Plants have their mechanism to express nutrient requirements by showing "symptoms" of deficiency or toxicity (over-feeding). In a sense, this is a plant's voice or body language that can even reveal to us which mineral is deficient. Many a times, similar symptom may occur due to deficiency of more than one essential elements. In such a case, observing, if the symptom first appeared in newer leaves and shoots or the older ones, can help in identifying the true cause of deficiency. This happens because some of the elements are mobile, meaning they can move from one part of the plant to another whilst the others are immobile.

• Mobile elements: N, P, K, Cl, Mg, Mo. If the mineral element is mobile, it's deficiency/toxicity appears in the older part of the plant first. This is because the nutrients travel from older leaves to the newer leaves where they are needed most.
• Immobile elements: S, B, Fe, Zn, Ca, Cu, Mn, Ni. If the mineral element is immobile, the nutrients can not move from the older to the newer leaves. Therefore, deficiency symptoms appear in the growing region of the plant first.

Leaves & stems of Phosphorus deficient plants are generally dark green. Older leaves turn yellowish with a pink/purplish margin.

Inorganic plant nutrition is any plant nutrition additive that originates from non-living sources or does not naturally exist in the nature. Inorganic nutrients are nutrients synthesised in factories, example minerals or fertilisers.

When it comes to plants, they can absorb nutrients only in the form of ions (which are devoid of carbon and hence inorganic). So for a plant, a nutrient is a nutrient; it does not matter whether it originated from an organic source or an inorganic one. All the nutrients must first be broken down into inorganic ions before plants can absorb them. With this clarity, the question that arises is, is there then no difference between organic and inorganic nutrients. Let's try to find the answer to this query by developing an understanding of how these nutrients work.

In an Organic nutrient, the ions are bound to compounds through chemical bonds. These bonds get broken down slowly by bacteria, earthworm, and other microorganisms, ensuring a slow release of ions for the plant root to uptake. This release process happens in damp conditions and temperatures of above 50 F. Due to this mechanism, there are several distinct advantages and disadvantages of using Organic Nutrients.

• The use of Organic nutrients improves soil texture and composition due to the presence of Organic matter.
• Since nutrients get released at a slow rate, a lower amount of nutrient leeches into the ground. Overall less number of application (or lesser quantity) is required.
• The chances of burn caused by excessive nutrition are abysmally low while using Organic Nutrients.

• Since nutrients are released slowly, plants may get less amount than they need and take longer to grow.
• It is difficult to pinpoint exact nutrient composition (available for plant intake) in the organic nutrients. Thus some specific nutrient deficiencies may occur in plants fed solely on Organic Nutrients.
• Organic nutrients usually cost more than their inorganic counterparts.
• At lower temperatures, the efficacy of nutrients may decrease significantly. This phenomenon happens because the process of ion release from Organic nutrients needs higher temperatures.

In inorganic nutrients, ions are released rapidly (there are now some slow-release inorganic nutrients as well) and become available for plants to uptake irrespective of temperature and humidity levels.

• The ions are precisely measurable and available for uptake readily. Thus the results are quick and effective.
• Inorganic nutrients cost lower than their organic counterparts.

• Since the ions are released fast, many applications may be required at regular intervals.
• A lot of nutrients can get leached into the groundwater through the soil, thus having an adverse environmental impact (when used in ground-based farmland at commercial scale).
• A higher dose of inorganic nutrients may lead to an excess of nutrients, thus leading to leaf burn in plants.

Historically, Micronutrients have not been given the due importance they deserve. This has led to a severe deficiency in soils around the world. Estimates suggest that 30% of all the cultivable land the world over is deficient in Iron. 51% of the area under cereal cultivation is deficient in Zinc.

If you are into any form of gardening or farming activity, we hope you do give due importance to Micronutrient balance in your plants. This will do wonders for your plants. CityGreens has a variant called Nutes, which is a balanced blend of many essential Micronutrients. You can use it in both soil-based and soilless growing media. You should give it a try, especially if you are growing in organic matter, as organic compounds bind with most of these micronutrients, reducing their availability for the plants. Ensure that your plants get complete nutrition. Enjoy a healthy yield.

Happy Growing!

Hardly any plant can survive without photosynthesis. The molecule that helps plants carry out the process of photosynthesis is ‘Chlorophyll.’ Magnesium is a major constituent of chlorophyll. Thus, for any plant to convert light energy into food, they need Magnesium. Lack of Magnesium will mean that a plant will not be able to meet its energy requirements and growth will be sub-optimal.

This is because the terms NPK do not denote the amount of Nitrogen, Phosphorus, and Potassium but the amount of Nitrogen, Phosphorus pentoxide (P2O5), and Potassium oxide (K2O) in the mix. Thus, NPK 10-10-10 consists of 10% Nitrogen, 10% Phosphorus pentoxide, and 10% Potassium oxide, remaining 70% being filler or inert matter.

For the sake of understanding, we will consider NPK 10-10-10. As explained above, NPK 10-10-10 consists of :

• Nitrogen - 10%
• P2O5 - 10%
• K2O - 10%

each molecule of P2O5 consists of two atoms of P and five atoms of O. In elementary chemistry classes, we learned that the atomic weight of P is 31 and of O is 16. Thus a molecule of P2O5 will weigh 142 (=31x2 + 16x5) of which 62 is contributed by P (=31x2). Thus the amount of P in P2O5 is 43.6% (=62/142).

Similar calculations for K2O will show that the amount of K (atomic weight 30) in K2O is 83%.

So, in terms of macronutrients, NPK 10-10-10 consists of

• Nitrogen - 10%
• Phosphorus - 4.36%
• Potassium - 8.3%

Having understood this, we can now answer the queries that were posed above

• Which one is better NPK 05-05-05 or NPK 10-10-10?
• None. They both are same. It's just that the former has half the strength of the latter.
• Are both balanced?
• Depends, if you are looking for a balance in N, P2O5, and K2O, then they both are balanced. However, if you are looking for a balance in N, P, and K, then, none of them are balanced.

CityGreens NPK differs on a couple of counts

• Along, with NPK, it has many other vital micronutrients
• When used as instructed, it results in a ratio that provides an almost equal amount of N, P, and K to the plants (instead of an equal amount of N, P2O5, and K2O)

Having said that, just to reinforce, as we had pointed out in our last week's post, there is no perfect nutrient formula that can work wonders with all the plants and in all the situations. What your plant needs may be entirely different from what your neighbours' may need. You will need to experiment to arrive at the best solution for your specific case. We hope you do that.

Happy Growing!

Nitrogen aids in the process of photosynthesis. A lack of nitrogen will lead to chlorosis (a discolouring of leaves) and stunted growth. An adequate amount of nitrogen promotes healthy leaf growth and results in imparting a bright green colour to the leaves.

Phosphorus is necessary for energy transfer and consumption in various parts of plants. Phosphorus helps in promoting root growth, blooming, seed production and improving crop yield.

Potassium can be considered equivalent to a CPU (Central Processing Unit) of a plant. It regulates most of the vital functions within a plant, including internal moisture, water balance, and low-light photosynthesis. Potassium has a high impact on the end-quality of the fruit, including its shape, size, colour, and taste.

Plants draw these nutrients from the growing medium, which is the soil in a majority of the cases. Soil, as such, does not have any nutrients of its own. It, however, acts as a storehouse of nutrients that gets added to it naturally through the atmosphere, weathering of rocks, bacterial conversion, decomposed animal waste etc. or artificially by adding fertilizer, manure, and compost etc.

Yes, you can, if you are growing in fertile soil which may have some stored nutrients. But, once the stored nutrients run out, the plant will begin to grow weak, will be unable to withstand pests, and yield will decrease or become non-existent (plant will focus all its energy on surviving and not on growing as humans will do in case of famine). Thus whether one is growing in soil or outside soil, external nutrition must be provided to plants to ensure a healthy garden/farm. More so, in case of growing in a soil-less medium like Cocopeat, hydrotons, rice husk or water.

For adding these nutrients externally, one can either depend upon Organic sources like bacteria, earthworms, fish excreta, vermicompost, manure etc. or on inorganic ones like fertilizers and precision blends. Again, taking the analogy of humans, one can either provide nutrition through organic means like milk, rice, etc or through inorganic supplements like baby food, Farex, Cerelac, Horlicks, Bournvita etc. or take the best of both worlds, adding a spoon of Horlicks to that milk. Which one to use? It is more a matter of individual preference; some prefer only organic; some prefer precisely measured scientific blends depending upon specific plant needs; some prefer using a mix of both. All of these should work with the plants.

Happy Growing!