Producing Consumer-Friendly Baskets

Producing Consumer-Friendly Baskets

Plants produced in hanging baskets and large pots have become very important for spring and summer production in many greenhouses. However, consumers and retailers have many challenges keeping containerized plants alive for any length of time. Problems often come down to keeping the plants watered and fertilized.

Growers have come under pressure to improve the lasting quality of their containerized plants. In this six-part series, we will discuss a number of options for making baskets and large containers more consumer friendly. In part one, we will discuss media selection and available water-holding capacity and their effects in keeping plants alive through the summer. The key concept is that containers with high available water-holding capacity require less irrigation by the consumer, but require extra care to avoid overwatering during greenhouse production. 

Understanding Physical Properties

A container root medium is like a sponge. A sponge is made up of holes (called pore spaces) and solids (the medium itself). If you soak the sponge in water and then allow it to drain, the larger holes (called macropores) will have drained and now be filled with air (air space). The smaller holes (called micropores) will have retained the water (water space). The exact ratio between air and water will depend on the height of the sponge (height of the pot), with tall sponges having, on average, more air space and less water space than a shorter sponge.

The maximum volume of water that a root medium can hold after an irrigation (water holding capacity) therefore depends on the physical properties of the root medium, along with the height and volume of the container.

The water held in a root medium can be further broken down into two fractions, available water and unavailable water. Available water is the fraction the plant can extract from the root medium and use for transpiration. Unavailable water is the fraction that is bound so tightly to the medium itself that the plant can not extract it. In general, most of the water contained in a soilless root medium is available to the plant. 

Available Water-Holding Capacity

Available water-holding capacity of the root medium is one of the better predictors in how long a plant in a large pot or basket will go between waterings.

In evaluations of impatiens grown in 10-inch hanging baskets testing different components blended with one type of peat, available water-holding capacity of the blends increased in the order: polystyrene < perlite < vermiculite < rockwool (Figure 1). The 100 percent peat medium had an available water-holding capacity similar that of the peat/vermiculite blend.

After being grown nine weeks in a greenhouse and 11 weeks outside, plants grown in the peat/polystyrene, peat/vermiculite and peat/rockwool blends were similar in size, while the plants grown in the peat/perlite and 100 percent peat media were noticeably smaller. For similar size plants, the average days between watering was 3.5 for the peat/polystyrene, 4.8 for the peat/vermiculite and 6.1 for the peat/rockwool.

Another gauge of a root medium’s ability to supply water to a plant is the minimum days to water, which is a measure of an available water supply during to the plant under hot, dry conditions. This also increased from one day for the peat/polystyrene, two days for the peat/vermiculite and three days for the peat/rockwool.

In a separate experiment testing impatiens grown in 18 commercially prepared root media, the available water-holding capacity ranged from 51 fl. oz. (1.5 liters) to 77 fl. oz. (2.3 liters). Average days between watering ranged from 3.7 to 6.3 days and minimum days between watering ranged from two to four days while being grown outside during the summer.

In this second group of experiments, neither the available water-holding capacity nor the time between watering could be predicted by the components used to produce the root medium. For example, a root medium containing a fine peat with polystyrene had a greater available water-holding capacity compared to a course peat/perlite/rockwool medium.

The difficulty in predicting available water-holding capacity based only on the formulation of the media is that different grades of each component will vary in their water-holding capacity. For example, fine peat tends to hold more water than course peat. Several alternative component/peat blends can end up having identical available water-holding capacities. If you are considering a change in root media and you want to use high available water-holding capacity as criteria, then you need to be able to measure it in your greenhouse to make comparisons (see sidebar).

Test Available Water-Holding Capacity Yourself

All that you need to determine the available water-holding capacity of a root media is a scale and a thoroughly rooted impatiens basket or pot (four to six weeks after planting). Impatiens and New Guinea impatiens work best since the foliage quickly wilts when the available water is gone and the foliage is remarkably tolerant to wilting, so you can test the same pot multiple times.

First, water the basket the way you think it will be watered or with a hose until water starts draining. Wait until drainage stops and weigh the basket. Allow the basket to dry until you observe wilting and weigh the basket again. The difference between the weight after watering and at wilt is the available water-holding capacity. (1,000 gram equals 1 liter; 1 lb. is approximately 16 fl. oz. of water).

Problems With High Available Water-Holding Capacity Media

A reason often used by growers when choosing a root medium for basket or large pot production is “good drainage.” By this they mean small plugs can be directly planted into the basket in January or February, placed on drippers and have low risk of overwatering. Remember, a pot or basket has a fixed volume, so using root media with higher available water-holding capacities can cause some challenges.

With high available water-holding capacity media, there are several management strategies to prevent over watering early in production:

1) Transplanting larger plant material with a more developed root system;

2) Maintaining the baskets on a bench or floor close together for the first few weeks so watering can be more controlled and possibly done by hand;

3) Production in baskets with external saucers that can be left off to provide drainage during production but attached prior to shipping to increase the amount of water retained; and

4) Instructing growers to weigh baskets and not to water until they reach a predetermined weight. These methods may not be practical due to scheduling and labor concerns but should be considered.

Available water-holding capacity is a key criteria for producing consumer-friendly baskets and large pots. Next month, we’ll discuss other ways to extend the time between waterings.

Leave a Reply

More From Media...

April 1, 2015

Philadelphia Flower Show Draws More Than 250,000 Attendees With Disney Pixar Movie Theme

With more than 250,000 consumers attending the prestigious Philadelphia Flower Show in March each year, it's a great opportunity to get flowers and gardening products into the public eye. This year's show displays took on family favorites at the movies, with a focus on Disney and Pixar films. Check out some of the highlights in our slideshow.

Read More

April 1, 2015

Peace Tree Farms Grows Its Customer Base

Over the past five years, Peace Tree Farms in Kintnersville, Pa., has concentrated on growing its business by providing plant material for the displays at the illustrious Philadelphia Flower Show. We caught up with Peace Tree Farms’ Lloyd Traven to ask about how the Flower Show figures into his business plan.

Read More
protecting bees and pollinators video

March 31, 2015

New Video On Protecting Bees And Pollinators Educates Horticulture Industry Professionals

A new educational video that provides information on the horticultural industry’s essential role in bee and pollinator stewardship is one result of industry collaboration by the Horticultural Research Institute, AmericanHort, Society of American Florists and the American Floral Endowment. “Protecting Bees & Pollinators: What Horticulture Needs to Know,” narrates the current state of bee and pollinator health, provides information on factors that impact pollinators and the environment and underscores the beneficial role horticulture plays in providing healthy pollinator ecosystems.

Read More
Latest Stories

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 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

October 27, 2014

Peat Moss May Be In Short Supply This Year

Adverse weather conditions in Canada have played havoc with the peat moss harvest.

Read More

September 24, 2014

Canadian Harvest Of Peat Moss Is Below Average For 2014

The harvest season has been challenging, according to the Canadian Sphagnum Peat Moss Association (CSPMA), with lower-than-expected harvest of peat moss across most production regions in Canada, due primarily to adverse weather conditions across the country.

Read More

July 23, 2014

Liming Requirements And pH Modification For Pine Wood C…

In the last of a four-article series highlighting the production and use of pine wood chips as aggregates in greenhouse substrates, the researchers found growers do not need to adjust their production practices when 20 percent pine wood chips are used as a perlite replacement.

Read More

May 14, 2014

How Pine Wood Chips In Substrates Affect Plant Growth R…

This is the second article of the four article series highlighting the production and use of pine wood chips as aggregates in greenhouse substrates.

Read More

April 3, 2014

The Processing And Properties Of Pine Wood Chips

In the first of a four article series highlighting the use of pine wood chips as alternative aggregates to perlite in greenhouse substrates, researchers from North Carolina State University discuss the processing and physical properties of pine wood chips.

Read More

April 3, 2014

Water And Media Are The Foundations Of Your Business: T…

Electrical conductivity (EC) and pH, as well as water alkalinity, have the biggest effects on nutrient availability. Learn how to keep track of them through three common methods for better monitoring in the greenhouse.

Read More
PlugEase from Acme Group

March 3, 2014

Acme Group Introduces PlugEase, A Line Of Recyclable Ag…

The Acme Group recently announced its new line of recyclable Agrifabrics and plant plug substrate, PlugEase. The products make recycling affordable for greenhouse growers, farmers and horticulturalists.

Read More
Emerald Coast Growers

February 26, 2014

Emerald Coast Growers Constructs New Soil Facility

Emerald Coast Growers has constructed a new, consolidated soil mixing facility to increase efficiency and allow for easier custom blending by crop.

Read More
Combination pH and EC meter. Photo courtesy of Hanna Instruments

February 5, 2014

Test Media pH And EC With The 2:1 Technique, Pour-Throu…

Avoid a buildup of soluble salts and create an environment most conducive to nutrient uptake with these three common media testing methods.

Read More
Fertiss Growing Medium from Oasis Grower Solutions

November 18, 2013

Three New Options For Growing Media

From special blends to mycorrhizae, here are some new options for growth media.

Read More

November 14, 2013

Growing Media: To Mix Or Not To Mix

Thinking about making your own growing mixes to lower costs? There are many things to consider before taking the plunge.

Read More
Berger Logo

November 1, 2013

Berger Acquires Beaver & Lafaille Peat Moss

Berger, a producer of growing mixes, has acquired Beaver Peat Moss & Lafaille Peat Moss, consolidating a long-standing relationship between the companies. The transaction is effective on November 1, 2013. Under the agreement, Serge Lafaille, Beaver & Lafaille Peat Moss’ president, will join Berger’s sales team in order to ensure an easy transition for his current customers. “I am proud to join Berger’s team; we have the same business and growing philosophy, as well as a relentless commitment to being close to our customers in order to offer them what they truly need,” Lafaille says. Berger and Beaver & Lafaille Peat Moss have been partners since 1986. “For Berger, this transaction is a natural evolution of the strong relationship we’ve created with Beaver & Lafaille Peat Moss throughout the past 27 years,” says Berger CEO Claudin Berger. Located in St-Modeste, Quebec, Berger provides growing media and peat moss to professional […]

Read More

August 19, 2013

Students Evaluate Bio Char In Soil

Horticulture students from Olds College in Alberta, Canada, are investigating the viability of using bio char as a soil additive for greenhouse-grown crops. The group includes Emily Stanley, Michael Templeton and Heather Hood. Olds has a very good horticulture program, and I graduated from the greenhouse program there in 1996. Because of my involvement in the program, the group approached me to be a mentor for the study. In this role, I had conference calls with the group every two weeks to discuss the status of the project and offer any insight from a professional grower’s perspective. Bio char is a product derived from a special burning process of organic matter with limited amounts of oxygen. This holds the carbon in the organic matter. When the process is finished, you have a bio char product that can be used as a soil amendment. The students conducted trials on tomatoes and […]

Read More

June 6, 2013

Pro-Mix Is Now On Social Media

Premier Tech Horticulture, which is among the North American leaders of peat moss-based growing media production and distribution, has recently announced the launch of its social media strategy, including the unveiling of its Pro-Mix Facebook, Twitter and YouTube pages for professional and amateur gardeners. Known as a customer-focused and market-driven company, Premier Tech Horticulture strongly believes that today, people are expecting constant interactive communication with brands. As a result, interacting and communicating with external audiences through both new and traditional media remain important elements. Now, with Pro-Mix, this dialogue will also take place online, via new social media platforms that are easy to access for everybody. “These Pro-Mix social media platforms (Twitter, Facebook, LinkedIn, Pinterest, blogs, wikis, YouTube, etc.) present us with unique opportunities to listen to our customers and stakeholders, but also to share with people our 20 years of experience, knowledge and expertise,” says Chantal Duchesneau, marketing and […]

Read More

June 5, 2013

Webinar: Coir Chunk Media – A Good Choice For Lon…

Coir Chunk Media–A Good Choice For Long-Term CropsTuesday, June 11 at 2 p.m. Eastern, 11 a.m. Pacific Click here to register for this webinar. Growing media manufacturers are looking for new components that can be added to their growing media to improve physical properties and address common problems that the grower and/or end user face. One such problem the homeowner experiences with peat-based growing medium in hanging baskets and long term-planters is that they are hard to re-wet with water after they have dried out. Join Horticulture Specialist Troy Buechel on Tuesday, June 11 at 2 p.m. Eastern, 11 a.m. Pacific for this informative webinar to learn how Premier Tech Horticulture is addressing this issue with a new growing medium called PRO-MIX HP-CC. This product contains a unique coir chunk that does not require a wetting agent to wet and helps to hold water while maintaining good air porosity. Find out […]

Read More

April 23, 2013

Premier’s PRO-MIX Marketing Equates Healthy Soil with H…

Professional growers and experienced gardeners have known it for ages: the secret to healthy plants and ultimately, great gardens, begins with excellent soil. Now, that knowledge is being adopted more widely by the average home gardener. To further that knowledge, Premier Tech Horticulture is promoting the idea of creating a $10 hole for a $1 plant using the eight growing mixes in the PRO-MIX line, formulated for a variety of gardening needs. “We’ve developed a variety of soil solutions from organic growing mixes and potting mixes to specialized planting mixes,” says Chantal Duchesneau, marketing and communications director for Premier Tech Horticulture. “Most of the mixes include an all-natural ingredient, MycoActive, a form of mycorrhizae that stimulates a plant’s root system to take up more nutrients and water to improve health and growth.” Two of the PRO-MIX products are: PRO-MIX Ultimate Garden Mix, which is suitable for outdoor plants and vegetables, […]

Read More