Let’s discuss granular fertilizers! Why even use a granular? And what are some of the ways you can use them in landscape plantings and in potted plant culture? There are a number of advantages to applying a granular fertilizer, including:

• No mixing
• Slow release
• Season long fertility

No Mixing

Unlike liquid fertilizers, you don’t have to trouble yourself with dilutions. Though these aren’t particularly onerous, what you mix up in a solution is what you need to apply. In contrast, when using a granular fertilizer, you apply a measured dose per tree, bed, or pot. Easy!

Slow Release

Another key advantage of using a granular fertilizer is that they are designed to supply a slow release of nutrients. Implicit in this is that you are less likely to burn a plant or cause fertilizer run-off. Both good things!

Season-Long Fertility

The slow release of a granular fertilizer means less work. Depending on the application, you can get season-long activity or, with a split application, apply only twice a year: spring and fall.

What to Look for in a Granular Fertilizer

Deciding what to apply depends on two basic factors: what the soil is like, and what plants you are growing. Your soil will have certain physical, chemical and biological attributes. Soils can have a low pH (acidic), generally coastal soils, or a high pH (alkaline), generally mid-western soils. Acidic soils tend to have metal ion availability (iron, manganese, zinc, copper, etc), whereas alkaline soils tend to have base minerals in abundance (calcium, magnesium, sodium, etc).

My advice it to test your soil for both pH and mineral availability. Species of plants have adapted to either condition: match what you grow to your soil conditions and you will experience greater success and ease of gardening! The stage of plant growth is an important factor to consider when applying a fertilizer. Care needs to be taken with newly planted trees, shrubs, vines, perennials and annuals. The process of planting (transplanting) incurs root loss. This is commonly referred to as transplant shock. Allow a minimum of two to four weeks post-planting to make your applications. This is where a granular slow-release fertilizer can be advantageous, since it allows you to apply the product at time of planting.

An example of a granular fertilizer that can be used in new plantings is NutriRoot Granular. It has an analysis of 3-3-3, which is the nitrogen, phosphorous, and potassium amounts supplied in pounds per hundred, respectively.  Additionally, it has some unique components that enhance the microbial activity in soils including seaweed extract and a humic component (leonardite).

Next let’s look at two practical applications in gardening.

Granular Gardening: Tree Fertilization

Chinese date (Ziziphus jujuba) or Jujube is an exotic fruit bearing tree. It belongs to the buckthorn family and grows well in temperate and tropical climates. I planted one two years ago, bare root, so it is now well established. The first task: remove weeds growing under the tree. Based on tree size (~1” caliper), I applied according to label, ¼ cup of NutriRoot Granular. Once applied around the base of the tree, rake in or apply a mulch to cover over. Incorporating or covering over the granular is an important step: it reduces volatization of nitrogen to the atmosphere and prevents wildlife like birds from ingesting the granules.

Here is what the process looks like:

Granular Gardening: Pot Culture

Bay Laurel (Laurus nobilis) is a member of the laurel family and native to the Mediterranean region. We can grow it here as a potted herb plant. It is the source of bay leaf, a seasoning used in cooking. I prefer to make up my own soil blends for potted plants. I used Happy Frog soil conditioner and blended in perlite. The ratio by volume I used was 7: 3, respectively. I bulked the bottom of the pot with composted woodchips and to it added a sprinkling (1/4 cup) of NutriRoot Granular. Woodchips tend to be high in carbon, so a nitrogen value is generally important, but in this case, I was interested in providing the roots with some nitrogen when they got to the bottom of the pot over time. If you have a pot-bound plant, that is, a plant that has circling roots, you will need to cut away some of that using pruning shears. Do this in each of four quadrants of the root ball. To the potting mix, add about 1/4 cup granular and blend. Next, place the plant in the center of the pot and fill with mix. Finally, once the plant is in place, water in thoroughly. It is advisable to shade your newly transplanted potted tree for a few days before setting it out in full sun.

In an upcoming blog, we’ll feature some tree injection practices, analyses and new field studies with Evan Sorger, Research Associate and Lab Tech.

~Signing off for now, Joe