Your Homegrown Fertility Guide
Helping Growers Succeed…
Sustainably!
Let's talk about how you can create fertility for the farm and garden
Right in Your Own Backyard!
If you have ever desired to be more sustainable in the way you live and how you consume, then you must already have realized the impact that our everyday decisions have on the health and ecology of our planet. Creating homegrown fertility is an excellent way to take the next step in creating a more sustainable home and farm. The exciting truth is that we are surrounded by readily available plant fertility sources and need not look further than our own backyard to grow truly sustainable healthy crops.
Where do we find fertility sources?
Fertility is in the air around us and in ground beneath us. We have only to understand how to unlock these vital nutrients and make them absorbable by the plant beings we call our garden crops.
When we talk about plant fertility, what do we mean?
Along with the process of photosynthesis, it is necessary for a plant to uptake certain nutrients in order to complete its life cycle. There are "major nutrients" and "minor nutrients", which are also called "trace minerals" and last but certainly not least “Carbon”. The major nutrients are taken up by plants in lager quantities than the minor nutrients, which is why they are referred to as "major". Major nutrients are nitrogen, phosphorus and potassium (N-P-K) and a secondary class of major nutrients includes calcium and magnesium. Minor nutrients include iron, copper, zinc, iodine, selenium and many, many more. Carbon is indeed the difference between what you call as soil and what you call as dirt. Dirt is an inert collection of various minerals. Soil is the living strata where micro organisms, plants and the inert mineral geology interact. Carbon is fixed into the soil by plants through photosynthesis. It is exuded through their roots and collected in their fleshy tissue that is then distributed into the soil as the plant decays.
How do we access nitrogen?
Nitrogen is derived from the atmosphere and is fixed into the soil in a few ways. Certain weather patterns put modest amounts of nitrogen into the soil. Rain and snowmelt carry ammonia (a form of nitrogen) and nitrate that has been broken down into soluble form by lightning storms. Certain plants operating under a symbiotic relationship with certain soil bacteria are able to fix atmospheric nitrogen in the soil and convert it into forms usable by plants. These plants are called legumes. Legumes are a family of plants that includes peas, beans, clovers, vetches and many more. The legume family is characterized by all having the ability to partner with soil bacteria to fix atmospheric nitrogen. There are many shrubs and bushes (non-legumes) that fix nitrogen as well.
Legumes are capable of providing the necessary amount of soil nitrogen for agricultural plants to thrive. When legumes, or any plant for that matter, is used specifically for the purpose of fertilizing or recycling fertility in an agricultural setting it is known as "cover cropping". Learning how to use cover crops is an essential asset to a grower who wants to farm with homegrown fertility. We will discuss cover cropping later in this article.
After nitrogen is fixed into the soil, either by rain, snowmelt, or leguminous cover crops, other plants absorb this nitrogen into their bodies. When a plant dies and decomposes, this nitrogen is cycled back into the soil, for new plants to take up, and so the cycle continues. During this process a small amount of nitrogen is released into the atmosphere.
What are other ways we can provide our crops with nitrogen?
Legume cover crops are one of the best ways to provide nitrogen to soil.
Compost is a modest but significant source of nitrogen. It has a general nutrient analysis of 1-1-1 per 1/2 inch according to some sources. That means 1 unit of nitrogen, 1 unit of phosphorus, and 1 unit of potassium. Our experience with compost is that a good quality compost contains almost all the nutritional needs of any given crop, provided the right amount of compost is applied.
A nitrogen tea can be made out of submerging grass clippings, garden weeds, all leafy green matter, and food waste in water. Keep this organic material soaking in a covered container for 5 to 7 days (until it smells really bad!) and you will have a rich and potent liquid nitrogen fertilizer to feed your crops.
How much nitrogen you use in a garden bed depends on what crops you are growing. A legume cover crop and a nice home made compost will always yield fantastic results. If you notice yellowing leaves or stunted and slow growth, and you suspect low nitrogen to be the cause, nitrogen teas can amend the issue. It may take a couple of feedings to notice a return to healthy green growth.
Here we have planted an early spring field pea cover crop to enrich the soil with nitrogen. After the peas developed their nitrogen nodules, we dug furrows to direct seed or transplant into. We then lightly trampled the peas to create rows of mulch between our furrows.
So what about major nutrients?
Luckily for us, major nutrients are available in organic forms that we all recognize and that are abundantly available all around us. Indeed many of us have access to these materials right in our own back yard. Here we will talk about some of the most significant organic sources of major nutrients; tree leaves, grasses and pasture plant species, ramial wood chips and wood ash.
Tree-based Fertility
Hardwood trees contain a dazzling array of minerals. They use their mighty root systems to plunge deep into the lower strata of the earth to bring up minerals and distribute them on the surface in the form of leaves, branches, and bark. Three major sources of garden fertility can be derived from trees and shrubs.
Leaves: Leaves contain almost every nutrient plants need for growth in varying amounts, depending on the species and on the parent material or parent rocks that it grows on. The geology under the tree's feet determines what it can bring up in the first place. Leaves can be used in an extremely high quality compost and/or as mulch in garden beds. As mulch, they smother weeds and retain moisture as well as host many types of beneficial fungal communities. Many new university studies have been put out showing that high concentrations of leaves added to soil over long periods of time do not have a significant impact on soil PH.
Wood chips (in particular ramial chips): Ramial chips are newest growth of branches from hardwoods under 4 inches in diameter. Saplings are also considered as ramial growth. Trees sequester much of the nutrients they take up in their new growth. A part of Shambho Farm’s homegrown fertility plan includes managing a 1/6 acre grove of saplings that we regularly thin to harvest for ramial chips. This managed area is also a protected haven for songbirds and other small woodland creatures. Ramial chips can be used in a high quality compost as well as a mulch around fruit trees and shrubs. Some people do even use ramial chips as mulch in their garden beds, we have not experimented with that however.
Wood ash: Woodash contains a lot of potassium, a bit of phosphorus, and a vast array of "minor nutrients". Heating a home with a wood stove will provide you with all of the woodash you will need to feed your plants come spring time. The general analysis of wood ash is 0-1-3. We will put emphasis again of the dazzling array of “minor nutrients”! Wood ash will change the PH of your soil if used in high enough quantities. It takes twice as much woodash to have the same alkalizing effect as Limestone. We sprinkle a small amount with just about everything we plant. Enough to deliver the goodness in the ash without having a real effect on PH. It is always best to take routine samples of your soil so you can monitor the changes. Soil is a dynamic process that is ever changing.
Pasture Grasses and Other Pasture Species
Another one of the best sources of major (and minor) nutrients are pasture grasses and broadleaf pasture species. Grasses develop complex perennial root systems that accumulate and recycle nutrients. Broadleaf biennial and perennial plants such as comfrey, burdock, lupine and mullein are amazing bio-accumulators with long taproots that can delve deep into the soil and bring up nutrients that are far out of the reach of more shallow rooted plant species. By using organic matter from a pasture you can add tremendous amounts of nutrients to your garden. We cut from our newly planted orchard pasture (an area of about 1/2 acre). Wether you have a swath of wild grasses, or a lawn, you too can supercharge your compost with the bounty of pasture fertility. Even grass clippings will provide many nutrients and can be used in compost and as mulch.
Any organic material you can get your hands on will add to the net fertility of your garden beds, as well as build organic matter and boost microbial activity. We do urge you to explore permaculture growing techniques that use particularly efficient landscape plants, herbs, and pasture species to double as bio-accumulators for fertility.
Where can we find sources of minor nutrients?
The sources of fertility we have already gone over are also fantastic sources of minor nutrients. When you use mineral-rich earth materials to fertilize and nourish your crop beds, you are taking an active role to reverse the separatist mentality and unsustainable methods of modern industrial agriculture. This mentality divides everything into bits and pieces, ships it far away, and desperately tries to reassemble it in the field. It has trickled down and taken root even in our approach to home gardening. Homegrown fertility is by its nature a far more holistic approach to farming and gardening. By emulating nature and natural ecosystems we do not need to isolate our agricultural inputs. Creating organic matter, sourcing minerals, promoting fungal activity, and supporting microbial life and human wellbeing can become a united effort in an ever-giving cycle.
There are some instances however, where you may find in your given location some minerals are just flat out missing from the earth under your feet due to the make-up of the parent rock material and the glacial movements of long ago. In such cases, azomite and other similar bagged trace mineral amendments can help you to adjust your soils levels.
Thinning our sapling grove to make ramial wood chips.
What about carbon?
Carbon is as important as all of the major and minor nutrients listed above. Carbon is the most vital building block of soil. Plants take carbon from the atmosphere and incorporate it into their bodies. Minerals that plants absorbs during their life are locked within their carbon bodies which is then returned to the soil. Soil microbes feast on this carbon plant material and break everything down into a rich nutrient laden material called humus (pronounced HEW-muhs). This is one of two major biological processes that are responsible for creating soil and recycling fertility.
All of the materials we have previously discussed are also fantastic sources of soil carbon and some of them even add a source of long term carbon such as the tough ramial wood chips and woody pasture species.
How do we fertilize with cover crops?
We have already talked about leguminous crops and their role in fertility building. What other cover crops can be used as fertilizer?
With the exception of legumes and a handful of others, the role of a cover crop is to “recycle” fertility, not necessarily create fertility. Most common cover crop plants are fairly shallow rooted and scavenge to the extent they can reach for nutrients that are starting to run away into the lower strata of soil via rainfall. They take up available nutrients from the soil that are starting to leach, lock up and stabilize these nutrients in their plant bodies, and redistribute them onto the top layers of soil when they die and decompose.
Some of the best and easiest cover crops for nutrient ‘recycling’ are oats, wheat, millet, mustard and buckwheat. Some cover crops, such as most clover varieties, are biennials meaning they are planted late summer/fall and start to grow back in the spring of the following year. These biennial types of clover tend to fix more nitrogen than annual species and will develop a long tap root for scavenging available nutrients deep into the soil. We have had great success with a multitude of clover varieties.
A cover crop of mustard not only recycles nutrients but it contains chemical compounds which act as a biofumigant. This is a wonderful way to heal from microbial dysbiosis and soil-borne diseases.
There are certain cover crops however, that in addition to recycling nutrients are able to dissolve rock and generate nutrients for plants that is otherwise unavailable to crops. There is still much disagreement and conflicting information amongst the scientific community on how effective certain cover crops are at doing this, but we know for sure they can do this to some extent. Buckwheat, tillage radish, and sweet clover are a few cover crops that may be able to dissolve rock and turn these locked up minerals into bio-available nutrition for our garden crops.
Buckwheat is known to be able to dissolve phosphorus, which most other plants cannot do, and convert it into a useable form.
Tillage radish and sweet clover may have a similar ability if allowed to fully mature, which can take some time. They both have very long taproots and are said to be well suited to extract insoluble minerals such as phosphorus and potassium from lower levels of soil strata.
Here we see our wild woodland ferns that we have harvested to use as mulch flanked on the right by a cover crop of clover. Ferns have the ability to uptake silicate mineral particles from the soil and incorporate it into their bodies, thus distributing it as an available plant nutrient when they decompose.
Cover cropping is a powerful and harmonious way to fertilize your growing spaces. We recommend using many different types of cover crops as they all offer different benefits to your garden beds. Using different types of cover crops will allow you to be more versatile as they all require different days to maturity and have special considerations. One may work where another does not and vice versa. Days to maturity is a prime consideration when determining which cover crops to use at a given point in the growing season. There also are many benefits beyond fertilizing that certain cover crops offer including weed control, insect/pest deterrents, and soil bacteria/fungus eradication.
An All-Inclusive Approach
We incorporate all of the fertility sources we have discussed in this article simultaneously on our farm. We never use one form of fertility in place of the other and use all forms in combination with each other. This is a pillar of our home grown fertility. We have come to experience the strength of homegrown fertility lies in the diversity of our resources and the steady application of them all at different times within the season.
How do I know that it’s working?
You will learn a lot by simply observing your plants and how they respond to what plant food you give them. If you want to gauge exactly what the nutrient levels of your soil are and how it is responding to your amendments, then routine soil testing is a must. You can see about getting a test through your state university’s agricultural extension.
Let’s create a scenario to put all of this growing information into action.
(This scenario is specific to regions that experience freezing temperatures in the winter months.)
It is early spring and we have just direct sowed a crop of summer carrots. By the late summer, after the carrots are harvested, we have any number of options of how we can improve the soil for next year’s tomato crop.
At this time in the season we could sow a buckwheat or pea cover crop. Buckwheat is frost sensitive but it is fast growing which makes it an excellent choice for a late season cover crop. Even 30 to 60 days is an adequate amount of time to derive benefits from buckwheat. The buckwheat would be killed by the first frost and at that time we can cut down the buckwheat and leave it there to breakdown over winter. Peas are another excellent choice at this time of the growing season because they are tolerant of a bit of frost allowing them to fix nitrogen for quite some time until they are killed by a hard frost during the onset of winter.
Early in the spring, we can surface sow a pea cover crop and lightly cover with an organic mulch. This will hold moisture and allow peas to germinate quickly. (We also recommend soaking peas overnight before sowing, as it commences germination.)
Once tomatoes are ready to transplant (check last frost date for your area), cut the peas back and leave the pea plants as mulch over the garden bed. You can add more mulch (leaves, grasses, etc.) over them if you so desire. Keeping this mulch in place over the entire bed, burrow a planting hole through the mulch for each tomato plant and add a sprinkle of wood ash and a good amount of compost. An optional recommendation is to water with a compost/nitrogen tea a couple times once tomatoes are rooted, a couple days after transplanting. Watering too soon with a concentrated nitrogen tea will burn the delicate roots of a transplant, so best to give it a little bit of time.
As you can see, creating homegrown fertility can be quite a simple and fun process. With a bit of planning and care, your gardens will be building soil fertility and organic matter on their own! No bagged fertilizer necessary, just locally sourced goodness.
Happy Growing!
Oat and Mustard Cover Crop