Soil Elements & Amendments

What are the elements your soil is comprised of? What amendments need to be added? Read on for more info….


Structurally, plants are comprised of Carbon, Hydrogen and Oxygen. These are absorbed from the environment naturally. But to grow your veggies or herbs to full-size, good health, and peak productivity, you need to ensure that your soil has these elements:


  1. NITROGEN – This promotes overall plant health and ensures good leafy growth. Though nitrogen is easily available in air, it is less readily accessible in soil. Signs of nitrogen deficiency are limp, pallid, and dull foliage. While Manure has high rates of Nitrogen, much of it is lost when applied to soil (mineralization) and leaching into soil (denitrification)*. Thus the best organic amendment to increase nitrogen levels is Compost.
  2. POTASSIUM – This synthesizes protein, helping your plant grow faster, stronger and disease-resistant. Signs of potassium deficiency are yellow and brown spots or veins, in plant leaves. The best organic amendments to increase potassium levels are Compost, Wood Ash (aka Potash) or Neem Cake & other Neem Products.
  3. PHOSPHORUS – This gives your plant energy, helping it grow quickly from seed to plant, and then enhance its flowering and fruiting. It is most easily accessed by the plant when soil pH is close to 6.5. Signs of phosphorus deficiency are stunted growth, small and acidic-tasting fruit, and older leaves with bluish or purplish tinges. The best organic amendments to increase phosphorus levels are Manure, Bonemeal, Fishmeal, Powdered Limestone (aka Rock Phosphate) or Neem Cake & other Neem Products.


  1. CALCIUM – This helps your plant build stronger cell walls, enhance its metabolism, fight heat stress, develop greater resistance, and grow better quality fruit. It is most easily accessed when soil pH is neutral or alkaline. Signs of calcium deficiency are discoloration and spotting of leaves, curling up of young leaves and shoots, burnt tips of buds and leaves, and blossom end rot in tomatoes. The best organic amendments to increase calcium levels are Bonemeal, Fishmeal, Bloodmeal, Powdered Cottonseed, Powdered Limestone (aka Rock Phosphate) Manure or Neem Cake & other Neem Products.
  2. MAGNESIUM – This increases seed germination rate, overall plant vitality and growth, and enhances production of flowers and chlorophyll. It is most easily accessed when soil pH is neutral or alkaline. Signs of magnesium deficiency are yellowing between leaf veins, marbling of leaf tissue, and premature aging of your plant. The best organic amendment to increase magnesium levels is Epsom Salts.
  3. SULPHUR – This improves plant growth and nutrition, while also improving the efficiency of other elements in your soil. Signs of sulphur deficiency are discoloration and/or purplish coloration of leaf and stem. The best organic amendment to increase sulphur levels in your soil is Epsom Salts.
  4. ZINC – This enhances plant metabolic activity. It is most easily accessed when soil pH is acidic. Signs of zinc deficiency are small, thin leaves, stunted growth and yellow discoloration of plant tissue between leaf veins. The best organic amendment to increase zinc levels in your soil is a Foliar Spray of Zinc Sulphate, Zinc Oxide, Zinc Silicate or Zinc Carbonate, to be used only when the plant is not flowering or fruiting.
  5. IRON – This helps your plant produce chlorophyll. It is most easily accessed when soil pH is acidic. Signs of iron deficiency are paleness or yellowing of leaf tissue. The best organic amendment to increase iron levels in your soil is Manure.
  6. BORON – This helps your plant develop new cells. It could be toxic to plants when administered at high doses. Signs of boron deficiency are dying of plant tips and buds. The best organic amendment to increase boron levels in your soil is Borax.
  7. MOLYBDENUM – This supports protein production in your plant. It is vital for nitrogen fixating plants like beans. High soil acidity decreases access of this element to the plant. Signs of molybdenum deficiency are irregular leaf blade formation and mottling or discoloration of leaf tissue. The best organic amendment to increase molybdenum levels in your soil is to add an alkaline amendment like Wood Ash to decrease soil acidity, or Compost, to buffer existing soil pH levels.
  8. COPPER– This helps your plant’s metabolic activity and growth. Copper deficiencies usually occur in sandy, nutrient-poor soils that are often alkaline. It is most easily accessed by the plant when soil pH is acidic. Signs of copper deficiency are stunted growth, dying back of stems and pale green, weak leaves. The best organic amendment to increase copper levels in your soil is Compost, to buffer existing soil pH levels.
  9. CHLORIDES – This helps photosynthesis in your plant. It is rarely deficient in soil. Signs of chloride deficiency are wilting or restricted root structures. The best organic amendment to increase chloride levels in your soil is to add Compost, thus giving your soil access to a variety of fresh nutrients to enhance its composition.
  10. MANGANESE – This promotes healthy growth of your plant. It tends to occur when soil pH is acidic. Signs of manganese deficiency are browning and yellowing of leaf tissue. It is best not to attempt to administer organic amendments to increase manganese levels in your soil, as excess dosages can be  highly toxic in your soil and produce.

Looking to buy any of these amendments? Do check out my Shop….



Your  plant reaches out roots as it searches for water & nutrients. Soil texture is critical, as it could either help or hinder this process. Consider the specific requirements of the plant you are growing at my Plantopedia, and then amend your soil if needed, for:

  1. AERATION – Well-granulated, light and loamy soil will allow air into your potting mix, making it easy for tender roots to reach out, while also improving microbial activity. Increase aeration in Clay or Silty Soils by amending your Potting Mix with natural minerals like Vermiculite Granules. For a finer effect in aeration, especially for germination or micro-green growing, use Vermiculite Dust.
  2. POROSITY – Some plants need highly porous soil, as stagnant moisture could cause rotting of its roots. In these circumstances, improve porosity and drainage by amending your Potting Mix with natural and renewable materials like Coco Peat.



Is soil neutral to begin with?

Soils vary in their pH levels from strongly acidic (pH value 5) to neutral (pH value 7) to strongly alkaline (pH value 9). Veggie plants and herbs will grow across this spectrum, depending on requirements of that particular plant type. Because of rainfall and regular watering, soils tend to keep leaching out elements – and thus need to be regularly replenished. Furthermore, this process, when extended over time, also tends to move all soils towards acidic states. Thus amendments to balance soil pH  levels are needed over time. Read more on soil pH levels here

Are soil amendments acidic, neutral or alkaline?

  • Compost, during its various stages of decomposition, moves from highly acidic to neutral states. Once thoroughly decomposed and integrated in your soil, it will not change pH levels but will buffer your soil, enhancing the ability of your plant to absorb elements, irrespective of the existing pH level.
  • Manure of all types – Cow, Pig, Chicken, Horse, Goat & Camel – usually has an alkaline pH value. Fresh manure is strongly alkaline, but dried and composted manure has a moderate alkalinity.
  • Neem Cake & other Neem Products will increase acidity levels.
  • Wood Ash and Powdered Limestone will increase alkalinity levels.
  • Other amendments have negligible impact on soil pH levels.

What quantities of soil amendments are needed?

Using organic soil as your base ingredient, you can add these amendments as described –

  • Vermiculite and Coco Peat should be 50% max for Germination and 25% max for General Purpose Growing. These amendments lack nutrition so balance them with good quality earth or other amendments.
  • Compost should be 25% max. This amendment generates heat – the less biodegraded the hotter it is and vice versa – so balance it with good quality earth which should cool down your mix.
  • Manure, Bone Meal, Fish Meal, Blood Meal, Powdered Cottonseed and Wood Ash should not exceed 20% all put together. These are very strong amendments and need to be thoroughly mixed with base earth and watered down after mixing. Manure, especially, is extremely heat-generating and can burn seeds and young plants. All manure should be well aged and thoroughly dried before use to reduce their alkalinity levels reduce and eliminate pathogens.
  • Neem Cake & other Neem Products should be 5% max of your Potting Mix. This amendment is extremely beneficial in terms of nutrients, potential for increasing soil acidity, and as a fungicide. However, if used in excess, it can inhibit plant growth.
  • Powdered Limestone and Epsom Salts should not exceed one teaspoonful per plant, finely sprinkled on your soil surface, or diluted and  watered into your soil (not foliage). Once again, these are strong amendments and need to be used sparingly.
  • Zinc-based Foliar Sprays and Borax should be used strictly per manufacturer’s instructions.

If you prefer to use pre-assembled organic Potting Mixes, find them at my Marketplace….

How are soil amendments added?

Most soil amendments need to be thoroughly mixed so they get integrated into your Potting Mix (as a basal dressing) giving your plant roots access to its elements. The finer the grain of the amendment, the sooner it will breakdown and the easier it will be for plant roots to access nutrients. Grinding down chunky pieces and sieving is, therefore, a good idea. Also remember, that amendments that tend to generate heat like Manure, Blood Meal, Cotton Seed & Compost should always be watered down after mixing and use in soil. With Manure, special precautions should be taken to bury the manured content within the soil (deep disking) and prevent exposure of foliage and crop to it. Direct contact of “truck-garden” crops like lettuce and tomatoes with infected manure has been linked to e-coli outbreaks.

Powdered Limestone and Epsom Salts can be sprinkled on, or watered into the soil (as a top dressing) to dissolve gradually into your Potting Mix. Do not place them in proximity to root, stem or foliage as they can burn/irritate the plant when at full-strength.

Calcium can take up to 3 years to be integrated into your soil if it is sprinkled on the top layer, though solution-grade calcium can speed up the process to 1-3 months. So a liquid solution is always better than dusting if you need a quick fix.

Foliar sprays of Zinc & Boron are to be sprayed on leaves and stems only, by dissolving the amendment in recommended quantities of water/oil.

What about other home-made soil amendments?

There is a plethora of home-made soil amendments recommended by organic farmers – from panchagavya to diluted buttermilk to asafoetida (heeng) applications. If you find that these work for you, do use them. At this stage, I would think that more research is required to conclusively co-relate elements in each of these amendments, with elements that are deficient in one’s soil. Also, the effect of residual elements of these amendments on one’s soil’s constituent and pH level still needs to be tested.


* Reference:

4 thoughts on “Soil Elements & Amendments

  1. Navneet Arora

    Dear Mandy , discovered your site while looking for epsom salt for my little kitchen garden. What a delightful find ! Just what I needed as I am an amateur gardener with no farming background/knowledge whatsoever but just a passion for health and nutrition which I hope will not let my new found interest in kitchen gardening get defeated by pest attacks on my veggies 🙂 I stay in Bhubaneswar which has tropical climate like Mumbai so your posts are godsend …just checked out ‘soil elements and amendments’. Now what I need is a post with some pics of prevalent types of pest attacks so that I can identify the problem and administer the right medicine though even the descriptions are helpful and I am going to try some of the ideas suggested by you.
    Is it not good to add lemon peels to the compost ? I remember reading this in one of your articles -it seems the good caterpillars get impacted…just wanted to recheck.
    and a happy share :)- I was struggling with my curry leaves plant for years but buttermilk has done magic though I have no idea what it has done to the ph level of the soil.
    cheers !


    1. Mandy Post author

      Thanks Navneet – glad you liked the site! Yes, more and more of us must grow our own food – and I commend you and wish you good luck on your efforts! I have started retailing hard-to-find organic soil amendments like E-salts through the major e-commerce sites like eBay and Amazon, so please go ahead and order whatever you may need….On another note, lemon peels and all other citrus fruit waste tends to raise acidity levels in the compost, thus killing off the worms that are needed for decomposition. So no lemon peels….Buttermilk would tend to enhance microbial activity in the soil (beneficial microbes). Happy farming!


  2. Mathew Nainan

    Hi,I’m from Mumbai. I wish to grow potatoes in buckets on my window sill. I have learnt that potatoes require acidic soil. Would like to know how to acidity soil to grow potatoes.



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