Controlled Release Fertilizer Application Methods in Plant Nurseries & Greenhouses




Controlled Release Fertilizer (CRF) has made delivering plant nutrition in Nurseries and Greenhouses easier and easier with each new generation of products.


However, the way these products are applied to plants makes a significant impact on their effectiveness. In this post, we’re going to a quick comparison of the three most common ways of applying CRF’s in your Nursery or Greenhouse, Top-dress, Sub-dress, and Incorporation.



Top-dressing

 

Top-dressing is the act of applying fertilizer to the media surface of a containerized plant. This method is simple, and easy to understand, and makes it a great choice for many growers.


Benefits of the Top-Dress Method:

• Easy to understand, just measure the grams according to the label, and evenly distribute on the top of the soil. • You can change the application per plant very easily, making for simple trials and adjustments • You can change the fertilizer, brand, or longevity with each plant to adjust for growth differences. • This also allows for flexibility for small nurseries with very short plant rows.



Drawbacks of the Top-Dress Method:

• Flexibility and adjustment per plant leads to additional labor • Any disturbance of the container could cause spillage and leaking of the prills • Increased chance of weed growth • If drip irrigation is used the top dressed CRF may not receive enough water to push the nutrients into the root zone.



Sub-dressing

 

Sub-dressing, like the name implies, is when you place the CRF just below the surface of the media. This is accomplished by placing the CRF on the surface, then placing a bit more media on top.



Benefits of the Sub-Dressing Method

• Depending on the crop, and media temperature, the application rate can be optimized • Decreased chance of weed growth • Less chance of prill spillage if the container is disturbed • Like Top-Dress, the CRF can be adjusted from plant to plant as the grower requires

Drawbacks of the Sub-Dressing Method

• Additional labor – even more than Top-Dressing as additional soil is now involved.



Incorporation

 

Incorporation is when the CRF is mixed in large batches of media either at a 3rd party blender or on-site before the plants are planted in it.


Benefits of the Incorporation Method

• Efficiencies of Scale, as fertilizer and soil can be purchased in larger quantities, and discounts for volume can be negotiated.

• Reduction in labor, as mixing can be automated or totally outsourced to a 3rd party.

• Highly reduced prill loss if the container falls over.

• Efficiency in operation, no measuring or determining rates with each plant. Just soil, plant and move on.

• CRF Is more efficient within the pre-mixed soil.



Drawbacks Of The Incorporation Method

• All plants using the same incorporation mix receive the same fertilizer, so customization is difficult.

• Efficiencies of scale require a larger nursery operation.

• More planning is required to obtain the highest quality results.


As a nursery owner or manager, the method by which you choose to fertilize with CRF will make a significant difference in its effectiveness and your overall ROI. Don’t go it alone. Reach out to your distributor representative, and manufacturers representative as they can help you plan an effective strategy for your individual situation. No two nurseries or greenhouses are the exact same.