Your plant requires 17 nutrients to complete a happy life cycle. For various underlying reasons your plant may experience issues with nutrients. Nutrient issues can manifest because the nutrient is lacking in the medium provided. It can also be as a result of your plant not being able to up take or avail itself of that particular nutrient in the medium. This means the nutrient is available in the medium, but your plant can’t access it. It can also be as a result of your plant not being able to deploy that nutrient to where it needs to go.

Undoubtedly the most important factor determining happy plants is good quality soil. Quality soil will have a good balance of nutrients at your plants root tips. Factors which determine good quality soil:

• Loamy soil with good organic matter.
• Good microbial activity.
• Light, aerated soil with good drainage.

There are other factors which will determine plant health in terms of nutrient availability:

• Moisture control.
• Soil pH that ranges 5.8-7.2. Please take time to read this to understand soil pH and nutrient availability.
• Soil temperature.

Poor quality soils are pretty much the opposite and will most certainly create the ideal environment for nutrient issues. Here are some of the factors to to look out for and avoid:

• Clay based or sandy soil with very little organic matter.
• Compacted or dense soils with poor aeration and drainage properties.
• Over farmed or over irrigated soils leached of nutrients.
• Water logged or dry soil.
• Extremely acidic or alkaline soils (below 5.8 pH or above 7.2 pH).
• Cold soil temperatures – outside of growing season.
• High Sodium soils.

Getting this right will already set the course for 80% of your plants happy and healthy life cycle.

Get your soil tested
If you are in the business of growing chillies, get your soil tested by a laboratory to establish the quality of your soil and any deficiencies or toxicities that may exist. This will give you the best data on the condition of your soil, what your soil is lacking and how to amend your soil (what and how much). If you are using ground water, get this tested too to establish any issues that can affect your grow.

This section is for home growers who can not substantiate getting soil tested and need to use a more hands on approach of observation to pinpointing the issue. In our experience pinpointing nutrient issues in plants can be tricky. Symptoms of nutrient imbalances can manifest as singular or multiple symptoms. Symptoms of deficiencies can also be (and very often are) as a result of nutrient toxicities which can manifest as a nutrient toxicity or the deficiency of other nutrients.

Some diseases and insect damage can manifest with symptoms which can very easily be misdiagnosed as a nutrient imbalance – and vice versa! The symptoms of herbicidal damage are also difficult to pinpoint and symptoms can very easily be misdiagnosed as an underlying nutrient issue.

As a first port of call we need to establish that the issue at hand is indeed a nutrient imbalance. For this we need to asses the primary data. Other factors which might be the cause of the plants symptoms can be insects and disease, so we need to rule these two factors out.

Primary Data
Examine the visible signs that can help you identify the possible underlying issue(s). Check your plant thoroughly. Be critical to establish the symptoms and exactly where on the plant these symptoms are appearing. Is this an isolated plant issue or are the same symptoms affecting multiple plants? Asses the primary data.

Rule out insects

• Insects
  Check you plant thoroughly for insects activity. Aphids, Whitefly, Mealybugs, Mites, Thrips. The symptoms of insect damage can also look like nutrient issues.
• Disease
  The presence of insects (or insects having previously been around) can also be a good indicator for disease. Are there insects? Were there insects previously? If yes, look for signs of infection on foliage, stems or fruit. Necrotic, dark spots with yellow halos? Light or dark coloured molds? Rotten or soft fruit?

When did the symptoms first appear & do they co-inside with any changes in your plants routine?
Once insects and disease are ruled out, there is a very good possibility that the symptoms are as a result of nutrient issues. Often symptoms will coincide with a change in your plants routine. It is good to be cognitive of any changes in your plants routine that took place at the same time or within a week of symptoms first appearing. If this is the case, there is a very good chance that this change in routine is the underlying cause. Changes in routine may include:

• Feeding/Nutrient
  Have you started feeding fertilizers/supplements? Have you changed your feeding schedule? Have you changed product/brand?
• Watering
  Have you changed the amount of water you have given the plant recently? Has there been a lapse of watering?
• Environment
  Has the weather changed recently? Has the plant been moved/transplanted? What about the quality of your soil? Has the plant been subjected to light changes, temperature, weather changes?
• Pesticides/Fungicides
  Many pesticides and fungicides contain nutrients – for instance Copper and Sulphur. Be cognitive of whether you have used any of these regularly. Always stick to the recommended doses. Over usage of pesticides or fungicides can create a build up of excess nutrients (copper or sulphur) and ultimately create a nutrient toxicity!

If there is sufficient evidence to support a change in any of the above, there may very well be an issue with your soils nutrients or your plants ability to avail itself of the nutrients in the soil. This may be due to a nutrient lock out/nutrient deficiency or toxicity (too much of a nutrient).

In our experience, nutrient issues are mostly as a result of growers over feeding their plants. Over feeding with nutrients (excess nutrients) can very easily result in toxic symptoms. These often manifest as nutrient deficiencies as excess in one nutrient can block other nutrients. So if you are feeding your plant fertilisers, you also need to be cognitive that these symptoms may not just be as a result of a nutrient deficiency, but can in fact be a nutrient toxicity manifesting as other nutrient deficiencies.

You will know if you are feeding your plants if toxicity is feasible. Unfortunately many growers do not heed instructions on fertilizers and have a tendency to over feed. Could this be the case with you? Also, if you have previously used fungicides or pesticides, these too can bring about copper or sulphur issues. Be cognitive of the use of such agents and always follow the instructions.

Avoid trying to diagnosed in winter time, early spring or autumn
Avoid trying to diagnose a plants nutrient issue in winter, early spring or autumn (out of grow season). Dormant plants will show all sorts of ailments. Lower temperatures in the soil mess with the plants ability take up nutrients. These signs are not a true reflection of a plants nutrient issues and are usually remedied once soil temperatures increase.

Detective work – the game is a foot...

When you are sure that the issue at hand is a nutrient issue. There are a few key questions that will help you diagnose and narrow down the culprit(s).

• What part of the plant is affected?
  • Top Foliage – New Growth?
  • Lower Foliage – Old Growth?
  • Both New and Old Growth?
• Are the leaves deformed at all?
  • Wrinkled or bubbling?
  • Small & Stunted?
• Are the leaves showing damage?
  • Necrosis, dead areas on leaf?
    • On leaf outer?
    • On leaf inner?
• Are there signs of discolouration?
  • What colour do you observe?
    • Is the colour even over the leaf?
    • Is the colour mottled/blotchy?
    • Is the colour between the leave’s veins (interveinal) – where is the colour located?

These questions should always be asked when diagnosing the symptoms. By referencing the answers with the information below. You will be able to formulate a crime scene and ultimately pinpoint the culprit(s). Which in turn will give you the background of reasons why these deficiencies are occuring in the first place. Which will give you the opportunity to fix the underlying issues.

Nutrient Mobility (Read)

Plants need to be able to deploy nutrients throughout their system - from the roots tips to the very outer growth points of the plant. But, there are some nutrients that plants may struggle to deploy to where they need to go. This is often referred to as the "mobility" of nutrients. Some nutrients are said to be less mobile than others.

Your macro-nutrients – Nitrogen, Phosphorus, Potassium all have good mobility. Magnesium & Chlorine also have good mobility in plants. But most of the Micro-nutrients unfortunately have poor mobility in plants. Of these, Calcium is a commonly occurring culprit as your plant needs calcium to sustain growth.

The diagram below illustrates how deficiency symptoms for mobile nutrients generally affect the old growth (older leaves) of capsicum and less mobile nutrient deficiencies generally manifest in the new growth (younger leaves) of capsicum plants. this will tie in with the line of questioning above.

Soil pH & Moisture
Other than soil quality, soil pH and moisture are very instrumental in determining the availability of nutrients. Watering should be consistent. Extremely wet or dry, extreme acidic and alkaline soils will result in nutrient issues. So it is always a good idear to check your soil moisture and pH when trying to analyze the nutrient issues at hand. While soil pH can naturally be extremely alkaline or acidic, if your soil is known to be alkaline and has dramatically changed pH, it is always a good idea to be cognative of any recent soil amendments you have done. Lime, sulphur and other soil additives (or pesticides/fungacides) can easily alter the pH of your soil. Also, if you are using municipal or borehole water – test the pH if your soil pH is out of whack. These can all be reasons for your soil pH drifting and this may be why you are experiencing nutrient issues.

The complexity of trying to capture an illustrated guide to nutrient imbalances in chillies is that no two cultivars and growing conditions are ever the same. Symptoms can vary depending on growing conditions, the plants tolerance (every cultivar is different) and the complexity of the nutrient imbalance itself (there may be more than one nutrient deficiency or even a toxicity). As such, it is very difficult to show a picture perfect text book example of a given nutrient deficiency or toxicity. There can be quite a large degree of variance in the symptoms. But with a little bit of detective work and observation, we can roughly get an idea of what nutrient issues your plant is having and what the course of action should be.

Please use this article as a guideline. For conclusive results it is always best to get your soil tested. Tests are accurate and conclusive.

Nitrogen (14.01)

Nitrogen is one of the primary macro-nutrients essential for plant growth. Nitrogen is very mobile in plants. Nitrogen is needed to make DNA, proteins and chlorophyll. Nitrogen is readily available in the soil and is reliant on rich, organic soils that have a good microbial base and lots of organic matter available for breaking down. Nitrogen promotes good roots and shoots as well as quality fruit and fruit set.

Factors affecting Nitrogen availability

• Alkaline (above pH8) and Acidic (below 6) soils result in low Nitrogen availability.
• Poor quality sandy soil low in Organic matter.
• Very wet soils. Lots of water (high rainfall or over watering) will flush Nitrogen away from root zones.
• Dry soil.
• Presence of Nitrogen fixing legumes.

Nitrogen Deficiency

The most common cause of Nitrogen deficiency is water. Excessive watering and heavy rains can wash/flush Nitrogen out of the root zone. Poor, over farmed soil may be nitrogen deficient - especially soils that have previously been planted with Nitrogen hungry crops.

Symptoms
Nitrogen deficiency manifests in stunted/slow growth. Reduced yield and quality of fruit. Chlorosis of older leaves, which if left untreated, will wilt and die off.

Treatment
Nitrogen is optimally available between 6 - 8 pH. So check your soil pH and adjust to bring the pH within these parameters if too alkaline or too acidic. Ensure your plant is getting sufficient water. Over watering and excessively dry soils must be avoided.

If pH and watering are in check, another reason could be down to poor soil quality. Nitrogen requires rich loamy soils with lots of organic matter that organisms can break down. In this instance, mulching and the addition of compost and green organic matter will benefit in the long run. Nitrogen supplementing with a liquid supplement high in Nitrogen is a good way to kick start this.

A soil test may be required to establish if the soil has a nitrogen deficiency. If the soil deficiency is not just Nitrogen, it may be best to go for a broad spectrum supplement that has a high concentration of Nitrogen as well as a broad spectrum of other nutrients. This will ensure that other nutrients will be replenished also. But, if the test shows a nitrogen only deficiency, you may wish to consider a synthetic or other fertilizer that is specifically high in Nitrogen. This would be to avoid effecting other nutrients. Chicken manure, fish emulsion & sea kelp emulsions are high in Nitrogen. Also, blood meal, urea, ammonium or any nitrate based fertilizer.

Nitrogen Toxicity
The most common cause of Nitrogen toxicity is over fertilizing. Symptoms will manifest themselves as having taken up too much Nitrogen or Ammonium.

Symptoms
Nitrogen toxicity will result in (bolting) tall and lanky plants with very deep green foliage. Chances are that as plants bolt due to the nitrogen, plants may also experience Calcium deficiency as the plants is not able to keep up with Calcium supply. Nitrogen heavy plants will also be magnets for insect infestations and ultimately disease. Plants with Nitrogen toxicity will also struggle with flower drop.

Plants may also show signs of Ammonium toxicity. Brown roots and dying back of root tips (visibly stunted roots). Which in turn will result in stunted plants. Black spots on stems and leaves. New foliage may be yellowing and stunted.

Treatment
As a first port of call, ease off the Nitrogen. If you are using a Nitrogen rich fertilizer, stop. Add brown organic matter (leaves, straw) and work it into the soil at the base of the plant. Organisms in the matter will help burn up nitrogen. Also, it is a good idea to increase regular watering (a little) to help flush the excess nitrogen from the root zone. Remember, a little! We don't want to end up with soggy roots and root rot as a result of fungal infections at the root zone. If your nitrogen toxicity caused your plant to drop lots of flowers, you can supplement with Potassium (Kelp or Seaweed solution is good for this).

Phosphorus (30.97)(-)

Phosphorus is one of the primary macro nutrients essential for plant growth. Phosphorus is very mobile in plants. Phosphorus is needed for plant cell division (growth), photosynthesis and respiration. Phosphorus is necessary for fruit and seed production and plays an important part in enzymes, protein and DNA. Phosphorus happy plants have great roots, flower and fruit production. Phosphorus is also key in a plants ability to uptake water. Phosphorus is essential for early fruit set. Plants deficient in Phosphorus very often take a long time to mature. Phosphorus is a very important nutrient that plays many rolls in the plants health.

Factors affecting Phosphorus availability

• Alkaline (above pH7.5) and Acidic (below 6.5) soils result in Phosphorus binding with other nutrients (calcium & aluminum) and being less available.
• Poor quality soil. Dense compacted soils with poor aeration and low in Organic matter.
• Water stressed soils with too little or too much water.
• Cold soil.
• Iron rich soils.

Phosphorus deficiency

The most common cause of Phosphorus deficiency is poor quality soil. Compacted soils with poor aeration and low organic matter. These soils also tend to be more prone to water issues. Phosphorus is also very much a seasonal issue that is more prevalent in early spring and late autumn when soil temperatures drop.

Symptoms

Symptoms manifest on the older leaves. Interveinal chlorosis and a reddish to purple blush on the leaves are the obvious signs. This is followed by necrotic interveinal spots. Leaf tips can appear burnt. On badly affected plants, older leaves will drop off prematurely. Plant growth, flowering and fruit are severely stunted.

Treatment

Ensure your soil is between 6.8-7.2pH. Compacted soils should be loosened with a fork and organic matter introduced to the soil to facilitate better aeration and water management. If your symptoms manifest early spring and late autumn when temperatures are falling, use ground cover and mulches to help raise soil temperature. Regulate your watering to ensure soils are optimally moist. If the soil is low in Phosphorus and a soil test has established this, adding organic matter, manure, bone meal, rock dust or a phosphorus rich supplement (superphosphate) will help raise Phosphorus in the soil.

Phosphorus Toxicity
Excess Phosphorus is of little concern for plants although in extreme cases it can inhibit the uptake of zinc and iron.

Symptoms
Symptoms are those consistent with zinc and iron deficiency. Symptoms can include deformed (twisted), stunted, narrowed older as well as young leaves. Interveinal chlorosis on young leaves. Delayed and slow maturing of fruit.

Treatment
Cut out fertilizers with Phosphorus and water soil to help flush phosphorus out of the root zone.

Potassium (39.10)(+)

Potassium is one of the primary macro nutrients essential for plant growth. Potassium is very mobile in plants. Potassium is important for the plants ability to photosynthesize and the conversion, transportation as well as storage of food/energy for the plant. Potassium plays an important role in conjunction with other nutrients (Calcium & Boron) in the formation of plant cells. It also helps the plant manage Nitrogen. Furthermore, Potassium has an integral part in the plants immune system – it’s ability to fight and repair damage from diseases, insects as well as colder weather and drought (water stress).

Factors affecting Potassium availability

• Dry soils prevent uptake of Potassium.
• High Rainfall or over irrigated soils.
• Dense Clay soil.
• Acidic soils (below 6.5pH) can cause Potassium lockout.
• High levels of other Cations.
• High levels of Sodium in the soil.

Potassium deficiency

Potassium deficiency is most likely to occur with plants grown in poor quality toils. Soils that are too acidic, too dry or too wet. Compacted dense clay soils with poor drainage and aeration can be the main culprits. Nutrient imbalances brought about by uncontrolled feeding can inhibit Potassium availability. Cold soil temperatures early spring and late autumn can impede the uptake of Potassium.

Symptoms

Older leaves show signs of interveinal as well as marginal chlorosis. This will progress to necrotic spots interveinal as well as marginal necrosis. The leaf may display a rash of white spots on the leaf surface. This will progress to a total scorching of the leaf. Potassium deficient plants have a tendency to be stunted in size and are more prone to disease and slow to recuperate from water stress as well as insect damage.

Treatment
First check your soil pH is correct (6.5-7.5pH). Adjust soil pH if needed. Ensure soil is not waterlogged or dry – ensure watering is consistent. Ensure soil is loamy with a good dose of organic matter. Compacted clay soils will need forking and amending with organic matter. Early season or late season Potassium issues can be due to soil temperatures being too low. Insulate soil – mulch and black plastic sheeting can help insulate as well as raise soil temperatures. If you are supplementing with soluble nutrients, make sure there isn’t a build up of sodium in the soil. This can be sorted with regular watering to leach out salts in the root zone. Also, check that other nutrients are not in excess. A balanced supplement is key. Failing all these checks, if your soil is still low in Potassium, a Potassium specific supplement can be considered (ie Banana peels, Kelp, Rock dust, Potash, Potassium Nitrate). Our advice would be get the soil tested if possible to establish your soil deficiencies or toxicities.

Potassium Toxicity
Potassium does not manifest any toxic symptoms. But, too much Potassium will cause deficiencies with other nutrients (calcium, nitrogen and magnesium).

Calcium (40.08)(+)

Calcium is a secondary plant macro-nutrient that is essential for healthy plants. Calcium has bad mobility in plants. Plants require Calcium to build cells. Roots, leaves, stems and fruit require Calcium to grow. Calcium is also needed by plants to fight attacks from pests and disease. It facilitates Nitrogen uptake and is required by plant enzymes.

Factors affecting Calcium availability

• pH - Calcium is less available in acidic soil and more available in alkaline soil.
• Organic matter - higher concentrations of organic matter hold more Calcium as a result of a higher cation exchange.
• High levels of soluble salts due to over fertilization can prevent the uptake of Calcium.
• High Nitrogen fertlisation (plants bolting).
• Inadequate water in the soil can prevent the uptake of Calcium.
• Root damage or poorly developed roots (root rot or nematodes).
• Cold temperatures can prevent the uptake of Calcium.

Calcium deficiency

Plants are predisposed to Calcium deficiencies when grown in acidic soils and or during the colder parts of the season (autumn/spring). While most soils will have sufficient Calcium to sustain plant growth, some soils are naturally deficient in Calcium. To establish whether your soil is deficient in Calcium, a soil test can be taken to establish Calcium levels in the soil. Periods of drought or irregular poor watering can resulting in inadequate water availability to the plant which in turn can bring about Calcium deficiency. Damaged roots due to disease or nematodes can result in plants not being able to take up Calcium. High levels of soluble salts in the soil due to over fertilization can also bring about a situation whereby plants are not able to uptake Calcium. Another often overlooked factor is excessive Nitrogen fertilisation. High Nitrogen can bring about growth spurts in plants which create a situation where plants are growing faster than Calcium can be deployed to the growth points. This will result in growth points being deficient in Calcium.

Symptoms

The first tell-tale symptoms that appear is in the new leaves at the growth points. Leaves at growth points appear bubbly, irregular and deformed. Plants suffering from Calcium deficiency tend to stunt. As the deficiency progresses, necrosis will develop on leaf edges and new shoots will die off at growth points.

Untreated Calcium deficiency in chilli plants will result in Blossom End Rot (BER) and/or Stip. BER is unlikely as a result of a Calcium deficiency in the soil, but most likely due to a plants inability to avail itself of the Calcium in the soil. The most common reason for Calcium deficiency being inadequate/erratic watering, due to drought or bad water management (poorly set up irrigation). Root damage due to disease and nematodes can be another factor for a plants inability to uptake Calcium. Another common underlying issue is as a result of high concentrations of soluble sodium in the soil due to over fertilization.

Treatment

Ensure soil pH is within the acceptable range to facilitate Calcium availability (6.5 - 9.5). Adjust soil pH by raising or lowering soil acidity to bring soil into this pH range.

Avoid periods of water shortage with supplemented watering. Avoid over watering and periods of drought.

Cut out supplementing with fertilisers high in Nitrogen.

Mulching can assist with retaining soil moisture as well as insulating soil temperature during colder parts of the season.

Calcium Toxicity

Calcium does not manifest symptoms of toxicity in plants. It can however cause deficiencies in other nutrients (commonly Magnesium, Potassium and Boron) by blocking their uptake. In this event cease supplementing Calcium and supplement with the deficient nutrient(s).

Magnesium (24.31)(+)

Magnesium is a secondary macro-nutrient in plants. Magnesium has good mobility in plants. It is an integral part of the make up of chlorophyll and is vital for photosynthesis in plants. It is is key to the plants ability to take up other nutrients and assist in the mobility of those nutrients throughout the plant (phosphorus) and assist the plant’s ability to use iron.

Factors affecting Magnesium availability

• Acidic Soils (below 6.5 pH).
• Good organic soils with a high CEC (Cation Exchange Capacity) are key to good Magnesium availability.
• High concentrations of Manganese &/or Potassium can lock out Magnesium.
• Low soil temperatures.

Magnesium deficiency

Magnesium deficiencies often present early spring and late autumn when soil temperatures are too cold or in instances where the soil is very acidic (below 6.5 pH). Poor quality soil with little organic content and high soil sodium can impact availability of magnesium.

Symptoms

Magnesium deficiency manifests as interveinal chlorosis on older leaves. This will develop to interveinal and marginal necrosis on leaf edges.

Treatment

Symptoms early season may be short-lived as temperatures rise. Mulching and black sheeting on the ground can help insulate and raise soil temperature. If symptoms manifest during the growing season, check soil pH (anywhere 6.8-7.2). Amending poor quality soil with good organic material and working this into the soil will help in the long run with magnesium availability. If you are using fertilisers, use a fertiliser low in potassium and manganese. Drip irrigation can help flush high concentrations of sodium from the root zone.

For a quick turn around Epsom Salt (Magnesium Sulphate) is a great choice as it is immediately available to plants both as a drench and as a foliar spray. But, Epsom Salt is NOT a miracle cure for everything (despite what the internet may tell you) and while it will very quickly fix any signs of chlorosis in the leaves – it will not fix the underlying issue. This will not go away. You will still need to address the underlying reason why the Magnesium deficiency is present in the first place. Acidic soil can be amended with Dolomitic Lime to raise soil pH and also give added Magnesium as Dolomitic Lime is high in Magensium.

Magnesium Toxicity

Magnesium toxicity is unlikely. Magnesium toxicity will bring about deficiencies in Calcium and Potassium. Establish the source of the excess Magnesium and address this. Flush out any excess magnesium in the soil with regular watering.

Sulphur (32.07)(-)

Sulphur is a secondary macro-nutrient in plants. Sulphur has ok mobility in plants. It’s key functions are in the production of chlorophyll as well as the production of amino acids, enzymes and proteins in plants. It also facilitates the function of Nitrogen in proteins.

Factors affecting Sulphur availability

• Acidic Soil.
• Poor quality soil (low organic matter).
• Nitrogen depleted soils.
• Poor quality soil – compacted and/or water logged.
• Cold soil temperature.
• Industrial pollution as well as high levels of Sulphur in water may contribute to Sulphur toxicity in plants.
• Ammonium can improve the uptake of Sulphur.

Sulphur deficiency

Cold and poor quality soils low in organic matter. Also compacted or water logged soil are the usual underlying culprits with Sulphur deficiency.

Symptoms

Sulphur deficiency manifests in the younger leaves as a very distinct overall yellowing of the young leaves. This progresses to very contrasty defined dark brown necrotic spots on the leaf edges. Plants with Sulphur deficiency are stunted in appearance and leaves can display a cupping (leaves rolling over at the edges). Plants affected will have reduced yields.

Treatment

Sulphur deficiency early spring may be short lived as soil temperatures rise. Mulching and black sheeting can help insulate as well as raise soil temperature. Poor quality soil needs to be addressed – loosen soil (aerate compacted water logged soils). Work organic matter into the soil. Ensure soil acidity is higher than 5.8 pH.

With Sulphur issues, it is always a good idea to get your soil tested (if this is an option) as Sulphur deficiencies tend to be very intricate. Adding Sulphur fertilisers to the soil can lower the pH of soils – which may cause other issues. Suppliments containing Sulphur can cause issues with other nutrients. Low levels of Nitrogen can be a factor in Sulphur deficiency. But deficiency can also be due to Phosphorus and Potassium. One has to be very selective with the form of Sulphur added to the soil, to ensure it will not create an imbalance with the other nutrients. Ammonium Sulphate, Potassium Sulphate and Super Phosphate are common remedies for Sulphur deficient soils.

Sulphur Toxicity

Sulphur toxicity is very unlikely. But, as previously stated, Sulphur fertilizers incorrectly used can bring about issues with other nutrients – Nitrogen, Potassium & Phosphorus. Excess Sulphur can be flushed from the root zone with regular watering. Cut out the source of Sulphur.

You may also want to be cognative that many insecticides and fungicides contain Sulphur.

Boron (10.81)(+)

Boron is a micro-nutrient in plants. Boron is believed to have bad mobility in chilli plants. Boron is key in cell division and the healthy growth of your plant. Boron is mostly required at the growth points of the plant. It is essential for the production of flowers, fruit and seeds. Boron issues can directly affect productivity and yield as well as quality of fruit.

Factors affecting Boron availability

• Cold Soil Temperature.
• Water stressed soil. Water logged or excessively dry soil.
• Poor quality soil, compacted, low in organic matter.
• Alkaline Soil (higher than 7.2pH).
• Soil high in Nitrogen and/or Calcium.

Boron deficiency

Areas of high rainfall or situations where watering is excessive, Boron can be leached from the root zone. Poor quality soil can also be one of the main underlying reasons for Boron deficiencies.

Symptoms

Boron deficiency manifests as stunted plants with stunted compacted growth points. Cupped (downward curling) leaves. Mottled chlorosis over the leaf. Flowers shrivel up and look burnt. Leaf veins go orange. Any fruit that does set can manifest corking and cracks. Plants with Boron deficiency can result in poor seed production.

Treatment

Quality soil with good organic matter is key. Soil pH should be between 5.8-7.2. Regulate soil moisture ensuring that watering is consistent and not excessive or too little. Soil tests that reveal low levels of Nitrogen can be amended to improve nitrogen levels in the soil. Excess Calcium levels in the soil should also be addressed by cutting down on the source of excess Calcium. Soils known to be deficient in Boron can be addressed with foliar treatments with Borax or Boric Acid.

Boron Toxicity

Soils can be naturally high in Boron in coastal areas and borehole water can also be high in Boron. Industrial as well as mining affected areas can also show high levels of Boron.

Boron toxicity will manifest as chlorosis on the outer edge of leaves that progress inward towards the centre of the leaf. Black necrotic spots between the veins in extreme cases.

Treatment

In alkaline soils, amend soil to reduce pH closer to 7. A soil test (if doable) will establish levels of Calcium and will determine if adding calcium to the soil is an option (if soil has low levels of Calcium). Calcium can help reduce the uptake of Boron. Testing borehole water may also establish the possible source of the excess Boron, in which case cutting out the borehole water as a source for the watering will also tackle the Boron issue. If the excess Boron is due to pollution or mining activity in the area, treatment can be very complicated. It may be advisable to find another area of the garden to grow your chillies.

Manganese (54.94)(+)

Manganese is a micro-nutrient in plants. Manganese has poor mobility in plants. Manganese plays a very important role in the Photosynthesis of plants. It is key in the production of Chlorophyll. It controls the absorption of Nitrogen and plays an important role in the production of Ascorbic Acid, Carotene and Riboflavin. As such, Manganese is important for healthy growth and pathogen resistance in plants.

Factors affecting Manganese availability

• Manganese less available in Alkaline Soils (above 7.5 pH)
• Acidic Soil may create excess Manganese (below 5.5 pH)
• Cold soil temperature.
• Irregular moisture levels in soil.
• Heavily organic soils – Manganese less available.
• Excessive Iron, Low Nitrogen – inhibits Manganese uptake.
• High concentrations of Nitrates, Sulfates and Phosphate (anions) can increase manganese uptake.

Manganese deficiency

There are quite a few factors that can induce Manganese deficiency in plants. The most common factor is alkaline soil pH and poor soil quality. Cold soil temperature as well as irratic watering can induce Manganese issues in plants.

Symptoms

Manganese deficiency manifest mainly in young leaves. Young leaves show interveinal clorosis. All veins on the leaf appear dark green. Young leaf formation can be small and irregular. This gives the leaf a mottled appearance – like a giraffe patterning. Necrotic spots will appear along the main veins on the leaf.

Treatment

This is an instance where a soil test will really help establish the issue and the course of action to be taken. As a first course of action ensure soil pH is within the 5.8 – 7.2 range. Overly alkaline soil will be a big culprit in Manganese deficiency. If the soil is alkaline, amend soil with an acidifying agent (Sulphur). This will help with Manganese availability.

Early spring soil temperature can be addressed with mulching and black sheeting to insulate as well as increase soil temperature. But this will be short lived once temperatures pick up.

Soil low in Nitrogen can be amended with Nitrogen rich fertilisers which in turn will improve the uptake of Manganese. Look for a fertiliser high in Nitrogen that also contains phosphate and sulphur – which will be even better. You can also improve soil nitrogen by planting Nitrogen fixing legumes.

Manganese Toxicity

Manganese Toxicity mostly occurs in acidic soils. Manganese toxicity will manifest as irregular distorted leaves with dark necrotic specks and necrotic lesions that spread from the leaf edge inwards. Manganese Toxicity can also induce symptoms of iron deficiency. Resulting in a yellowing of young leaves.

Treatment

Amend acidic soil to raise pH closer to neutral (7 pH) will reduce excess Manganese uptake. Ensure soil has sufficient organic matter. The more organic, the less Manganese availability. Low Nitrogen, no Manganese fertilisers are recommended to reduce excess Manganese. Adding silicon can also help reduce uptake of Manganese.