Some growers are increasing the number of lines on a standard bed, while others are pushing innovation further, doubling the size of the bed and increasing the number of seed lines along that bed.

“We’ve been growing baby veggies and leaf lettuces for bagged salad mixes on 80-inch beds for quite a while, and now romaine and other head lettuce is going to 80-inch beds as well,” says Franklin Laemmlen, University of California Cooperative Extension farm advisor in Santa Barbara County. “It’s revolutionary because you’re increasing your production by a third on the same piece of ground, which is a dramatic increase.”

Planting technology spurs the trend
Farther north in the Salinas Valley, the practice has been evolving for the past half decade as a means toward more efficient use of resources, including land, water, and fertilizer, according to Monterey County farm advisor Richard Smith. The boon in recent years as been accelerated with the development of specialized equipment to accommodate planting on 80-inch beds.

In fact, the revolution has already taken hold in spinach production in the Salinas Valley, where a significant part of the region’s spinach acreage is now grown on multiple, tightly spaced seed lines along an 80-inch bed.

“You see quite a bit of that now,” Smith says. “In fact, the 80-inch bed culture is taking up a pretty high percentage of the clipped spinach grown for bagging.”

New seeders that precision-plant the spinach seed along 16 to 20 rows on an 80-inch bed have revolutionized spinach production in the Valley, allowing growers to produce consistent quality spinach along the entire bed. Growers plant high rates of seed, up to 1.5 million seeds per acre, but can increase production by 25 percent to 50 percent while using the same amount of land and water.

“You end up planting much more seed per acre, because you are adding an extra 12 to 14 inches of planted area,” Smith says. “You’re probably looking at 25 percent more seed vs. 40-inch beds.”

In addition, growers typically apply about one-third more fertilizer, and must put in additional drip lines between the added rows.

Wider pencils out
But if the increasing acreage on 80-inch beds is any indication, the seed, fertilizer, and other investments pencil out in cost savings associated with using resources more efficiently. Smith says he has seen a significant increase in recent years in acreage of head lettuce, romaine hearts, and other crops grown on 80-inch beds.

Instead of the traditional two lines on a 40-inch bed, lettuce growers are converting to 80-inch beds and placing one or two seed lines along the middle, increasing the total seed lines to five or six.

It’s an especially good fit for bulk lettuce production, where quality and uniformity are less important issues than in fresh-market head lettuce production.

Newer cultivation and seeding equipment specifically designed for 80-inch beds has also helped growers manage the production challenges associated with multiple seed lines. Before equipment innovations, growers typically used modified standard-bed planters to cultivate and seed the crop. As a result, the middle seed lines often were marred by poor drainage and, especially in the case of spinach, poor quality. By allowing growers to better work and prepare the land, newer equipment can improve consistency of production across all rows in the bed.

Since this equipment emerged, many growers in the Salinas Valley have also been experimenting with multiple seed lines along larger beds in head lettuce. Equipment is now emerging that allows growers to handle three wide beds in a pass.

A slow transition into wide beds
Teixeira Farms in Santa Maria is in a second-year experiment growing head lettuce and some cabbage on 76-inch beds. Owner Allan Teixeira, who manages production, says “the jury still hasn’t returned its verdict” on the production system at Teixeira Farms.

“The big problem on the coast is mildew,” Teixeira says. “With high density plantings, you get a lot more mildew. And tip burn becomes an issue because the bed heats up. Right now we are playing with different varieties and just experimenting to see if it will work. Last year was a disaster because we had a lot of tip burn, so we’re working with variety selection on that too.”

The production method has other challenges as well. Weed control is an issue, because hand crews have a harder time hoeing middle seed lines, and growers must learn to manage weeds differently with herbicide applications.

“From what I’ve seen, you don’t want to go into a weedy field with 80-inch beds, because your weeding costs would drive you up the wall,” Laemmlen says.

UCCE recently conducted a weed-control trial comparing various application methods and their effectiveness on 80-inch beds. Herbicide applications on 80-inch beds vary from broadcast to banded applications, so researchers set out to discover which is the most efficient and economical practice. The trial looked at three application methods: broadcast over the top of the bed, 6-inch bands over each seed line, and a combination of broadcasting the middle seed lines and banding the outside seed lines.

The study found that in fields with moderate to high weed pressures, broadcast applications are most cost-effective, whereas banded applications brought the best return in relatively clean fields. In all cases, herbicide selection was as important a consideration as application type.

This type of research is starting to provide support for growers to help them make these high-production systems work in their fields.

“There is a learning curve on this,” Laemmlen says. He adds it appears to be a challenge growers are willing to embrace.