Homegrown Garden Amendments

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By Nigel Palmer | Apr 23, 2021

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Adobe Stock/fotolesnik

The nutrient needs of plants change during their growth cycle. Germination, vegetative growth, reproduction, and senescence each requires its own unique array of minerals to support the metabolic processes taking place in the plant during that growth phase. Thus, each growth phase is a unique opportunity to significantly affect overall plant health. Learn what minerals are needed during these key development phases and the amendments available that’ll provide them.

Procuring Good Seeds

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Image Adobe Stock/Corinne Hill

The nutrition and environmental health of the first weeks of a plant’s life defines its overall development capacity.

Before focusing on how to optimize plant performance in the various stages of growth, first consider the impact of seed quality on growth. All seeds aren’t the same: Some batches of seed are of better quality than others; some are open-pollinated types that’ll reproduce true to type; some are hybrids; some are genetically modified. Selecting and saving good seeds is important when the goal is to grow high-quality food. Next year’s seeds may be improved if the parent plants are grown in the right mineral and biological soil conditions. Select the best-quality seeds available to you and sow them.

Saving seeds from the garden is a worthy endeavor. However, keep in mind that seeds produced by hybrid plants may not exhibit the same characteristics in following generations. Additionally, avoid saving seed from genetically modified varieties. Many are patented.


Purchasing seeds from reputable sources is a better alternative than buying any old seeds available on the seed rack. Saving and trading seeds with other gardeners is better still. Saving seeds is a natural selection process that allows the seed strain to become accustomed to a specific environment. In many cases, it’s easy and worth doing just to see the results. Saving seeds of a particular variety for several generations will result in a crop that has gradually adjusted to local soil and climate characteristics.

Heirloom seeds are a good place to start. These are plants of the past whose seeds were saved by growers because the plants exhibited desirable qualities. Local heirloom varieties may already be suited to the local climate, and perhaps even to the local soil type. Wild seeds are the least adulterated choices and include the seeds of edible weeds that grow locally: stinging nettle, dandelion, purslane, and lambsquarters, to name a few. These plants are nutritious, easy to grow, make great cover crops, may be eaten or used to make powerful amendments, and grow like weeds!

The Seedling Stage

Seed germination is the most important development phase of a plant, and the one with the most impact on its overall health. The challenge for gardeners and farmers is to eliminate any stressors that a plant may encounter throughout its life so that it may reach its genetic potential and produce seeds of better quality than the seed that started the season. Just as the nutrition and environmental health of the first two years of a child’s life define many of their developmental capacities, so do the first weeks of a plant’s life. Initial seed development, from sprouting to framing, defines a plant’s overall developmental capacity.

The quality of the environment and available nutrition at the time of seed germination determines the number, size, and quality of the fruit the plant will eventually produce. Cell division and cell growth that occur during germination require adequate proportions of calcium, potassium, boron, and manganese, and without success at this early stage, a plant can’t produce high-quality fruits.

Calcium may be found in limestone quarry rock dusts; fermented plant juice (FPJ) of nettle, dandelion, or sassafras leaves (see “Using Fermented Plant Juice,” below); vinegar extractions of eggshells, oyster shells, or cow bones; and leaf mold-fermented carrot tops. Potassium is found in these amendments as well in slightly different proportions. Boron can be found in vinegar extractions of oyster shells and cow bones and the FPJ of stinging nettle, chickweed, and leaf mold-fermented carrot tops. Manganese may be found in some basalt quarry rock dusts and in the FPJ of quack grass, dandelion, stinging nettle, or sassafras leaves.

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Image Adobe Stoke/M. Dörr & M. Frommherz

Make sure that you’ve met your plant’s optimal soil temperature for the best growth.

In order to be sure that the seeds get all the nutrition required from the start, soak them for 10 to 15 minutes in a solution of mineral-enriched water. Stinging nettle or dandelion FPJ provides a broad spectrum of minerals and other beneficial compounds all in plant-available forms. Soaking the seeds in a leaf mold-fermented amendment of the same plant would provide them with minerals and other beneficial compounds unique to that plant.

Large seeds, such as beet seeds, are relatively easy to soak and remove from the soaking jar to plant. Small seeds may be more difficult. Transferring individual wet seeds into small pots for indoor growing is relatively straightforward, but when direct-sowing small seeds outdoors, such as carrot seeds, first cast the unsoaked seeds onto the soil, and then water the bed with the mineral amendment solution. Repeated applications of water-soluble amendments will ensure that minerals are available during germination.

After sowing, continue applying mineral-enriched good water to the seeds and sprouts, especially during the first few weeks of growth. Remember that these plant-based amendments contain minerals in plant-available forms, as well as a broad spectrum of other compounds that’ll nurture the plants.

Biology may also be added to the soil a week or two prior to planting or transplanting in order to establish a rich biological environment for roots to interact with as soon as they enter the ground. Leaf mold provides the most diverse selection of local biology, but lactic acid bacteria or raw milk may be used as well. Once roots have become established and leaves unfurl, the plant will use some of the energy created during photosynthesis to selectively feed the soil biology, turning the ecosystem into its own digestive system. Experiment with various recipes and timing of application, and keep records of what you try to compare results.

Every crop has an optimal soil temperature for germination and growth. Make sure these temperatures are met to give the plant the best opportunity to thrive. Using a heat mat is the easiest way to attain optimal soil temperatures when starting seeds inside. A feedback system allows the soil to be kept at that optimal temperature night and day. Outdoors, use a thermometer to monitor soil temperature, and wait for the right temperature range before you plant.

The Vegetative Stage

For vegetative crops, such as lettuce, kale, and spinach, photosynthetic efficiency is a limiting factor to growth. Magnesium, iron, manganese, and phosphorus are needed to maximize photosynthetic efficiency. Once seedlings have begun to photosynthesize, apply these minerals as foliar sprays. Sources of magnesium include the vinegar extraction of cow bones, FPJ of stinging nettle or dandelion, and leaf mold-fermented dandelion or carrot tops. Iron, although present in the soil, is often not in a form that plants can utilize. Leaf mold-fermented carrot tops and the FPJ of dandelion, quack grass, and fruits contain iron in forms that the plant can use. As noted in “The Seedling Stage,” sources of manganese include some basalt quarry rock dusts and the FPJ of quack grass, dandelion, stinging nettle, or sassafras leaves. Phosphorus is available in the vinegar extraction of cow bones, FPJ of fruits, and leaf mold-fermented carrot tops.

During vegetative growth, observe the leaves for indications of mineral deficiencies. As soon as you notice a deficiency, apply a foliar spray or drench the plants and soil to address the problem. Biological amendments may be used to stimulate the ecosystem. Since most of the amendment recipes described here have plant-based, broad-spectrum mineral proportions, the risks of toxicity are lower than if using commercially produced single-element mineral compounds, especially in the case of trace minerals needed in concentrations as small as single-digit parts per million.

The Reproductive Stage

During the reproductive phase, plant nutrition priorities change. Mineral and nutrient needs of the flowers and fruit become primary, and minerals and nutrients are sometimes relocated from the leaves and stalks. Carbohydrates produced via photosynthesis are also prioritized to the flowers and fruit. Calcium-rich foliar sprays or drenches made with vinegar extractions can facilitate this nutrient flow to the fruit sink.

The stage just before a plant drops its leaves is an opportunity to provide nutrients for next year’s life cycle. One example cited by plant nutrition expert John Kempf is a foliar spray of cobalt, which may delay senescence and thereby increase crop yield. Local sources of cobalt include the FPJ of peach, apple, and mugwort. A vinegar extraction of the FPJ residue may yield cobalt in a higher concentration.

Fermented Plant Juice

Everyone loves a refreshing, fermented, nutritious drink…–…even your garden! Take your fermentation skills out of the kitchen and into the garden by brewing fermented plant juice (FPJ). This shelf-stable garden amendment made from mineral-rich weeds will help your plants grow up big and strong by providing a broad spectrum of minerals and secondary compounds.

This recipe can be scaled to any volume. For example, it’ll take about 2 pounds of plant material to fill a 1-gallon crock. The ratio of plant material to sugar ranges from 1-to-1/2 to 1-to-1. The more moisture in the fermenting material, the more sugar is required.

I first learned how to ferment plants in this manner by experimenting with the technique described in Natural Farming: Agriculture Materials by Cho Ju-Young and Cho Han-kyu.

Tools & Materials

  • Scale
  • 2-quart crock or glass jar
  • Rock or glass of water
  • Clean dishcloth or equivalent
  • Funnel
  • Sieve
  • About 1/2 pound plant material
  • About 1/2 pound organic brown sugar
  • 1 quart glass jar


1. Pick plant leaves and stems early in the morning before the sun is up, while the dew is still on them. This is when the plant leaves have the most energy in them. By picking the leaves in the morning before the sun rises, this energy is captured for making FPJ. Lactic acid bacteria and yeasts are captured on the plant surfaces. Don’t wash the plants, and don’t harvest just after rain, because rainfall can also wash off lactic acid bacteria and yeasts. If conditions have been dry for several days, water the plants the day before you plan to gather material from them.

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Image Nigel Palmer

Step 2

2. Weigh the plant material, and add organic brown sugar. For relatively dry plants, start with a ratio by weight of 3 parts plant material and 2 parts organic brown sugar. For wetter ingredients, such as fruit, use a weight ratio of 1-to-1.

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Image Nigel Palmer

Step 3

3. Mix the plant material with the organic brown sugar in a large bowl. After mixing, move the mixture into the glass jar or crock, or place the unmixed plant material and sugar into the jar in alternating layers. A tall, narrow container will work better than a wide, shallow one. Cover the top surface of the material with a layer of sugar. Initiate fermentation by placing the rock or glass of water on top of the contents in the jar. Any item that’ll fit into the opening of the jar can be used as a weight, but avoid items made of plastic, or stainless steel or other metals. The weight of the added item will press the sugar and plant material together, initiating osmosis to draw moisture out of the plant material. Make sure the weight is clean. (Boil the rock before use, for instance.)

4. Cover the entire jar with the cloth, and store in a dry, well-ventilated area at room temperature (about 70 degrees Fahrenheit) and out of sunlight.

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Image Nigel Palmer

Step 5

5. Periodically check on the jar. Within hours, a brown liquid will begin to form at the bottom. When enough liquid has formed so that all of the plant material is submerged (this may take a day or so), remove the weight. Allow fermentation to proceed for several days, continuing to monitor the jar to be sure the plant material stays submerged. After about a week, the fermentation process will be complete. The contents will have a fragrance that’s unique and not off-putting. (I’ve left fermenting plant material sitting longer than this and still had a stable product, though eventually the contents in the jar will change into something else that may not be as useful. Experiment with the timing.)

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Image Nigel Palmer

Step 6

6. Place the funnel into the quart jar, and put the sieve atop the funnel. To strain the liquid from the plant matter, invert the fermentation container into the sieve so that the liquid drains freely into the quart jar. This setup provides sturdy support for a glass jar that’s 1/2 gallon in size or smaller. For a crock or other heavy container, create a different setup. (Some imagination may be required.)

7. Let the mixture drain for several hours, or overnight. Don’t attempt to squeeze residual liquid out of the plant material. The amount of liquid amendment produced will vary depending on how much moisture was in the plant matter at the start of the process. If foam appears on the top of the fermentation liquid after extraction, add more sugar to eliminate it. Record these details in your garden notebook for future reference.


8. Label containers with the plant type and parts used and the dates when fermentation began and ended. Add to your garden notebook the weights of plant and sugar used, the type of sugar, the time of day the plant was harvested, the containers used, and other information deemed appropriate. Store the containers in a well-ventilated, constant-temperature area out of sunlight.

This excerpt is from Nigel Palmer’s book The Regenerative Grower’s Guide to Garden Amendments (Chelsea Green Publishing, August 2020) and is reprinted with permission from the publisher.

Using Fermented Plant Juice

Fermented plant juices (FPJ) are easily made, shelf-stable, low-cost, sustainable, and regenerative mineral amendments. These products take advantage of the great mineral accumulators in our backyard…–…the weeds and those less-than-perfect end-of-the-season fruits. These amendments also contain other beneficial compounds besides minerals: enzymes and proteins, all in forms plants can use.

Start by using single-plant fermentations. Mineral-rich weeds, such as dandelion and stinging nettle, are good plants to try first, because they’re easily found, and their broad-spectrum mineral proportions and amounts provide a good food source for the healthy growth and development of many kinds of plants. Experiment making FPJ with other plants, recognizing that each plant type has unique characteristics that may be harnessed. (Use recipe, right, as a template.) Use these in conjunction with other amendments to facilitate specific plant growth periods. Take good notes on what you apply and the kind of results you see. FPJ can form the basis of your short-term mineralization efforts throughout the growing season.

Apply FPJ as a foliar spray, or apply as a drench to feed plant roots and soil biology. The optimal dilution ratio will depend on the type of plant fermented and the needs of the plant being fed. Start with dilution ratios of 1-to-1,000 or 1-to-500. Diluting FPJ in a 5-gallon bucket filled with about 4 gallons of water works well, because there’s enough space at the top to allow for vigorous stirring. One tablespoon of FPJ added to 4 gallons of water is a 1-to-1,000 ratio, 2 tablespoons a 1-to-500 ratio. If a quart of FPJ is made in the kitchen and diluted 1-to-500, this will make 500 quarts of amendment…–…that’s 125 gallons! Small amounts of this product go a long way.

FPJ is also valuable for encouraging germination. Seeds may be soaked prior to planting. Dilute the FPJ in the same ratio as above, and soak seeds for several minutes prior to planting so that the minerals needed for growth are available as soon as sprouting occurs. The continued exposure to FPJ will ensure that minerals are available in forms that the young seedlings can access, reducing potential sources of stress as a result of poor nutrition.

soil science

Soil Science for Gardeners is an accessible, science-based guide to understanding soil fertility and, in particular, the rhizosphere — the thin layer of liquid and soil surrounding plant roots that’s vital to plant health. Author Robert Pavlis debunks common soil myths, explores the rhizosphere, and provides a personalized soil fertility improvement program in this three-part popular science guidebook.

This title is available at the Grit store or by calling 866-803-7096. Item #10182.

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