Understanding Plant Nutrition: Stock Plant Nutrition

Understanding Plant Nutrition: Stock Plant Nutrition

Nutrient management for stock plants is similar to other long-term crops. We have worked with several leading stock plant growers both in the United States and overseas over the past decade. Together, we have found the keys for success are fairly straightforward: have an organized plan that includes media and fertilizer selection, organize crops into pH or EC groups, monitor nutrition regularly and ensure adequate levels of all nutrients are present in cuttings harvested from the stock.

1. Start with a quality growing medium. Some growers consistently produce excellent quality cuttings from stock plants grown in gravel, soil or locally produced compost to save costs. However, these locally produced substrates will often present the stock producer with challenges including inconsistent mixing, excess compaction or composting, limited root growth because of lack of aeration or excessive drying, and micronutrient toxicity (often manganese, depending on the rock type) when substrate pH decreases below acceptable levels (Figure 1).

We encourage cutting producers to run media trials using North American or European sphagnum peat-based substrates. In some cases, we have literally seen more than a doubling of cutting yield when several of these growers switched to course sphagnum peat-based substrates from a locally produced substrate.

Often, the plants grown in the sphagnum peat-based substrates have healthier roots and are better able to handle the stress of repeated cutting harvests.

When evaluating substrate costs, remember to include not just the price per pot, but also the value of the additional cuttings produced. We have found that it is easy to justify a higher cost and better quality substrate with even a slight yield increase (Figure 2).

2. Stock plants are long-term crops, so all essential nutrients must be provided on a regular basis. Nutrients must be provided either through (a) your water-soluble or controlled-release fertilizer, (b) growing medium components and preplant charge, © impurities in the irrigation water, (d) acid injection, or (e) periodic supplemental drenches. Typical nutrient solutions used in commercial stock plant production (water soluble fertilizers plus irrigation water impurities plus nutrients from acid fertilizers) are shown in Table 1.

If your nutrient solution has lower concentrations of key nutrients than those shown in Table 1, additional supplemental applications may be needed. In contrast, if a lab test of your irrigation water shows adequate levels of nutrients such as boron, calcium, or magnesium, these nutrients may not be needed from other fertilizer sources.

3. Cutting quality tends to be better when plants are grown with a majority of nitrogen in the nitrate form. Choose a fertilizer that contains at least 75 percent of nitrogen as nitrate. If media-pH tends to rise over time when using high-nitrate fertilizers, consider acid injection of the irrigation water.

4. Organize crops into their pH and electrical conductivity (EC) requirements rather than trying to treat every crop uniquely. Plants differ in (a) their ability to take up iron from the soil solution (iron efficiency) and (b) in their growth rates and root sensitivity to high salt levels. Table 2 shows grouping of a few example crops based on their requirements of both substrate pH and EC.

5. Set up a regular monitoring program that includes:

  • A pre-season complete media and water analysis. Also, check any new batches of growing media when replacing your stock plants during the season.
  • Weekly checks on fertilizer injectors to ensure the desired fertilizer concentration is being delivered.
  • Check water pH and EC at the same time to ensure your irrigation water is not changing.
  • Weekly or biweekly pH and EC testing of growing media. Choose whatever method (1:2, pour-through, SME) works for you, use calibrated meters and a consistent protocol, and select key crops (financially important and prone to problems) rather than trying to test every crop.
  • Test the tissue nutrient levels of cuttings from key crops starting two weeks before harvest. The ideal sample for cutting production is 2 cups (enough for complete analysis including nitrogen) of whole cuttings (so the sample represents the product you will harvest), taken from multiple plants (to be representative), which are washed in distilled water (to remove fertilizer salts) and then air dried (so they will not rot in transit) before sending to the lab.

6. Have an organized plan in which the grower reviews nutrient test results each week, and decides on corrections. Testing without action is not management–it is busy work. Decide what actions will take place when common nutritional problems occur. For example, what do you do when (1) the media-EC is low (we suggest fertilizer drenches with 400 ppm N), (2) media-EC is high (we suggest leach with 50-plus percent of the applied volume), (3) media-pH is low (we suggest switching to high-nitrate fertilizer, stop acid injection, or drench with potassium bicarbonate or flowable lime), or (4) media-pH is high (we suggest injecting acid in irrigation water to a pH of 5.0 and temporarily shifting to a higher-ammoniacal based fertilizers).

7. Have specific actions ready when tissue levels or plant symptoms show a deficiency. There is insufficient space here to discuss correcting all potential problems. However, a few words of caution:

  • If the stock plants are healthy and cuttings are performing well in propagation, do not over-react to lab results. Compare tissue levels against visual root health, media-pH and EC tests, and current fertilizer rates and formulations to come up with a common-sense corrective strategy. For example, deficiency symptoms may have occurred because of root disease rather than lack of fertilizer.
  • Not all “high” or “low” levels in laboratory tissue nutrient reports represent a problem. The deficiency problems we have seen most often in herbaceous cuttings are nitrogen, phosphorus, calcium, magnesium, iron, manganese, and boron deficiencies (Figure 3). Deficiencies in other nutrients are possible but rare. Tissue analyses only represent results at one moment in time on a small sample, and many labs do not have well-established ideal tissue ranges for your specific crop.
  • Ideally, your tissue nutrient levels should be in the upper part of the acceptable range for these nutrients, because tissue nutrient concentration typically declines during propagation while cuttings begin to grow with limited root systems.

8. Some growers add up to 2 ppm iron from iron-DTPA or iron-EDDHA chelate on a constant basis to keep iron-inefficient crops dark green and avoid iron deficiency if media-pH increases above 6.2. This is a good strategy. However, do not supplement high levels of iron to iron-efficient plants or toxicity symptoms are likely if pH drops below 6.0. Do not overdo supplementing any nutrient and maintain media-pH at a moderate level. Otherwise, toxicities (Figure 4) or imbalances can occur.

In conclusion, developing an overall nutrient management strategy for your stock plants will result in fewer problems during propagation of those cuttings.

Leave a Reply

More From Fertilization...
Jim Zablocki, Plant Prod

February 5, 2016

Sign Up For A Webinar On Using Plant Nutrition To Improve Quality

The webinar takes place March 2, and covers how leading growers are using plant nutrition to minimize costs, reduce the number of factors they need to worry about, and lessen environmental impacts.

Read More
Fertilizer Rates Feature Image

January 29, 2016

Bioworks Releases New Higher Nitrogen Fertilizer For Ornamental Crops

Verdanta N-Vita 9-4-3 promotes foliar growth and features a slow release process, making nutrients available for a longer period of time.

Read More
Primrose Downward Leaf Roll From Calcium Deficiency

January 11, 2016

How Calcium Plays A Critical Role In Plant Health

Supply vegetables and poinsettias with a healthy amount of calcium to avoid tip and leaf burn.

Read More
Latest Stories
Jim Zablocki, Plant Prod

February 5, 2016

Sign Up For A Webinar On Using Plant Nutrition To Impro…

The webinar takes place March 2, and covers how leading growers are using plant nutrition to minimize costs, reduce the number of factors they need to worry about, and lessen environmental impacts.

Read More
Fertilizer Rates Feature Image

January 29, 2016

Bioworks Releases New Higher Nitrogen Fertilizer For Or…

Verdanta N-Vita 9-4-3 promotes foliar growth and features a slow release process, making nutrients available for a longer period of time.

Read More
Primrose Downward Leaf Roll From Calcium Deficiency

January 11, 2016

How Calcium Plays A Critical Role In Plant Health

Supply vegetables and poinsettias with a healthy amount of calcium to avoid tip and leaf burn.

Read More
Sustane Research Greenhouse 2015

January 7, 2016

Fertilizer Manufacturers Aim To Deliver Sustainable Sol…

Industry experts discuss the latest trends to help ensure 2016 is your best year yet.

Read More
Fertilizer Rates Feature Image

August 12, 2015

Selecting Fertilizer Rates For Several Spring Bedding P…

Fertilizing bedding plants can be difficult due to the differing needs of the large variety of plants that we grow. Many operations do not grow enough of any one crop to cater the fertilizer specifically for each crop. Therefore, grouping crops with similar fertilizer requirements and having two to three fertilizer strengths available is a practical way to ensure plants are getting the fertilizer they need. With many new plant varieties on the market, we wanted to conduct a trial at Cornell University to determine best fertilizer rates for several common bedding plant crops. 22 Bedding Plants Studied To Establish Fertilizer Rates Plugs and rooted liners of 22 crops (Table 1) were transplanted into 4-inch (500 mL volume) round pots with a commercial peat/perlite based substrate. The plants were grown in a glass greenhouse at Cornell University during the spring season at a spacing of one plant per square foot. Heating set […]

Read More
NSOrganicPlantFood3-1-1_featured

June 13, 2015

UMASS Fertilizer Trials Recommend Nature’s Source Organ…

In a recent online fact-sheet at its Extension website, the UMass Amherst Center for Agriculture, Food and the Environment lists Nature’s Source Organic Plant Food 3-1-1 as “the best liquid organic fertilizer,” according to Dr. Douglas Cox, Stockbridge School of Agriculture. It is called-out by the Extension after a number of years of studying the use of organic fertilizers for growing commercial greenhouse crops. The trials evaluated traditional water soluble and granular slow-release chemical fertilizers. Dr. Cox recommends Nature’s Source Organic Plant Food 3-1-1 as a liquid fertilizer that is readily available, cost effective, OMRI-listed and with good label directions for greenhouses. He also mentions the ease-of-use in how it mixes well with water and can pass fertilizer injectors. “Nature’s Source is currently the best liquid organic fertilizer,” Cox wrote in his article “Organic Fertilizers – Thoughts on Using Liquid Organic Fertilizers for Greenhouse Plants,” “I have seen no foliar chlorosis yet with this fertilizer. Nature’s source is widely available and a great […]

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

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

July 24, 2014

Using Controlled Release Fertilizers To Produce Garden …

Researchers determined whether or not garden mums can be grown with controlled-release fertilizer, and if it reduces fertilizer leaching, as compared with water-soluble fertilizers.

Read More

March 14, 2014

New Foliage Pro Fertilizer Offers Complete Nutrition Pl…

Dyna-Gro Nutrition Solutions has developed a process it says is capable of keeping all 16 essential plant nutrients in solution form.

Read More

January 30, 2014

OASIS Grower Solutions Introduces New One-Bag Hydroponi…

The new 16-4-17 Hydroponic Fertilizer from OASIS Grower Solutions (OGS) is a one-bag solution that replaces two-part systems traditionally used by commercial hydroponic growers. It is specifically formulated for commercial hydroponic production of lettuce, herbs and vegetables.

Read More

December 30, 2013

Fertilizer Changes Growing Mix pH

When considering a fertilizer's influence on media pH, you need to know its acid or basic reaction.

Read More

December 30, 2013

Basics & Beyond: Fundamentals Of Phosphorus Nutriti…

Phosphorus is an essential element, after all.

Read More
Everris Liquid S.T.E.M.

December 30, 2013

New Fertilizers For 2014

New fertilizer products not only deliver optimum nutrition, they also provide for easier application and increased efficiency. Check out these new products to help your operation produce a healthy crop in 2014. Click through on the pages below.

Read More

December 18, 2013

Focus On Fertilizer: Micronutrients And Organics

New fertilizer products are focusing on micronutrients and providing efficient options for organic production.

Read More

August 27, 2013

BioWorks Adds EcoVita To The Verdanta Family Of Biofert…

EcoVita, a homogeneous granular organic fertilizer, has been added to Bioworks Inc.’s Verdanta biofertilizers product family. This fertilizer will be manufactured and supplied to BioWorks by DCM Corporation of Belgium, a producer of natural and organic-based fertilizers in Western Europe. EcoVita is suitable for a wide variety of crops with its gentle release curve including:• Organic fertilization as a base nutrition in potting mixes• Leafy vegetables• Fruiting vegetables (s a top dressing) • Roses and other ornamentals The new fertilizer offers long-lasting and continuous action for 75 to 100 days and contains organic phosphorus (5 percent P2O5) for fast rooting. Nutrients in EcoVita are gradually released by the soil microbes, in addition to producing humus for better rooting and less leaching. EcoVita is OMRI Listed, making it suitable for use in organic production. “We’re pleased to introduce EcoVita 7-5-10 as our organic NPK product to complement our organic products: K-Vita 2-0-20 […]

Read More
[gravityform id="35" title="false" description="false"]