How PGRs Make You Money

A geranium in a 4-inch square pot takes up just over one-tenth of a square foot. Multiplied by four weeks of growing time, it takes up approximately four-tenths square foot weeks in the greenhouse.

How do you know when it is cost-effective to use plant growth regulators (PGRs)? Certainly they can be used to regulate plant growth and size, but that is just one part of the equation.

Chemical costs are the primary concern to growers. There is certainly a variable cost associated with using plant growth regulators. The growth controlled with PGRs allows for tighter plant spacing. Thus, there is less square foot per week cost, and a lower fixed cost assigned to the pot. So, we need to evaluate if the fixed cost savings is greater than the variable cost of the PGR application.

To provide an example, let’s use geraniums grown in a 4-inch square pot. This geranium crop will be grown for 10 weeks. For four weeks, plants will be placed pot tight at 4 inches by 4 inches. For the final six weeks, the plants will be spaced at 6 inches by 6 inches. Let’s calculate the amount of space the crop uses. This is how we evaluate the amount of fixed cost that will be charged to each individual pot. At 4 inches by 4 inches, the plant takes up one-third of a square foot times one-third of a square foot, or 0.1089 square feet. Multiply that by four weeks of growing time and that equals 0.436 square foot weeks. (See Figure 1 in slideshow below.)

At the 6-inch by 6-inch spacing, the plants take up half a square foot by half a square foot, so 0.5 x 0.5 = 0.25 square feet. Multiply that by six weeks of growing time and you have 1.5 square foot weeks. Adding those numbers together gives us 1.936 square foot weeks of growing time used for each individual pot.

Tighter Plant Spacings
So what difference does a PGR application make? We conducted an experiment in which Bonzi at 10 ppm was sprayed onto Medallion dark red geraniums. In this experiment, the resulting plants were 6.4 percent shorter and 16.7 percent smaller in diameter. When it comes to space allocation, we are interested in the change in plant diameter. Smaller-diameter plants can be spaced closer together.

So let’s calculate the improved space efficiency provided by the PGR application. It is impossible to improve the space utilization when the plants are spaced pot tight at 4 inches by 4 inches. Having smaller-sized plants will only affect the space utilized after the plants are spaced at 6 inches by 6 inches. So having 16.7 percent smaller plants means plants will only take up 83.4 percent of the space. We use that number and multiply it by the 1.5 square foot weeks. Thus, with the tighter pot spacing it will only take up 1.687 total square foot weeks to grow the crop.

Cost Comparison
Square foot per week cost normally varies with the size of the greenhouse. Ideally, you should know your own cost. For this example, we will use the cost of $0.15, $0.20 and $0.25 respectively, which are representative of the large-, medium- and small-sized greenhouse.

Without a PGR application, a single pot occupies 1.936 square foot weeks of space. So the total fixed cost assigned to a single pot would be $0.29, $0.378 or $0.489 respectively for a large, medium or small greenhouse. (See Figure 2 in slideshow below.)

With the tighter spacing possible with the PGR application, the fixed cost per pot is lower, at $0.253, $0.337 or $0.422 respectively for the large-, medium- and small-sized greenhouse.

The difference is the savings offered by the tighter pot spacing when using a PGR. It equals 3.7 cents, 4.8 cents or 6.2 cents per pot respectively for the different-sized greenhouses.

Now, we calculate the cost of applying the PGR. When one calculates the chemical costs of spraying 10 ppm of Bonzi based on $100 per quart, the cost to treat 9,000 pots would be less than $5. The cost to treat an individual pot would be less than one-tenth of a cent. In this example, labor costs were not included since the time it takes to apply a foliar spray would be small.

The savings add up. Savings provided by the increased space efficiency would be $37, $48 or $62 per 1,000 pots respectively for a large-, medium- or small-sized greenhouse.

In summary, there are economic benefits besides controlling excessive stretch when it comes to PGRs. PGRs allow for tighter pot spacing, which then translates into an increased profit per pot. Costs savings make the use of PGRs a key component when it comes to best managing practices for floriculture crops.

 

Leave a Reply

More From Crop Inputs...
Gaillardia x grandiflora 'Arizona Apricot'

February 25, 2015

National Garden Bureau Designates 2015 As Year Of The Gaillardia

Gaillardia, also known as the blanket flower, is a member of the sunflower family (Asteraceae) and a long-blooming pollinator plant. It is fitting that the National Garden Bureau has specified 2015 as The Year of the Gaillardia.

Read More
IPPS Sharing Plant Production Knowledge Globally Logo

February 25, 2015

International Plant Propagators Western Region Sets Annual Meeting Date

The annual meet for the International Plant Propagators' Society (IPPS) Western Region has been set for this September. It will take place September 23 to 26 in Modesto, Calif., and will include learning sessions, tours to local nurseries, a research poster display and poster presentations, various networking opportunities and an awards banquet to close the event.

Read More
Evolvulus Blue My Mind

February 24, 2015

Blue Ribbon Bloomers For Greenhouse Production

Grow what consumers want! Surveys show that blue is one of the top preferred colors of today’s consumers. Here are twelve top recommended blue-flowering Proven Winners annuals and perennials to suit your spring production cycle.

Read More
Latest Stories

February 17, 2015

A New Look At Biological Control: Can Plants Affect The…

The success of a biological control program depends on a number of factors including quality of natural enemies, timing of release, release rates and environmental conditions. However, what is typically not taken into consideration is how plants can affect the performance of natural enemies, including attack rate and searching ability. Biological control agents work hard to protect plants, but plants have ways to help themselves, too.

Read More

February 1, 2015

New Pest Control Products For Your Toolbox

Add one of these new insecticides to your IPM program for successful pest control.

Read More
IR-4_profile_Feb2015

January 29, 2015

IR-4: A Pest Management Resource For Growers

Almost 40 years ago, IR-4 (Interregional Research Project Number 4) began serving the ornamental horticulture industry, helping to facilitate the registration of pest management tools. IR-4 does this primarily by surveying growers about their pest management issues and then hosting workshops to review survey results and set priorities for the coming years. Most recently, IR-4 coordinated a meeting of researchers and industry members on pollinator health and neonicotinoid chemistries to start a discussion on the needed research. The next step will be to get the outcomes from that workshop out to the public.

Read More

January 28, 2015

Biocontrols 2015 Conference & Tradeshow: Peace Tree…

Lloyd Traven, a speaker at the upcoming Biocontrols 2015 Conference & Tradeshow, was one of the industry’s early adopters of biocontrols in the greenhouse. Traven, owner of Peace Tree Farm, is evangelical about the technology as an effective tool for resistance management, as well as improved plant quality that contributes to a grower’s bottom line.

Read More

January 27, 2015

Southwest Perennials Improves Production, Shortens Crop…

A father-and-son team find LEDs deliver a higher rooting rate for cuttings propagated under the lights.

Read More
Wainwright-web-620x349

January 22, 2015

Quality Control With Biocontrols

Make sure the shipment of beneficials that just arrived is viable and ready to go to work in your greenhouse, nursery, or field. Here are five steps you can take to ensure success with your biocontrols.

Read More

January 9, 2015

6 New Fertilizer Products For Healthy Plants

These five products add even more options for delivering nutrients to the root zone.

Read More

January 7, 2015

Fertilizers And The Future

As growers look for new ways to cut costs and conserve resources, fertilizer and equipment companies are offering products that strive to save water, reduce toxic runoff and keep chemicals out of the equation.

Read More

December 31, 2014

Gain Greater Control Of Fertilizer With Automated Ferti…

University researchers look at integrating irrigation and fertilization with the help of water sensors to reduce fertilizer treatments and improve application timing.

Read More
As directed by EPA, the bee hazard icon appears in the Directions For Use for each application site for specific use restrictions and instructions to protect bee and other pollinators.

December 9, 2014

Fact Sheet: The Value Of Neonicotinoids To Turf And Orn…

An extensive study of the diverse turf and ornamental industry (“The Green Industry”) reveals that neonicotinoids are the top-rated products used by professionals to control their most important pests in greenhouses, landscapes, lawns, nurseries and trees.

Read More
As directed by EPA, the bee hazard icon appears in the Directions For Use for each application site for specific use restrictions and instructions to protect bee and other pollinators.

December 9, 2014

New Study Finds Neonicotinoids Are Top-Rated Products F…

According to results of a survey by AgInfomatics, professionals in the turf and ornamental industries fear the loss of neonicotinoid products would reduce the quality of their plants and services, increase costs and negatively impact their ability to manage pest resistance.

Read More

December 2, 2014

Grow-Tech Announces BioStrate, Its Newest Hydroponic Gr…

Grow-Tech LLC recently announced the release of BioStrate Felt, a biobased textile specifically engineered for the growing of hydroponic microgreens and baby salad greens.

Read More

November 25, 2014

Former Harris Seeds Co. CEO, Per Jensen, Passes At 85

A passion for plants defined long-time industry influencer.

Read More

November 21, 2014

Ramped-Up Predatory Mite Production To Benefit Growers

Biological pest control company Beneficial Insectary is now producing both Amblyseius (=Neoseiulus) cucumeris and Stratiolaelaps scimitus (formerly Hypoaspis miles) at its facility in California. Domestic production in the U.S. is now benefiting growers in North America by reducing the transit time of perishable predatory mites between producer and grower.

Read More

November 18, 2014

7 New Media And Light Products For Greenhouse Productio…

New media and light products cover a broad sweep of growing conditions.

Read More

November 14, 2014

Skagit Gardens To Eliminate Use Of Neonicotinoid Pestic…

Skagit Gardens, a wholesale grower located outside Mount Vernon, Wash., will eliminate all use of neonicotinoid pesticides beginning in January 2015.

Read More

November 11, 2014

Clarification: White House Recommends Sourcing Insectic…

UPDATE: The Obama Administration's addendum to the Sustainable Practices for Designed Landscapes applies only to federal agencies “implementing landscaping practices on agency-owned or leased land or space.”

Read More

October 30, 2014

Basics & Beyond: Comparing Substrate Fertilizer Ame…

Cornell University researcher determines if substrate-incorporated slow-release fertilizers can be used to replace or reduce the need for liquid fertilizer for four spring crops.

Read More