How Plant Fertilizers Work

Understanding how plant fertilizers work begins with an understanding of the nutrients that plants need. And the focus of this short article is to cast a ray of light on plant fertilizers, which include both synthetic and organic fertilizers. Of course, there’s much more to gardening than simply plant nutrients and plant growth, but let’s begin with the basic science of how plant fertilizers work - both synthetic and organic. 

Every plant  - from a blade of grass to a towering oak tree - needs varying amounts of the three primary elements Nitrogen, Phosphorous, and Potassium, at different times during the plant’s life cycle. For optimum health, plants do require other secondary elements and trace minerals, but these three primary elements from the periodic table are the most important. Fertilizer labels display these three elements using their international symbols - N for Nitrogen, P for Phosphorous, and K for Potassium - along with a number that indicates the percentage of the fertilizer that’s made up of each element. For example, if a  fertilizer label reads 10-5-3 , ten percent of the bag’s contents is Nitrogen, five percent Phosphorous, and three percent is Potassium. These numbers, often listed along with an application rate on the label, are there to help you apply the right amount of fertilizer in your garden. 

Simply put, all fertilizers  - both chemical and organic - work by delivering N, P and K to plants, and these three primary elements can only be absorbed by plants after the elements have been broken down into molecular form. Synthetic fertilizers have been engineered to dissolve quickly into molecular form, and the accelerated plant growth induced by these fast-acting fertilizers is attractive to many commercial growers. After all, that next crop of plants doesn’t really know or care how it gets its supply of Nitrogen, Phosphorous, and Potassium. So why not get to harvest time faster, and with more profit? Plenty of commercial growers see it that way.

Organic fertilizers depend on microorganisms naturally present in the soil to break the product down into molecular form, and the pace of this microbial activity is contingent on the temperature of the soil. So, not surprisingly, livestock manures, bat guano, bone meal, blood meal, kelp, meal, alfalfa meal, etc. etc. etc., all take far longer to break down into molecular form than water-soluble synthetic fertilizers. So why would a grower use a fertilizer that works more slowly and may even cost more?

Here’s where difference between the two growing methods sharply diverges. While chemical fertilizers can churn out fast, shiny crop yields for a time, often that water-solubility that delivers nutrients in the blink of an eye, also means that those nutrients will just as rapidly leach out of the soil. And over time, this nutrient leaching process can leave behind high levels of salts in the soil. This frequently alters soil pH levels, making the soil less suitable for cultivation, or sometimes even completely sterile, and only restored with tremendous effort. Synthetic fertilizers can also harm or entirely destroy beneficial soil organisms like earth worms and soil microbes, but these organisms aren’t needed to convert synthetic fertilizer into molecular form, and therefore often play little or no role in the growth of a chemically fertilized crop.

Meanwhile, organic gardening places tremendous emphasis on the relationship that plants have with the many beneficial organisms that are naturally present in the soil. You might even say that these soil organisms, including earth worms and microbes, are everything to an organic gardener. After all, organically-grown plants would receive no nutrients without the presence of these essential organisms that break down organic fertilizer into molecular form. Now, it’s true that organically-grown crops do grow more slowly than those fueled by synthetic fertilizers. But consider that with the careful addition of organic material, including manures, humus, and compost, organic soil -  while under continuous cultivation - can actually become more fertile over time. 

Put simply, one method could eventually result in soil sterility while another could lead to improved soil fertility. That's quite a difference, and well worth your thoughtful consideration.

And, it's no secret where we fall on this topic - after all, we’re Microfarm Organic Gardens. Our focus is backyard edible gardening, where it’s hard to picture a grower in such a hurry that she would choose a synthetic fertilizer over an organic option for an edible garden planted to feed her family healthy produce. 

But commercial agriculture is another story, and far too vast a political topic to be explored in this short article. So, true to the title of this piece, we’ve briefly weighed the specifics of how fertilizers work - both chemical and organic. Interested in learning more? Hopefully so, and we’d be delighted if you used this text as a starting point for further research on the topic. Let prudence be your guide in learning about and using fertilizers. And remember; gardening without an understanding or appreciation of your soil, would be roughly equivalent to learning all about various medical drugs and remedies without first seeking any understanding of what the human body requires for optimum health.

Goodbye Sore Backs, Hello Kitchen Garden

William and Elizabeth McKee have a cheerfulness and contagious optimism that could thaw half of Siberia.  And it’s no surprise that when disease finally forced the removal of two colossal shade trees on the couple’s Chantilly property, they quickly separated the silver lining from the understandable disappointment. Areas of the their yard that once nurtured delicate, shade-loving ornamental plant varieties, were now opened up to hours of direct sunlight. So the McKee’s decided to plant an organic garden.  

And the site that they selected for their new garden had all the key advantages that we look for when choosing an edible garden site; Plenty of sunlight. A water supply nearby. And a very short walk to the kitchen. With these essential considerations working in their favor, plus a worthy effort with a garden hoe and lots of organic compost, an area along the left side of their home became an organic garden. Tomatoes and peppers thrived there,  proving that there was, indeed, more than enough sunlight to grow any edible variety, even heat-loving summer vegetables.

But that success was hard-earned and came at the expense of the perpetual struggle against a stubborn clay soil that resisted attempts to improve drainage and aeration, swallowing up compost and other organic soil amendments, with only modest improvements in soil quality to show for it.

By the end of the summer, two sore backs and a sprawling, weed-choked garden seemed to cry out together, “ There has to be a better way!” 

There is a better way, and the McKee’s soon discovered that cedar raised beds were the answer. After searching around for the right raised bed design - carefully reviewing raised bed kits, and other raised beds of various style and construction - they at last selected our 18”- tall Kitchen Garden raised bed design. All that hacking away in vain at a churlish slab of clay was finally disappearing in the rearview mirror. 

The Kitchen Garden is made with aromatic red cedar  - a naturally durable wood that’s famously long lasting in outdoor projects like raised beds, chicken coops, greenhouses, and compost bins. Red Cedar’s well-founded reputation for resistance to insects and decay is no trendy exaggeration; it’s been well-earned over the eons of this special tree’s service to humanity. 

The McKees’ organic garden features two raised beds. One is a U-shaped Kitchen Garden that measures 3’ wide, 9’ across the back and 6’ long on the sides. Just across the flagstone pathway sits a 3’x 9’ Kitchen Garden raised bed.

One of the key advantage of the 18” height of the kitchen garden is the reduced wear and tear on a gardener’s body. With its sturdy seating cap placed at the standard height of a chair or bench seat, the Kitchen Garden design makes it easy to relax and tend your garden.

Another key advantage of the 18” height of the Kitchen Garden design is the large volume of premium organic soil available to nourish plants. Like all of our Kitchen Garden raised beds, the McKee’s new raised beds are filled with a lightweight organic soil blend that allows water to easily drain through, helping avoid the problems that come along with perpetually soggy soil. This special horticultural grow media is a blend of mushroom compost, shredded pine bark fines, and slate pebbles, and allows plant roots to quickly grow through the soil, and take in air and nutrients. 

And it was an easy decision to add drip irrigation to the garden. Both William and Elizabeth work full time, and they heartily appreciated the amount of time the automated drip irrigation watering system will save. Both raised are fitted with grids of 1/2” drip tubing, with emitters spaced 12” apart, and that each deliver about a gallon of water per hour. These irrigation grids are buried a few inches below the soil surface, which conserves water by delivering it right to the plant root zone. In raised beds, this buried-drip irrigation method is far preferable to above- ground irrigation sprayers that often put too much water on the plant foliage instead of the roots. Above-ground irrigation sprayers tend to keep plant foliage perpetually wet, encouraging fungal diseases in edible plant varieties, and potentially scalding plants and wasting water through evaporation on hot days. The drip tubing in both raised beds is connected underground and routed to the nearby spigot, where watering is controlled by a battery-powered timer.

With the raised beds leveled, staked down, and filled with organic soil, and the automated drip irrigation system programmed, it’s time for the McKees to start planting. And what does the future hold for Elizabeth and William’s new garden? Tasty organic produce? Fresh air and sunshine? New gardening adventures together? Surely all this and more.

But the sore backs and the clash with clay are finally a thing of the past. 

Backyard Compost Essentials

Making your own organic compost has to be one of the least complicated garden projects you’ll ever take on. And it’s no exaggeration to say that it’s one of the most useful steps you can take to improve the health of your garden. Simply put, the quality of your homemade organic compost will almost surely far exceed anything that can be purchased in a bag.

 
So the sooner you can turn all those orange peels, egg shells, leaves, and grass clippings into organic compost and add it to your garden, the better. And if you consider a few simple guidelines, you’ll speed up a process that Nature already has well under control. Simply pile on the right things and avoid adding the wrong things to your compost bin, and you really can’t fail.

  

Start with Layers

Your compost pile will decompose faster when it has a fairly even combination of nitrogen-based and carbon-based organic material. These are often referred to as ‘green’ ( nitrogen-based ) and ‘brown’ (carbon-based) materials, and too much of one or the other can result in unpleasant odor, and a far slower decomposition process. Examples of nitrogen-based material include grass clippings, banana peels and coffee grinds. Dry, fallen leaves are a common source of carbon-based material for your compost pile. 

Building your compost pile with alternating layers of nitrogen and carbon based materials is an excellent way to ensure the right ratio between these materials. Adding a shovelful of native soil and a handful of bonemeal with each layer helps ensure the presence and health of the hardworking aerobic microorganisms that are eager to break down the material. Now, layering does make your initial compost pile nice and neat. But, alas -  the first time you turn the compost pile, those tidy layers will get all mixed up. But not to worry, because maintaining layers isn’t essential for the material to decompose. As long as you’ve added the right things in the right ratio, the stuff in your compost pile will still break down, layers or no layers.

 

Water or Cover as Needed

Your gardening intuition probably tells you that the material in your compost pile should be somewhere between bone-dry and soaking wet. And if so, you should trust that astute inner  voice. The idea is to add water to the compost pile during prolonged dry weather, or cover the pile as needed during extremely wet weather, to maintain the moist consistency of a wrung-out sponge. This will foster the well-being of the aerobic microbes that break down the material, and help prevent plant nutrients from leaching out of the compost pile during heavy rains.

 

Turn the Material to Speed up the Process

Consider that turning the compost pile introduces oxygen, increasing the output of the aerobic organisms that continuously work to break down the material. Turn the material in the center of the pile outward, add a splash of water and perhaps a handful of bone meal, and you’ll help those hardworking aerobic microbes make good use of their new supply of oxygen. Turning your compost pile is not a wasted effort, and and the more often you turn the pile, the faster the material will break down. 

But don’t fret if the idea of turning all that material doesn’t excite you. Turning the compost pile simply speeds up a natural process that will happen anyway - with or without your help.

The Health Benefits of Raw Produce Vs. Cooked Produce

Fresh. Organic. Packed with flavor. Harvested straight from the garden, most fruits and vegetables are richest in fiber and at their peak of their antioxidant, mineral, and vitamin content.

And it would seem logical that eating your fresh produce uncooked would surely make it more nutritious. After all, wouldn’t the process of heating damage or destroy the nutrients that are naturally present in the produce?

The short answer is ‘not always’. 

In fact, research shows that some vegetable varieties actually offer new health benefits when cooked. During the process of cooking, cell walls are weakened or completely broken through, allowing more soluble vitamins, minerals and antioxidants to become available to the body. And many of these newly-released nutrients are even more readily-available when cooked along with a healthy fat source like olive oil. 

But there is a trade off, and the nutrition gained from cooked produce, usually come with the loss of the health benefits from eating the same vegetable variety uncooked.

For example, cooking tomatoes increases the availability of a cancer-fighting carotenoid called lycopene, but diminishes the amount of vitamin C and potassium present when eating tomatoes raw. And the beneficial antioxidant lutein that’s present in kale and spinach is absorbed by the body far more efficiently when these leafy greens are cooked along with a fat source like olive oil or butter. Just consider the amount of healthy fat present, and, if cooking with oil, remember not to exceed the oil’s smoke point. When cooking with olive oil, for example, warm the oil in a pan on medium heat, then add and quickly cook your produce, perhaps covering with a lid to speed up the process.  

Other studies have shown that cooking organic produce can increase the amount of iron that we absorb when eating many fruit and vegetable varieties. Broccoli, for example, had five times more available iron when cooked, but also lost about as much of its glucosinates - substances present in raw broccoli that are believed to block the growth of cancer cells.

So which is the healthier way to eat your backyard produce, cooked or raw? It seems too close to tell, but that doesn’t really matter, because you can simply include a combination of both in your diet.

Just remember that raw vegetables offer far more fiber than cooked produce. Fiber helps lower cholesterol and regulate blood sugar, and keeps your digestive system healthy. And avoid the temptation to see juicing vegetables as a substitute for eating them uncooked. Research shows that eating raw vegetables has far more health benefits than juicing them, which results in the loss of fiber, nutrients, and vitamins that are found in the skins of many varieties. 

And when you do cook your organic produce, consider these tips to minimize nutrient loss during the process.

-Whenever possible, don’t remove the vegetable’s skin before cooking ; the nutrients of many vegetable varieties are found in the skin.

-Try to time your harvest so that the produce is cooked and served right afterwards. This will help maximize the nutritional value of your fresh produce.

-Steaming is perhaps the best cooking method, but produce that’s roasted or grilled will also retain more nutrients than other cooking methods. When steaming produce, use a small amount of water to help minimized the loss of nutrients.

-For vegetable varieties that must be chopped before cooking, cut the pieces in the largest chunks possible. This helps minimize air exposure which reduces the amount of vitamins left after the produce is cooked.

-Cove the pot or pan with a lid, and remove from heat as soon as the vegetables are just tender. These steps help minimize cooking time so that fewer nutrients are lost during the process. 

Robust and Refined; The Chisolms' 8' Tall Deer Enclosure

Most organic gardeners are happy to share a little of their fresh produce with the area wildlife.  But even the most patient growers can get frustrated to find their entire garden continually gnawed down to the ground. Sometimes squirrels are the culprits, and other times, those nibbled leaves are the work of rabbits. And even in urban and suburban areas, but especially in outer-lying neighborhoods with larger lots, deer are the guilty parties. Under the cover of darkness, deer come in hungry and leave happy -  razing your carefully nurtured organic garden down to the very roots. 

Now, sometimes scent-based deer deterrents do the trick, and you should count yourself fortunate if sprays, granules, hair clippings, etc. really do keep deer out of your garden. 

But these methods aren’t always effective, and the most reliable solution is a fence or enclosure around your garden that’s tall enough to keep deer from jumping over.  Deer fence designs and prices vary as widely as the weather, but they should all be 8’ tall or higher to keep deer out of your garden.

For large gardens in rural areas, and on farms, low-cost deer fencing kits work just fine. These kits usually consist of plastic netting stretched along metal poles that have been anchored to the ground, and a large area of crops can be protected at a relatively low cost.

But if you live in town, these effective, if visually humble designs aren’t likely to win any praise from the neighbors, or an HOA if you have one. Chances are you’ve invested in the appearance of your own landscape - perhaps even one or more cedar raised beds -  and an 8’ tall deer enclosure design would have to do more than simply keep deer out of your garden;  it would also have to enhance the visual appeal of your existing landscape.

And this was the case with Dan and Lynetta Chisolm, seasoned organic gardeners who live in an upscale neighborhood on the North side of Charlotte, with an alert and active HOA. 

After growing their own organic produce in a ground-level garden for years, these two avid growers decided to invest in an elegant organic garden design that included five cedar raised beds with drip irrigation, and decorative white pea pebbles. 

The Chisolms’ new garden design was a big step up in visual appeal, and just looking at the 18” tall Kitchen Garden raised beds made even the idea of working in their garden seem far more comfortable.

But the 18” tall raised beds would also make it more comfortable for the neighborhood deer to feast on their produce, and a functional, but attractive deer fence was essential to protect their investment. 

Gladly, our 8’ tall garden enclosure design was swiftly approved by the neighborhood HOA. The enclosure is framed with 2”x4” rough-sawn red cedar, and wrapped with 1/2” hardware cloth mesh, giving the design a tremendous amount of strength as well as the visual appeal needed to win the approval of the HOA, and not to mention the neighbors, too. Red cedar and galvanized steel mesh are famously durable materials for outdoor projects like this, and the Chisolms can expect many, many years of service from their garden enclosure. And to minimize our time and impact on the job site, we built the enclosure in our workshop in sections, then joined the sections together around the newly completed raised beds, using structural steel screws. This kept the on-site assembly portion of the enclosure to only about three hours.

Strong. Elegant. And Effective. This project really came together, and Dan and Lynetta were very pleased with the finished product. And we were just as happy as they were to see their new raised bed design safe from all those stealthy deer. After all, we’re gardeners, too. We know all about the disappointment of a nibbled up harvest, and we also know the satisfaction of protecting your garden from hungry wildlife.