Manganese deficiency in tomato plants

Manganese is important for allowing plants to harness the energy of the sun (photosynthesis). Soil shortages are rare, but manganese can be unavailable to plant roots in alkaline conditions. Ericaceous (acid-loving) plants are particularly vulnerable when growing in alkaline soils or potting composts.

Tomatoes are very susceptible to manganese deficiency. Interveinal areas develop yellowish gold spots giving the leaf a speckled appearance. All veins, including the very small ones, and a small frame around the veins, remain green. Petioles and the stems can develop similar Symptoms. Few flowers or fruit will develop if the deficiency is severe.

Role of manganese in tomato plants

Manganese is required for chlorophyll formation and oxide-reduction reactions in cells. It is also involved in the synthesis of ascorbic acid (Vitamin C).

Establishment - Ensure good shoot growth
Vegetative Growth - Ensure growth is not limiting

While considered a micronutrient, manganese is essential to the growth and vitality of African Violets. It plays an important role in the function of photosynthesis, thus contributing to those processes which give African Violets their deep, green leaves.

Cause of manganese deficiency

The most common cause of Manganese Deficiency is either a lack of available manganese in the soil or a pH imbalance in the soil which is inhibiting the absorption of manganese and other nutrients. However, it may also be caused by an excess of potassium or phosphorus.

Symptoms

The leaves show a light interveinal chlorosis developed under a limited supply of Mn. The early stages of the chlorosis induced by manganese deficiency are somewhat similar to iron deficiency. They begin with a light chlorosis of the young leaves and netted veins of the mature leaves especially when they are viewed through transmitted light. As the stress increases, the leaves take on a gray metallic sheen and develop dark freckled and necrotic areas along the veins. A purplish luster may also develop on the upper surface of the leaves.

While rarely seen, transient deficiencies can occur during wet seasons or in sandy or peaty soils of a high pH. Manganese is not very mobile in the plant and deficiencies are best prevented by using foliar sprays. Temporary Mn deficiency is known as ‘growth mottle’ and is seen during flushes of rapid plant growth.

Prevention and control

Prevention can be achieved by improving soil structure. Do not over-lime. Apply chelated iron and manganese treatments, such as Sequestrene, to the soil around the plant roots.

Sulfur deficiency in tomato plants

This leaf shows a general overall chlorosis while still retaining some green color. The veins and petioles exhibit a very distinct reddish color. The visual symptoms of sulfur deficiency are very similar to the chlorosis found in nitrogen deficiency. However, in sulfur deficiency the yellowing is much more uniform over the entire plant including young leaves. The reddish color often found on the underside of the leaves and the petioles has a more pinkish tone and is much less vivid than that found in nitrogen deficiency. With advanced sulfur deficiency brown lesions and/or necrotic spots often develop along the petiole, and the leaves tend to become more erect and often twisted and brittle.

Whenever the S status of growing plants drops below the critical level required, visual symptoms of S deficiency start appearing on the plant. The appearance of such symptoms indicates a serious condition because crop yields can decrease even without the appearance of such symptoms.

Role of sulphur in tomato plants

Sulfur is important for tomato yield. Uptake of sulfur is around 1.2lb/t of fruit. It is required throughout the season, and should be timed similar to nitrogen supplies. It maintains plant's vigorous growth..

Sulfur is a key component in the formation of several organic compounds that help give vegetables, like tomatoes, their flavor. Sulfur is essential for protein synthesis and is a component of the amino acids methionine, cysteine and cystine. Sulfur deficiency symptoms are slow to develop in the plant and often resemble symptoms of nitrogen defi- ciency. Evidence of a sulfur deficiency could include: hard and woody stems, elongated stems, and yellowish green lower leaves. Plants grown in sulfur deficient soils tend to be high in carbohydrates and nitrogen.

Symptoms of sulphur deficiency

Deficiencies are very rare in greenhouses, though can be found in crops grown in peat substrates where no sulfur fertilizer is used. Tomato plants lacking sulfur are shorter in height. The leaves are stiff and curled downward. They develop an interveinal chlorosis turning a yellowish green to yellow. Stems, veins and petioles turn purple. Necrotic spots can appear at the margins and tips of older leaves, and on the stems. Sulfur deficiency is similar in appearance to nitrogen deficiency, however it begins in the younger leaves because sulfur is not as mobile as nitrogen within the plant.

Sulphur deficiency symptoms in many ways resemble those of N - that is, the leaves become pale-yellow or light-green. Unlike N, S-deficiency symptoms appear first on the younger leaves, and persist even after N application. In cotton, tobacco and citrus, some of the older leaves are affected first.

Plants deficient in S are small and spindly with short and slender stalks, their growth is retarded, maturity in cereals is delayed, nodulation in legumes may be poor and N-fixation reduced, fruits often do not mature fully and remain light-green in color, forages contain undesirably wide N:S ratio and thus have lower nutritive value.

Treatment

It is important to soil test for sulfur and adjust levels and pH before planting a tomato crop or any crop. When S deficiency symptoms have been confirmed, soil application through a material containing readily available S such as one in the sulphate form should be applied.

Compost and gypsum are both reliable sources of sulfur. Super-phos- phate, potassium sulfate, and potassium magnesium sulfate are also options, but would require a soil test analysis to determine the major nutrients needed in addition to sulfur. In general, about 20 lbs of sulfur per acre is enough to ensure that the appropriate amount of sulfur for vegetable production. Vari- ous forms of sulfur are also used to reduce soil pH in alkaline soils.

Magnesium deficiency in tomato plants

Magnesium-deficient tomato leaves show advanced interveinal chlorosis, with necrosis developing in the highly chlorotic tissue. In its advanced form, magnesium deficiency may superficially resemble potassium deficiency. In the case of magnesium deficiency the symptoms generally start with mottled chlorotic areas developing in the interveinal tissue. The interveinal laminae tissue tends to expand proportionately more than the other leaf tissues, producing a raised puckered surface, with the top of the puckers progressively going from chlorotic to necrotic tissue.

Role of magnesium in tomato plants

Magnesium is required for many processes including transfer of energy and protein synthesis. With 20-25 % of the plant’s total magnesium localized in the chloroplasts, it is particularly important for chlorophyll production.

Magnesium is particularly important in ensuring even ripening of well-formed fruit.

Vegetative Growth - Maximize concentrations in leaf tissue prior to flowering
Flowering - Fruit Set Improve flowering and crop production – maximum requirements are at this stage
Fruit Ripening - Maturity Maximum requirements are at this stage for quality fruit production

A regular supply is needed throughout the life of the crop. Up to 54lb/ac of magnesium is used by a tomato crop. Magnesium uptake can be depressed by an excess of other cations, so it is important to maintain a correct balance. Particular care is needed in fertigation systems.

Symptoms of magnesium deficiency

Symptoms of magnesium deficiency start at the bottom of the plant on older leaves and then works their way upward. Fruits appear to ripen evenly but maturity is often delayed. Deficiencies may also occur in the middle of the plant during heavy fruit load, but this is usually transient. Where deficiencies are less severe, older leaves look brittle and their interveinal tissue is curled up. Where deficiencies are severe, chlorosis between the veins progresses from the margins to the middle of the leaflets. The small veins also become chlorotic, but the bigger veins remain dark green. With ongoing magnesium starvation, the interveinal chlorosis becomes more intensive, the color turns to bright yelloworange and necrotic spots may appear, which can grow together into brown bands. Finally, the older leaves die and the whole plant turns yellow and fruit yield is severely reduced.

Remedy

In the short term, apply Epsom salts as a foliar feed in summer. Dilute the salts at a rate of 20g of Epsom salts per litre of water (1/3oz per pint) plus a few drops of liquid detergent. Apply two or three times at fortnightly intervals, spraying in dull weather to avoid leaf scorch. In the long term apply to the soil around the roots either Dolomite limestone (calcium-magnesium carbonate) at 100g per sq m (4oz per sq yd) or Epsom salts (magnesium sulphate) at 30g per sq m (1oz per sq yd). Dolomite limestone will make the soil more alkaline, so should not be used around ericaceous (acid-loving) plants such as rhododendrons or camellias, or where the soil is already alkaline.

A gardener's voice

Read this article to know more about magnesium deficiency-

About four days ago I noticed my tomato plant's leaves were turning yellow, but the veins were still green. This is a sure sign of a magnesium deficiency and can kill plants if not treated. But, luckily, its easy and cheap to cure. 

Potted plants and seedlings in trays can experience soil depletion. Meaning, the plants soak up all the nutrients in the soil and will start to show signs of stress and nutrient deficiency. It's important to keep those plants "fed" with fertilizers, and there are lots of organic options to help keep plants healthy. Tomatoes are especially "hungry" plants, during their growing and fruit producing stages they are what I call "nutrient supersoakers". Tomatoes like plenty of nitrogen, and magnesium. Before transplanting your tomatoes outside dump wood ashes on your soil and mix in with the soil to prevent a strong wind from carrying away your ashes. Ideally, you want to let the ashes "soak" into the soil for a few months, but if you are pressed on time, some ashes are better than none. We have a wood stove that we use for heat over the winter and we have been dumping wood ashes on our garden beds all winter, the snow was excellent for packing the ashes down into the soil for deep soaking. Giving your plants magnesium is as easy as buying Epsom Salt. Epsom Salt is actually Magnesium Sulfate, not salt, so it is an excellent organic source of magnesium for your plants. 

Once I noticed the deficiency in my tomato plants, I went out and bought some Epsom Salt. If a magnesium deficiency is left untreated, the leaves will eventually turn yellow, and the veins, and the leaves will die and fall off. I mixed one to one and a half tablespoons with warm (not hot) water in a gallon jug and shook the jug until most of the "salt" had dissolved. The nice thing about Epsom Salts is that it dissolves quickly. I poured the water into one of the empty cells in my seed trays (I like to leave an empty cell to check water levels). Once the water level in my tray reached a little less than half, I poured the remaining water into a spray bottle and gently sprayed the tomato leaves with the water/salt mixture. By filling the seed tray and spraying the leaves, I am helping ensure that both the roots and the leaves receive the magnesium immediately. 

For the past four days, I have gently sprayed the water/salt mixture on the leaves. Water levels in my seed tray show the plants still have plenty of water. After four days, I saw significant improvement in the health of my plants. The leaves are still slightly yellow, so I will continue my treatment until the yellowing has disappeared.

Healthy plants = successful transplanting. I am planning (weather permitting) to transplant my tomato plants outside in my garden beds in three to four weeks. If my plants are to survive the stress of transplanting, they need to be as healthy as they can be. Good luck on your spring gardening!

 Now you may have known what to do with the plants with magnesium deficiency. So enjoy!

Calcium deficiency in tomato plants - blossom end rot

If you see a dark, rotting spot on the bottom of your tomatoes, it’s blossom-end rot. This problem, caused by a calcium deficiency, can be solved a few ways.

These calcium-deficient leaves show necrosis around the base of the leaves. The very low mobility of calcium is a major factor determining the expression of calcium deficiency symptoms in plants. Classic symptoms of calcium deficiency include blossom-end rot (BER) burning of the end part of tomato fruits (Fig. 17). The blossom-end area darkens and flattens out, then appearing leathery and dark brown, and finally it collapses and secondary pathogens take over the fruit.

All these symptoms show soft dead necrotic tissue at rapidly growing areas, which is generally related to poor translocation of calcium to the tissue rather than a low external supply of calcium. Plants under chronic calcium deficiency have a much greater tendency to wilt than non-stressed plants.

When tomatoes develop a sunken, rotten spot on the end of the fruit, the cause came long before you found the problem. It’s called blossom end rot, and here is why it happens.

Required calcium in tomato plants

Calcium is required in relatively large amounts. In total around 152lb/ac of calcium is taken up by a filed tomato crop yielding around 44.6t/ac. As calcium is needed during the whole growth period and its transport into the fruits is slowly, it is common practice to use applications throughout the season to build up levels in the crop tissue and again during fruit maturation, maximizing quality potential and storability.

Role of calcium in tomato plants

Calcium is a key component of cells holding the structure of cell walls and stabilizing cell membranes. It also has a direct influence on the salt balance within plant cells and activates potassium to regulate the opening and closing of stomata to allow water movement from the plant. 

Calcium enhances pollen germination; regulates some enzyme systems; and influences the growth and health of cells and conductive tissues. It has a key specific influence on tomato fruit quality especially Blossom End Rot (BER).

Calcium is required for growth and yield and promotes the earliness of fruit development.

Establishment - Boost root and leaf growth
Vegetative Growth - Maintain vigorous plant growth
Flowering – Fruit Set Maximize crop reproductive development
Fruit Ripening - Maturity Maintain good fruit firmness and quality and reduce BER risks

Causes of calcium deficiency (blossom-end-rot)

Vegetables need calcium for healthy development. When tomatoes can’t get enough from the soil, the tissues on the blossom end of the fruit break down. The calcium shortage may be because the soil lacks calcium, or calcium is present but is tied up in the soil chemistry because the pH is too low. Also, drought stress or moisture fluctuations can reduce its uptake into the plant. Another reason is that too much fertilizer causes the plant to grow so fast that the calcium can’t move into the plant quickly enough.

While blossom end rot is caused by a lack of calcium to the developing fruits, it doesn't mean there isn't enough calcium in the soil. It is most often related to an inconsistent amount of water in the soil or being taken up by the plant. Calcium is brought to the fruit in the water the plant takes up from the soil so allowing the soil to dry out too much between waterings can cause blossom end rot. Pot-grown tomatoes are especially susceptible.

Symptoms

A water-soaked spot at the blossom end of tomato fruits is the classic symptom of blossom-end rot. This relatively common garden problem is not a disease, but rather a physiological disorder caused by a calcium imbalance within the plant. It can occur in pepper, squash, cucumber, and melon fruits as well as tomatoes.

Blossom-end rot is most common when the growing season starts out wet and then becomes dry when fruit is setting. Damage first appears when fruits are approximately half their full size. The water-soaked areas enlarge and turn dark brown and leathery. These areas will eventually begin to rot, so the fruit should be picked and discarded.

Several factors can limit a plant’s ability to absorb enough calcium for proper development. These include: fluctuations in soil moisture (too wet or too dry), an excess of nitrogen in the soil, root damage due to cultivation, soil pH that’s either too high or too low, cold soil and soil high in salts.

The most obvious deficiency symptom is BER. However, deficiency results in scorching of the new growth and death of the growing point in both the roots and shoots. The leaves of seedlings become distorted and develop yellow, brown or purple necrotic areas starting at the leaf margin and moving into the interveinal areas. The growing point soon dies. In mature plants, the edges of the youngest leaves become brown, and some interveinal areas turn yellow. The growing point dies and the flower buds fail to develop. In the field, BER is more frequent on acid soils and those with a high salt content and can also cause vascular breakdown at the base of the plant, leading to wilting. It is prevalent under low soil moisture conditions. Crops grown on calcareous soils will also need calcium, as the element is not necessarily plant available due to its low solubility. Where calcium is supplied in excess, magnesium and potassium deficiencies may arise as a result of nutrient imbalance.

Prevention and control

Once fruits begin to form, water to supply 1-2" per week from rain and irrigation combined. Water deeply 1-2 times per week rather than frequent shallow waterings to promote good root growth. Water is drawn into the plant partly in relation to the amount of water lost from the leaves via transpiration. Transpiration slows down when there is high humidity, resulting in less water being needed from the soil. Less water from the soil = less calcium coming into the plant so extended periods of high humidity can also result in blossom end rot.

The best way to see if there is a pH problem or calcium deficiency in the soil is to get a soil test done. The best pH for tomato is 6.0-7.0 and if it's already there, you don't want to add lime which will raise the pH. A mulch can help the soil retain moisture. Other tips include not planting the tomatoes when the soil is too cool (affects early fruits), don't overfertilize with nitrogen, and be careful not to injure the roots if cultivation is needed near the plants. Some sources recommend calcium chloride sprays on the foliage but use caution with these. They can cause plant injury and some reliable sources say they don't really help.

Start now by testing the soil

Although most vegetables do well with a soil pH of 6.2 to 6.8, for those with blossom-end the pH should be 6.5 to 6.8 to free more calcium in the soil chemistry. Test results will indicate the amount of lime to add. Even better, lime also contains calcium. Work the lime into the top 12 inches of soil. Use a lime labeled “fast-acting,” which is better than ground limestone unless you have weeks to wait for the lime to react in the soil. If the pH is already correct, the soil test will recommend a different calcium source, such as gypsum. Also, add crumbled egg shells to your compost or bury them in your garden over time to help maintain the calcium levels.

Don’t over-fertilize

Too much nitrogen during early fruiting, especially with nitrogen made from ammonia, ties up calcium in the soil chemistry.

Avoid moisture stress

Use mulch to keep the soil evenly moist. Vegetables need about 1 to 1 1/2 inches of water a week while fruiting. The best way to water tomatoes planted in the ground is with a soaker hose. In hot climates it is especially tricky to keep big tomato plants in pots watered well during the summer. Make sure to water them daily or set them up on a drip system with a timer.

As a stop-gap measure, spray tomato plants with a calcium solution made for blossom-end rot

Follow label directions. Apply two to three times a week, beginning when the first blooms appear. This is not a long-term fix, but it may salvage your crop until you can take the steps mentioned above. The spray seems to work better on tomatoes than other vegetables.

Potassium deficiency in tomato plants

The leaves on the right-hand photo (below) show marginal necrosis (tip burn). The leaves on the left-hand photo show more advanced deficiency status, with necrosis in the interveinal spaces between the main veins along with interveinal chlorosis. This group of symptoms is very characteristic of K deficiency symptoms.

The onset of potassium deficiency is generally characterized by a marginal chlorosis, progressing into a dry leathery tan scorch on recently matured leaves. This is followed by increasing interveinal scorching and/or necrosis progressing from the leaf edge to the midrib as the stress increases. As the deficiency progresses, most of the interveinal area becomes necrotic, the veins remain green and the leaves tend to curl and crinkle. In contrast to nitrogen deficiency, chlorosis is irreversible in potassium deficiency. Because potassium is very mobile within the plant, symptoms only develop on young leaves in the case of extreme deficiency.

Role of potassium in tomato plants

High levels of potassium provide high yields in tomato crops. Tomatoes have a relatively high potassium requirement. There is usually 5.2 to 7.2 lb (approx. 2.36 to 3.27 kg) of K taken into the plant for every tonne (1000 kg) of tomato harvested.

Establishment - Promote strong early growth
Vegetative Growth - Maximize concentrations in leaf tissue prior to flowering
Flowering - Fruit Set Maintain plant growth and maximize flower numbers
Fruit Ripening - Maturity Maximize high potassium levels in the fruit and minimize disorders

Tomato plants need potassium because:

• It is essential for protein synthesis.
• It is important for breakdown of carbohydrates, a process which pro- vides energy for plant growth.
• It helps control ionic balance.
• It is important for the movement of heavy metals such as iron.
• It helps the plant to overcome and ward off plant diseases.
• It is important for fruit formation.
• It improves hardiness to overcome adverse weather conditions.
• It is involved in the activation of more than 60 plant enzyme systems that regulate grow rates.
• It assists in controlling guard cells that open and close stomata on the under- sides of leaves that can reduce stress during drought.

Therefore, potassium deficiency can cause poor plant growth and reduce overall yield. It is important to soil test for potassium and adjust levels and pH before planting a tomato crop or any crop. Tissue testing tomato leaves is also a way to monitor potassium levels during the season to ensure proper fertilization through the drip system or as a side-dress application.

Tomatoes have a relatively high potassium requirement compared to nitrogen with over 267 lb/ac of potassium typically being utilized. Potassium is needed throughout the season and is a major component of the fruit at around 250mg K per 100g of fruit. It is essencial to maintain a good balance of potassium with magnesium and calcium. Too much potassium restricts the uptake of these other cations. Use of high levels of potassium is particularly important under saline conditions to maintain plant growth. Excess sodium reduces the uptake and transfer of potassium through the plant and thus potassium levels need to be increased in order to maintain plant growth.

Symptoms

The leaves become dark green and yellowish to white necrotic dots develop near the leaf margins of the older leaves. These merge into brown necrotic areas around the leaf margins. Greenhouse grown tomatoes will often express K deficiency as ‘blotchy’ ripening. The fruit also lacks firmness and has low brix levels.

Deficient plants may be more prone to frost damage and disease, and their symptoms can often be confused with wind scorch or drought.

In tomatoes, the stems are woody and growth is slow. Leaves are blue-green in color, and the intervenal area often fades to a pale gray color. Leaves may also have a bronzed appearance and yellow and orange patches may develop on some of the leaflets. Fruits often ripen unevenly and sometimes have green patches near the stalks.

As potassium is mobile in the plant, it moves to the younger leaves when supplies are short. Although the growth of deficient plants may not be seriously impaired, the yield and quality of fruit are often greatly reduced. Deficient crops are prone to wilting.

Potassium deficiency causes yellowing and scorching of older leaves. These symptoms begin at the margins of the leaf and spread between the veins towards its centre. Large areas of tissue around the major veins remain green until the disorder is well advanced. A brown scorch develops in the yellow areas and spreads until the leaf is dry and papery. As each leaf dies, others further up the plant develop the same symptoms. These symptoms can develop rapidly in hot weather. Fruit may not expand fully at the stem end, although they look swollen at the tip end, a symptom that is also caused by water stress.

Prevention and treatment

Prevention and cure can be achieved in the shorter term by feeding with home-made comfrey liquid, adding seaweed meal, composted bracken or other organic potassium-rich fertilizers. In the longer term the soil structure should be improved by adding plenty of well rotted compost or manure. Wood ash has high potassium content, but should be composted first as it is in a highly soluble form. Common forms of inorganic fertilizers include: Potassium Nitrate, Potassium Sulfate, and Monopotassium Phosphate.

Potassium from a fertiliser side-dressing will move from the soil surface to the roots only if the soil is very sandy. A soil test can be used to determine the rate needed. Fertigation or drip feeding can also be used to treat a deficient crop. Foliar sprays are less effective and can burn leaves.

Phosphorus deficiency in tomato plants

A phosphorus deficiency in your plants will cause stunted growth and prevent them from producing fruit as expected, yet is is often overlooked or misdiagnosed as a nitrogen deficiency or simply as poor soil. Although it is a bit difficult to determine for the untrained eye, with a little effort you can lean to recognize signs that your plants are suffering from a phosphorus deficiency. Correcting the problem early will resolve the issue and your plants will thrive.

Left - Normal plant
Right - Phosphorus deficiency

The necrotic spots on the leaves on the figure are a typical symptom of phosphorus (P) deficiency. As a rule, P deficiency symptoms are not very distinct and thus difficult to identify. A major visual symptom is that the plants are dwarfed or stunted. Phosphorus deficient plants develop very slowly in relation to other plants growing under similar environmental conditions but with ample phosphorus supply.

Phosphorus deficient plants are often mistaken for unstressed but much younger plants.

Developing a distinct purpling of the stem, petiole and the lower sides of the leaves. Under severe deficiency conditions there is also a tendency for leaves to develop a blue-gray luster. In older leaves under very severe deficiency conditions a brown netted veining of the leaves may develop.

Need of phosphorus

Phosphorus is not needed in large quantities. Around 44.6lb/ac is all that is required during the season for field grown crops. Phosphorus is used during early growth ensuring a good start for the crop and again at flowering and fruit set.

Establishment - Maximize root development
Vegetative Growth - Ensure continued growth
Flowering - Fruit Set - Fruit development
Fruit Ripening - Maturity - Boost tomato nutritional quality

Symptoms of phosphorus deficiency

When deficient in phosphorus, tomatoes have rigidly erect leaves which are dark green to bluish green in color. The stems are thin and fibrous with a dull purple discoloration. Flowering and fruiting is poor, fruit are small and firm and yellow prematurely. In some cultivars, phosphorus deficiency can also appear as small brown areas which develop interveinally on the lower leaves.

These are the five symptoms of phosphorus deficiency:

1. Small thin stalks. Plants that do not receive enough phosphorus develop weak thin stalks that appear spindly. Healthy plants need strong stems to support the weight of fruit. Thin stocks not only are not able to support the fruit of the plant, they break easily in the wind and may not survive the season. If your plants fail to develop stocky stems, phosphorus may be the culprit.
2. Stunted growth. Plants suffering from a phosphorus deficiency may be stunted and short in stature. In initial stages they may appear healthy and look like much younger plants. If your plants are smaller than expected or smaller than other plants of the same age, they may need addition phosphorus.
3. Purple veins may appear on the leaves or the leaves may take on a purplish color. Check both the top and bottom of the leaf for purple veins. This is evident on new growth as well as older leaves. In severe cases the entire leaf may take on a purple hue.
4. Older leaves may appear bluish-green instead of the characteristic rich green of new growth. Unless the plant normally has a bluish tint, blue-green leaves signal a need for phosphorus.
5. Reduced blooms and/or onset of fruit. Phosphorus promotes blooming and fruit production. A deficiency may cause the plant to stop producing blooms or the blooms and fruits to be small and lack their usual color. For good fruit production plants require phosphorus.

Treatment

A phosphorus deficiency can be caused by inadequate amounts of phosphorus in the soil, but due to the nature of phosphorus absorption it can also be caused by low soil temperatures. This is particularly tree of tomatoes. Adding plastic mulch to increase soil temperatures may solve the problem. To increase the level of phosphorus in the soil apply high phosphorus fertilizer usually labeled as fertilizer for blooming plants. Water soluble fertilizer works the fastest and may bring results in a short period of time.

Nitrogen deficiency in tomato plants

Tomatoes (Lycopersicon esculentum), a summer staple in nearly every garden, are usually fairly easy to grow, even for the novice gardener. However, they can exhibit mysterious symptoms that challenge even the most experienced gardeners. Fruits, leaves or stems may become distorted or discolored, and the reasons behind the maladies can be diseases, irregular irrigation, pests or nutrient deficiencies. Tomatoes are hardy in U.S. Department of Agriculture plant hardiness zone 9 and above, but they can be grown almost anywhere during the summer months after the danger of frost has passed.

Nitrogen deficiency may cause yellow leaves on tomato plants. The first symptoms usually affect older, more mature leaves, and gradually the yellow color progresses to more and more leaves. Young leaves tend to stay green but may be smaller in size. In some cases, a red or purple cast can be seen on the veins. Usually, applying nitrogen fertilizer helps the new growth grow normally, but already yellowed leaves will not become green.

Role of nitrogen in tomato plants

Establishment - Promote strong early growth
Vegetative Growth - Ensure continued growth
Flowering - Fruit Set Maintain plant growth and maximize flower numbers
Fruit Ripening - Maturity In reduced amounts to maintain fruit fill

Damage and symptoms

Tomato leaves turn from their normal deep green to a pale green in the early stages of nitrogen deficiency. Then, the leaves gradually turn yellow. As this happens, the veins in the leaves stay green for a while before also turning yellow. The undersides of the leaves on some plants might get red or purple. If you do not correct the situation, then the older leaves will show signs of stress quite quickly when the plant does not get enough water. Tomato plants recover quickly when you apply some nitrogen in a foliar feeding. Follow up by adding nitrogen to the soil.

Nitrogen deficiency causes plants to grow slowly and thinly. Leaf production will be sparse and what leaves there are will be stunted. A purplish tint may be present. Older leaves will yellow. Note that some tomato varieties exhibit purplish tints naturally in healthy plants. This deficiency is easily treated with fertilizer with a nitrogen component.

Cause

Nitrogen promotes green, leafy growth and deficiency results in yellowing and stunted growth. Nitrogen is very soluble, so is easily washed out of the soil in winter rains, leaving the soil deficient in spring, just when plants are putting on new growth. Nitrogen deficiency is a common cause of yellow leaves in spring.

Remedy

In the long term, mulching with organic matter (such as well rotted garden compost or manure) provides a steady trickle of nitrogen to stabilise levels. In the short term, applying high nitrogen fertilisers such as sulphate of ammonia or poultry manure pellets will remedy the problem.

Follow these steps to treat nitrogen deficiency in tomato plants:

1. Test the soil components. Having your soil tested is important to confirm nitrogen and other nutrient deficiencies as well. You can get a soil test kit at your local garden center.
2. Determine what type of plants have nitrogen deficiency because this will determine the course of treatment. Be sure to follow the treatment plan for the type of plants affected.
3. Apply nitrogenous fertilizer to your vegetable plants as a side dressing. This may help increase your yield and avoid fertilizer burn.
4. Integrate nitrogen-rich fertilizer into the soil where you'll plant your vegetables the following spring as well. Choose a well-balanced fertilizer such as "Tomatoes Alive" by Gardens Alive, which has the added benefit of being an organic fertilizer.
5. Try applying well-rotted manure to your garden bed as well, which tends to be nitrogen rich. You may also use any fertilizer that has nitrate, ammonium or urea in the formulation.