Bob's Market and Greenhouses in Mason, W.V., has been incorporating a water-absorbing hydrogel into its growing mixes since 1995. When this US company first started adding a hydrogel the growing mixes were produced using stationary concrete mixing drums.

by David Kuack

Scott Barnitz, vice president at Bob's Market and Greenhouses, said his company has been incorporating a water-absorbing hydrogel into its growing mixes since 1995. (Photos by John Morgan, Bob's Market and Greenhouses.)

"We had a rudimentary method of making our soil-less growing mixes," said vice president Scott Barnitz, whose responsibilities include the company's retail operations and its wholesale finished production. "We ran the concrete mixers with hydraulic electric motors. We were able to fully expand the hydrogel and incorporate it into the mixers. We were quickly impressed with the beneficial water-releasing qualities of the hydrogel."

Barnitz said when his company began working with Bouldin & Lawson in 2012 to design and engineer an inline soil system it was imperative that expanded Stockosorb hydrogel could continue to be incorporated into the mixes it was making.

"When we put in the soil system five years ago, we contemplated not putting in the equipment because we weren't sure how it would be able to deliver the Stockosorb," Barnitz said. "Bouldin & Lawson had never done anything like this before. The company designed a hopper that enabled us to incorporate the expanded hydrogel into our growing mixes that we are very pleased with. It has allowed us to continue incorporating the fully expanded gel into the continuous inline mixing."

Stockosorb component of finished plant mixes
Bob's Market and Greenhouses operates over 1 million square feet of greenhouse production and about 5 acres of outdoor production. The company annually produces 150 million plugs and 750,000 finished plants. The plugs, which are primarily annuals and sold exclusively through Ball Seed Co., account for half of the company's revenue. The balance of its sales is finished plants that are sold wholesale and retail.

When Bob's Market and Greenhouses was looking to automate its production of growing mixes, it worked with Bouldin & Lawson to design and engineer an inline soil mixing system that allowed the grower to continue incorporating expanded Stockosorb hydrogel.

"Our wholesale business is basically all independent garden centers and farm markets," Barnitz said. "Our wholesale distribution warehouse in Pittsburgh, Pa., wholesales to garden centers. We also have a retail/wholesale location in Atlanta. We ship our finished product within a 550-mile radius of our Mason location. Atlanta is the farthest that we ship finished product."

Peat is the number one component in the company's growing mixes, followed by perlite.

"We have been using rice hulls for about five years and have also used composted pine bark," Barnitz said.

In addition to the mix components mentioned, the company also adds lime and a nutrient charge. Root Shield, a biological fungicide, is incorporated into the plug mixes along with some of the finished mixes for crops like poinsettias.

"For our finished plants, we use peat and perlite and adjust the amount of rice hulls from zero up to 15 percent," Barnitz said. "The amount of Stockosorb that is added for the finished plants is adjusted based on the size of the container. For our bedding plant flats, which will be transplanted, we won't incorporate as much Stockosorb as we would add for a 10-inch Boston fern or 12-inch or larger deco pot that have a longer production time. For our finished plants, we are putting Stockosorb in just about every mix batch."

Bob's Market and Greenhouses doesn't add Stockosorb to the plugs that it wholesales because of the small volume of the cells.

"We don't incorporate Stockosorb in the plug stage, but we do incorporate it into larger containers from bedding plants flats on up," Barnitz said. "We recommend that growers buying our plugs add Stockosorb when they transplant the plugs into their finished containers."

Stockosorb benefits
Barnitz said the biggest benefit of Stockosorb is less labor needed once the roots get established in the growing medium.

"We don't have to water as frequently," he said. "Therefore, we don't run the risk of overwatering, reducing the risk of root and foliar diseases. The plants run dryer so there is more air in the growing mix so that the root system is stronger.

The amount of Stockosorb added for finished plants is adjusted based on the size of the container. Less Stockosorb is used for bedding plant flats, which will be transplanted, than for longer term crops like 10-inch Boston ferns and larger deco pots.

"We don't have to water as often so we're not overwatering. Until we start getting into the bright, warm conditions of mid-spring, anything we can do to reduce the amount of pressure on the plants is to our advantage."

Barnitz said another benefit of using Stockosorb occurs when plants arrive at their next stop on the way to consumers.

"Whether it's at our wholesale facilities or our retail locations or our independent garden center customers, Stockosorb provides us with a longer time between watering before the plants start flagging or wilting," he said. "Our growers have found that even with the top of the soil looking light, which indicates the soil is drying down, they feel there is less wilting of the plants and less stress on the plants. Every once in a while, we will try growing some plants without Stockosorb and our growers can tell when it is not in a growing mix."

Barnitz said the company's two retail locations have also benefited from Stockosorb.

"At our retail garden centers, we have a leg up during the middle of a hot afternoon with breezy conditions when everything should be winding down moisture-wise," he said. "It's like having a reserve tank of water in the soil. We are seeing the benefits at both our wholesale and retail locations when holding plants."

Even though most of the watering done at Bob's production facility is by automated irrigation, Barnitz said like most growers some manual watering is done to touch up dry spots.

"Consistency is a mark of quality," he said "If we can run the plants on the dry side, irrigation can be delayed until next day which is advantageous. The soil may be dry, but with the roots growing into the hydrogel the plants don't wilt. Having the hydrogel in our soils offers us the advantage of waiting to water."

Stockosorb helps retailers, consumers succeed
Barnitz said Osmocote slow release fertilizer is added to the deco pots and 12-inch hanging baskets.

The number one goal at Bob's Market and Greenhouses is to provide its customers with healthy, actively growing plants, whether it's retailers who are going to sell them or consumers who take them home and plant them into flower beds or set them on a porch or patio.

"That's another advantage to having Stockosorb in the growing mixes because it holds some of the fertilizer that is released," he said. "The fertilizer is dissolving in the soil and some is being absorbed into the hydrogel. It's there as a reserve when the plants are under stress.

"Whether the plants are going to our wholesale customers or being sold direct through our retail to consumers, we strive very diligently to provide them with a plant that is in a very active growing state at that time. Nothing has been over growth regulated, nothing has been starved."

Barnitz said his company's number one goal is to provide its customers with healthy, actively growing plants.

"Whenever retailers take our plants to their stores to sell them, they're going to perform for them," he said. "Or if consumers take the plants home and transplant them into a bed or set them on a porch and start watering them, the plants are only going to get better for the consumers. That has always been our method of growing and Stockosorb helps us achieve our goal."

David Kuack is a freelance technical writer in Fort Worth, Texas.
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