing and placing the plugs into the field, there are significant savings in seed cost, weeding costs, fewer irrigations, and more likelihood of uniform plant populations and even stands.

Miyao says growers who plant early and late in the season under difficult conditions for stand establishment will benefit the most from transplanting by delaying planting or providing more mature plants to better withstand difficult conditions.

The practice is not for everyone, though, and Miyao cautions growers to make the decision with careful consideration of his or her situation and on small test plots.

Direct seeding proponents
On the west side of Fresno County, processing tomato grower Ted Sheely says transplants are appealing but don’t work into his crop rotation timetable. Sheely likes to have all his processing tomatoes harvested by early July to use water resources during the heat of the summer on other irrigated crops such as cotton, pistachio and garlic. In the Central Valley, Sheely says direct-seeded tomatoes are more conducive to early market production because they seem to withstand frost better than young transplants.

“The only reason we still direct seed is that our direct-seeded tomatoes harvest earlier than the transplanted ones,” Sheely says. “To get those earliest tomatoes, we can direct seed and get earlier tomatoes than we can safely plant transplants. We are able to plant seeds when there is still a threat of frost, because the young cotyledons seem to resist frost better than the older plants.”

In addition, he says, high winds on the Westside sometimes prohibit him from sprinkle irrigating newly planted transplants.

Michelle Le Strange, a UCCE vegetable crops farm advisor in Tulare County, says transplanting processing tomatoes is an effective way to manage parasitic weed infestations, such as dodder, in the field. Because dodder germinated during the time of year when most tomatoes are direct seeded, planting later with transplants helps avoid the window during which the weed emerges. Rapidly growing transplants also provide less risk of early stand loss compared to direct-seeded tomatoes, which can easily succumb to dodder pressures.