Blossom end rot calcium

Garden Myths – Learn the truth about gardening

Blossom End Rot (BER) is a disfiguration found in fruiting vegetables, like tomatoes. It also affects peppers, watermelons, egg plants and apples. This problem is usually blamed on a shortage of calcium, but this turns out to be a myth.

Blossom end rot in tomatoes

Blossom End Rot – What is it?

Blossom End Rot or BER shows up as a small wet water-soaked spot at the blossom end of the fruit. Over time it darkens to a brown or black color and becomes leathery and hard. This is not a disease, as reported by many web sites, nor is it the result of insect damage. As the fruit grows, something goes wrong with the normal growth process and the cells in the fruit start to die. The dead cells turn black and hard. It is a physiological condition due to the plants environment.

BER is most common on the first fruits of the season, but it can occur at any time.

The fruit, once affected, will not develop properly, and can be discarded so the plant can focus it’s energy on newer fruit.

Blossom End Rot – What Causes it?

For years it was claimed that a lack of calcium was causing Blossom End Rot since fruit with BER had low calcium levels.

More recently, scientists have had a closer look. It turns out that the problem is one of moving calcium around inside the plant, not necessarily a shortage. Various ‘transporter’ compounds, such as gibberellins and a recently isolated protein are responsible for moving calcium to points in the plant where it is needed. Calcium is required for cell growth and so it is required in fairly large amounts by the developing fruit. When these transporter compounds are not doing their job properly, it results in low levels of calcium at specific points in the plant.

In the case of Blossom End Rot, the transporter compounds are just not moving enough calcium to the growing fruit.

You might be thinking to yourself that BER is a calcium deficiency, but that is not correct. The rest of the plant can have lots of calcium and BER can still develop. Compare this to a serious earthquake. The thing the affected people need most urgently is drinking water–they have a shortage. We don’t have a global shortage of drinking water–we just don’t have it in the right place at the right time.

Once you understand the real problem, it becomes obvious why many of the remedies for BER don’t work.

How do You Solve Blossom End Rot?

In many cases the plant seems to grow out of the problem over time. As mentioned above, the first fruit of the season is most likely to have the problem, and after that, fruit grows normally–for no clear reason.

The following are some solutions that have been proposed:

1) Fertilize with calcium. It is possible that the soil is deficient of calcium, and if this is the case fertilizing with calcium will help eliminate BER. However, most soil has lots of calcium and if it does have calcium, fertilizing with more will not help the problem. Too much fertilizer may exacerbate the problem by making it harder for the plant to absorb calcium. For example, excess ammonium from of nitrogen can make it harder for the plant to absorb calcium.

2) Spray calcium fertilizer on the leaves ie foliar feed. First of all, foliar feeding is not a good long term solution for feeding plants especially for home gardeners, at best it is a quick fix solution. Calcium in the leaves does not move away from the leaves because it only “moves in the plant via the xylem and moves with the transpirational water flow from the roots, up the plant and into growing points” (quoted from Dr. Linda Chalker-Scott). Calcium has no ability to flow from the leaves via the phloem to the developing fruit.

An interesting experiment measured the effects of calcium foliar spray on tomato plants and found that it affected both plant growth and reduced BER (ref 6). It is possible that the increase of calcium in the leaves results in more calcium being directed to the fruit from the roots. This is just one study, but calcium foliar spray may reduce BER.

3) Spray calcium on the fruit. Fruit has a tough waxy outer skin that is not very permeable, and it has no stomata to allow nutrients to enter. It is even less likely to absorb calcium than the leaves. This does not work.

4) Treat the plant with Epsom salts. I don’t know why people keep recommending Epsom salts to solve problems–it’s just silly. Epsom salts is magnesium sulfate–it does not contain calcium! Blossom End Rot has nothing to do with a magnesium shortage.

5) Water more, or less. There is some evidence that water levels in the plant play a role in calcium levels in various parts of the plant, and water levels may have an effect on the transporter compounds. The problem with this advice is that it is difficult to know if you need to increase or decrease water levels. Keep the soil moist and don’t over water.

6) Grow a different variety of tomato. This can work. Some varieties are more likely to get Blossom End Rot so growing a different variety could solve the problem for you.

7) Adding bonemeal or lime to the soil. Both these products contain calcium and if your soil is deficient of calcium, these might help. Keep in mind most soils are not deficient of calcium, so I would not use these products until you have a soil test done.

8) Don’t over fertilize with nitrogen. This is important and can contribute to BER. Too much nitrogen causes the plant to grow more leaves. As water is drawn towards the leaves, it carries calcium with it which may in turn reduce the amount of calcium going to the fruit. Over fertilization also increases the amount of salts around the roots, which makes it harder for the plant to absorb calcium.

There is no magic bullet to solve Blossom End Rot. Treat plants the way they want to be treated (good soil, compost, regular water etc) and you should not have serious problem. But if you do have BER, don’t believe everything you read.

1) Blossom End Rot by RHS: http://rhs.org.uk/advice/profile?pid=395

2) Why Calcium Deficiency is Not the Cause of Blossom End Rot in Tomato and Pepper Fruit: http://www.sciencedirect.com/science/article/pii/S0304423814002830

3) de Freitas, Sergio Tonetto; Mitcham, Elizabeth Jeanne; Jiang, Cai-Zhong. 2012. Mechanisms Involved in Calcium Deficiency Development in Tomato Fruit in Response to Gibberellins. Journal of plant growth regulation, v. 31, no. 2, p. 221-234

5) Blossom End Rot – Transport Protein Identified: http://phys.org/news/2011-11-blossom-protein.html

6) Effect of Foliar Application on Tomato Growth: http://www.bepls.com/feb_2014/7.pdf

7) Photo Source: NC State University

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Journal of Plant Nutrition

Blossom-end rot (BER) is a common physiological disorder that occurs on the fruit of tomato (Lycopersicon esculentumMill.), pepper (Capsicum annuumL.), eggplant (Solanum melongenaL.), and watermelon . BER may occur in all the tomato-producing areas of the world and has been shown to create losses up to 50%. BER is related to many factors including: high salinity, high magnesium (Mg), ammonium (NH4), and/or potassium (K) concentration, inadequate xylem tissue development, accelerated growth rate, unfavorable moisture relationships (high, low, or fluctuating), low soluble soil calcium (Ca), high temperature, and high and low transpiration, but the underlying cause of this disorder is an inadequate amount of Ca in the blossom-end of the fruit. Although it is widely accepted that a local Ca deficiency plays an important role in the induction of BER, there are also some claims that Ca deficiency is not the cause of BER as a critical level of Ca for BER induction has not been found. To prevent BER from occurring, an understanding of Ca in the soil, uptake and translocation of Ca, and the factors affecting these processes, is necessary.

Tomatoes are a delicious fruit that is grown in most vegetable gardens. While they’re officially a fruit, they are more commonly eaten as a vegetable. They can be eaten raw in salads, and made into sauces and stews. They’re a versatile plant that isn’t too difficult to grow, as long as you follow the growing instructions.

Like other edible plants, tomatoes require a fertilizer to provide nutrients to the tomato plants. This encourages growth of plant and tomato. One of the best fertilizers for tomatoes is calcium nitrate. This is a fertilizer that is made of two different nutrients. Its appearance is white and grainy, and like other types of fertilizers, it also dissolves completely in water, enabling for simple spray application.

Calcium nitrate contains 26.5 percent of calcium and the 15.5 of the percentage is nitrate nitrogen. This fertilizer is also suitable for use in greenhouses where there is drip irrigation. The tomatoes can also be watered by hand for outdoor gardens. The fertilizer is applied after the tomatoes plants have been planted into the ground.

Advantages of Using Calcium Nitrate for Growing Tomatoes

Calcium nitrate provides many benefits to tomato plants that no other type of fertilizer can provide. It’s a safe method of fertilizing, and has few negatives. It provides two of the most basic nutrients to tomato plants that they need: nitrate nitrogen and calcium. Calcium nitrate works well for most plants that reside in soil, and works in many different types of climates around the world.

Another great benefit of using calcium nitrate is because of the full absorption by the tomato plant roots, so no residue is left behind. This can be a concern which can occur with other types of fertilization. The soil will also not be left salty. This water-soluble fertilizer is easily absorbed, and is a better way to provide the plant with calcium and nitrogen requirements.

The nitrate form of nitrogen is the preferred form of nitrogen for tomato plans. This helps the plant to absorb other nutrients too. It will allow soils that are rich in clay to better transfer nutrients to the tomato’s roots. All plants, including tomato plants, require calcium, and they consume a great amount of it. Often plants can’t derive calcium from the soil because it’s not in a form that they can use, yet it’s the number one nutrient that is required to make them grow. This is one of the number one reasons why you should be fertilizing your tomato plants with calcium nitrate.

More Benefits of Using Calcium Nitrate for Tomato Plants

Calcium nitrate can assist the soil in providing minerals in a form that is more easily utilized by the plant, even in difficult clay soil conditions. The calcium will force the separation of the clay, layer by layer, making it more porous.

Calcium nitrate will encourage tomato plants to grow more quickly, and provide a greater yield of fruit. The plant will better be able to build up their resistance to disease and pests. The fruit will last longer on the vine, enabling more fruit to be enjoyed in meals. The tomatoes will last longer during transport, and be allowed to be stored for longer, without the addition of harmful preservatives.

Calcium nitrate can also allow a more rapid absorption of nutrients by the plant than if they had simply been left alone to grow on their own. Calcium nitrate allow contains no fillers or additives. It’s a chemically-derived fertilizer that contains elements. This type of fertilizer will not steam, wash, or burn up the soil or plant. It also doesn’t create alkaline conditions in the soil, and does not leave any lingering salt behind in the soil. The soil can easily be cultivated for plants the following year.

Application Method

Since calcium nitrate is easily water-dissolvable, the best application method to plants is by a foliar spray. A foliar spray is made by mixing water with the calcium nitrate in a bucket, and then pouring into a spray bottle. You will then use the spray bottle to spray the plant or soil, but to never do both at the same time.

Before planting your tomato plants it’s best to learn how to space them apart for the best growing conditions. Ideally you want to space your tomato plants about two to three feet apart in rows that are four to five feet apart.

To calculate how much calcium nitrate to buy at the store, you’ll need one gallon of solution for every twenty to fifty square feet of garden space.

A foliar spray can be used on tomato plants grown in a garden, in a hothouse or greenhouse, plants grown on a patio in a controlled environment, and even tomatoes that are grown indoors like house plants.

You’ll need the follow items to mix up your fertilizer :

  • Calcium nitrate
  • Water
  • A Bucket
  • A Spoon
  • One Plastic Spray Bottle
  • Measuring Tablespoon

Method

To mix up the calcium nitrate you’ll need to mix four level tablespoons of calcium nitrate into one gallon of water, in a bucket. Use a garden spoon to ensure that all of the calcium nitrate has been thoroughly dissolved. Pour some of the fluid into a spray bottle and twist on the spray lid. You can cover the remainder in the bucket until you need it again, but it’s recommended you use it up in one day.

How to use Calcium Nitrate for Tomatoes

After you have mixed up your calcium nitrate solution you’ll be ready for spray application to your garden. For the best application method, wait until your tomato plants have grown to at least the second set of blossoms.

After you see these second set of blossoms, you can the apply your spray to the tomato leaves two or three times a week.

The second way to apply calcium nitrate to your plants is a side dressing directly into the soil. The amounts will differ. You’ll need about four ounces of spray solution for every seven to ten feet of tomato rows. You’ll mix your solution directly into the first one inch of surface soil, and avoid getting it on the leaves if you chose to do this method.

Other Uses of Calcium Nitrate in Garden

Calcium nitrate has many other benefits for the garden, and not just for tomatoes. Since all plants require calcium and nitrate nitrogen to grow, it can be a great fertilizer for the entire yard, including grass.

But there are many vegetables that are commonly grown in the garden, and the calcium nitrate can also suitable for them. All types of vegetables can benefit from using fertilizer, rather than nothing. These include broccoli, cabbage, cauliflower, celery, lettuce, and spinach. The recipe and application method is similar to the application for tomato plants.

Tips for Growing Tomatoes

Since tomatoes are a garden staple they can benefit from other growing tips to ensure that yours are the largest, and firmest, yet taste good too.

When you’re first planting your seedlings, don’t crowd them together. Ensure they have plenty of space from each other. Also ensure they are grown in a part of the garden that gets lots of light. Don’t plant them below a sun-blocking bush or tree. If you are growing them in a greenhouse or indoors, ensure you have adequate electrical lighting for them.

  • Must Read : How to Fertilize Tomato Plants with Epsom Salts

Indoor plants love a bit of a breeze, and this can be replicated by a fan. Before planting outdoors, cover the planting bed with a black plastic sheet. This will heat up the ground. Seedlings love soil warmth, and this will encourage them to grow faster. When you plant your seedlings, bury them deeper in the ground than when they were planted in their seedling pots. This encourages root growth. Many people like to bury their plants sideways. They’ll soon raise up as they grow toward the sun.

Don’t immediately mulch the ground. Do it after the ground has heated up. When your tomato plants have grown to a length of three feet remove the leaves that are from the ground and up to one foot. These are usually the leaves that will first develop fungus as soil-born pathogens will spray upwards. You can use a compost tea spray to prevent this.

Even soil that contains a lot of calcium carbonate, or lime, doesn’t necessarily mean that plants can utilize this form of the nutrient. This is why a good fertilizer such as calcium nitrate will provide the nutrients that your tomatoes and other vegetables in the garden need. The calcium carbonate in soil does not dissolve well in water, making calcium nitrate a better form of plant nutrient. Remember that if you’re using calcium nitrate to not use any other agricultural chemical on your tomato plants.

Keep your calcium nitrate in closed packages and in a dry, moisture-free spot in the garden shed. With some attention to detail, you’ll experience a better crop of tomatoes this year.

Applying Calcium Nitrate For Tomato Blossom End Rot

It’s midsummer, your flower beds are blooming beautifully and you’ve got your first little vegetables forming in your garden. Everything seems like smooth sailing, until you see mushy brown spots on the bottom of your tomatoes. Blossom end rot on tomatoes can be extremely frustrating and once it has developed, there’s not a lot that can be done, except to patiently wait and hope that the matter will cure itself as the season progresses. However, using calcium nitrate for tomato blossom end rot is a preventative measure you can do early in the season. Continue reading to learn about treating blossom end rot with calcium nitrate.

Blossom End Rot and Calcium

Blossom end rot (BER) on tomatoes is caused by a deficiency of calcium. Calcium is necessary for plants because it produces strong cell walls and membranes. When a plant does not get the amount of calcium needed to fully produce, you end up with malformed fruit and mushy lesions on fruit. BER can affect peppers, squash, eggplant, melons, apples and other fruits and vegetables, too.

Oftentimes, blossom end rot on tomatoes or other plants happen in seasons with extreme weather fluctuations. Inconsistent watering is also a common cause. Many times, the soil will have adequate calcium in it, but because of inconsistencies in watering and weather, the plant is not able to take up the calcium properly. This is where patience and hope comes in. While you can’t adjust the weather, you can adjust your watering habits.

Using Calcium Nitrate Spray for Tomatoes

Calcium nitrate is water soluble and is often put right into the drip irrigation systems of large tomato producers, so it can be fed right to the root zone of plants. Calcium only travels up from plant roots in the plant’s xylem; it does not move downward from the foliage in the plant’s phloem, so foliar sprays are not an effective way of delivering calcium to the plants, although calcium rich fertilizer watered into the soil is a better bet.

Also, once fruit has grown ½ to 1 inch large, it is unable to absorb anymore calcium. Calcium nitrate for tomato blossom end rot is only effective when applied to the root zone, while the plant is in its flowering stage.

Calcium nitrate spray for tomatoes is applied at a rate of 1.59 kg. per 100 feet of tomato plants or 340 grams per plant by tomato producers. For the home gardener, you can mix 4 tablespoons per gallon of water and apply this directly to the root zone.

Some fertilizers that are made specifically for tomatoes and vegetables will already contain calcium nitrate. Always read product labels and instructions because too much of a good thing can be bad.

Tomato

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 and yield

Calcium is required for growth and yield and promotes the earliness of fruit development, as studies in Italy show.

Top-dressing with calcium and Ca content in the fruit

The small amounts of calcium found in fruit are essential for the production of good quality tomatoes. Top-dressing with calcium nitrate is a successful method of boosting calcium in fruit, as trials in USA show.

Calcium and fruit firmness

Calcium is needed to maintain good fruit structure and quality. Adequate supplies improve tomato firmness and increases TSS, as shown in studies in Turkey.

Calcium uptake and ammonium

Ammonium based fertilizers are antagonistic to calcium uptake. They reduce soil pH and water uptake rate as well as slowing transpiration. When ammonium competes for uptake with calcium, it increases BER risks.

Calcium and BER

A lack of calcium is intrinsically linked to occurrence of BER. The use of ammonium as the main source of nitrogen, significantly increases the incidence of this disorder, as you can see in studies in Brazil.

Calcium nitrate and BER

As a general rule, fresh fruit with a calcium concentration of above 0.12% do not develop BER. The best way of ensuring good calcium supply is to use calcium nitrate as the calcium source (see data above from Turkey).

General guidelines for calcium application

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.

Calcium at tomato growth stages
Establishment Boosts root and leaf growth
Vegetative growth Maintains vigorous plant growth
Flowering – fruit set Maximizes crop reproductive development
Fruit ripening – maturity Maintains good fruit firmness and quality and reduce BER risks

Crop Guide: Tomato Fertilizer Recommendations

2. Soil-grown tomatoes

2a. Haifa NutriNet™ web software for Nutigation™ programs

Haifa fertilization recommendations are available online. Click on http://www.haifa-nutrinet.com to enter into NutriNet™, a unique software program, that will assist you to workout the recommended fertilizer rates at different growth stages according to the expected yield under your growing conditions.

The following is an example of recommendations of open field grown tomatoes on sandy loam soil, as determined by NutriNet, with the assumption of split scheduled fertilization into:
a) Base-dressing (pre-plant) fertilizers followed by:
b) Nutrigation (fertigation) at different growth stages, on sandy-clay soil when the expected yield is 120 ton/Ha:

a) Base-dressing:

B) Nutrigation (fertigation):

Total amount of fertigated fertilizers

B) Nutrigation (fertigation):

Table 10: The total contribution of plant nutrients from each fertilizer as calculated by NutriNet™:

Table 11: Recommended nutrient rates per ha per day and per growth stage as calculated by NutriNet™:

Table 12: Recommended fertilizers rates per growth stage

Phase

Days from
sowing
/ planting

kg/ha/phase

Ammonium
nitrate
34-0-0

Multi-MAP™*
12-61-0

Multi-K®*
13-0-46

Mullti-Cal®*
15.5-0-0
+26CaO

Magnesium sulfate
(16% MgO)

Planting

Vegetative

Flowering

Fruit set

Fruit growth

1st harvest

Harvest

Harvest

Last harvest

Total

*
Multi-K® = Potassium nitrate
Multi-MAP™ = Mono-ammonium phosphate
Multi-Cal® = Calcium nitrate

Fertilization and fertigation rates may vary according to cultivar, growing method, climatic conditions, growth stages and expected yield. By using Haifa NutriNet™ (http://www.haifa-nutrinet.com) program on-line, you may obtain Haifa’srecommendations most suitable to your growing conditions by selecting the expected yield, growing method and growth stages.

2b. Tomato crop guide: Poly-Feed™ water-soluble NPK fertilizers

Table 13: Fertilization program for processing tomatoes. Expected yield: 50 ton/ha

Growth stage

Days

Poly-Feed™
formula

Kg/ha/day

Planting to flowering

Flowering to fruit set

14-7-21+ 2MgO

Fruit set to harvest

14-7-28+ 2MgO

Table 14: Fertilization program for tomatoes in tunnels. Expected yield: 150 ton/ha

Growth stage

Days

Poly-Feed®
formula

Kg/ha/day

Planting to flowering

Flowering to fruit set

14-7-21+ 2MgO

Fruit set to 1st harvest

14-7-28+ 2MgO

1st Harvest to Last harvest

14-7-28+ 2MgO

Table 15: Fertilization program for tomatoes in greenhouse. Expected yield: 160 ton/ha

Growth stage

Days

Poly-Feed™
formula

Kg/ha/day

Total kg/ha

Planting to flowering

Flowering to fruit set

Fruit set to 1st harvest

1st Harvest to Last harvest

To cure and prevent magnesium deficiencies, apply Magnisal™ by Nutrigation™ or foliar spray.
To cure and prevent calcium deficiencies, apply Multi-Cal™ by Nutrigation™ or foliar spray.

2c. Tomato crop guide: Multicote™ Agri Controlled Release Fertilizer

An N:P2O:K2O ratio of 2:1:3* is recommended, as pre-plant application. This application will take care of the nutritional requirement of the plot for the entire growth season.
Multicote® Agri granules should be incorporated into the soil, 10cm deep and 10cm away from the planting row.
Consult a local Haifa representative for detailed explanations and instructions.

Table 16: Multicote® Agri application recommendations tomato in greenhouse

kg/ha

Analysis*

Longevity

2,500 – 4,000

8 months

* The actual choice of formula should take into account soil type and addition of compost and any other factor that may affect the nutritional status of the soil.

2d. Tomato crop guide: Foliar nutrition

Foliar nutrition

Foliar feeding is a fast and highly effective method of supplementing and enriching plant nutrients when needed. Foliar application of Haifa water soluble fertilizers provides needed plant nutrients for normal development of crops when absorption of nutrients from the soil is disturbed, precision-timed foliar sprays are also a fast-acting and effective method for treating nutrient deficiencies.
Foliar application of the correct nutrients in relatively low concentrations at critical stages in crop development contributes significantly to higher yields and improved quality.

Determine safe foliar applied rate:
To verify the safe rate under local conditions, it is advisable to spray recommended rate on a few plants. After 3-4 days check the tested plants for scorching symptoms.

Preparation of tank-mix:
Dissolve Haifa water-soluble fertilizes in about half of the tank volume, and add to the spray tank. When applying together with crop-protection agents, addition of wetting agents is not necessary. To ensure compatibility of tank-mix components, a small-scale test should be performed prior to actual application.

Table 17: Haifa water-soluble fertilizers for foliar application:

3. Soilless-grown tomatoes

3a. Tomato crop guide: Straight fertilizers

There are different growth media with different physical and chemical characteristics. The following are general fertilization recommendations for all soilless growth media.

Fertilizer stock solution: Once dissolved, not all fertilizers are inter-compatible with each other. Therefore, they have to be split into two fertilizer tanks: A and B, according to their compatibilities. Fertilizers containing phosphorus (P) or sulfur (S) should be dissolved in Tank A only, while fertilizers containing calcium (Ca) or magnesium (Mg) should be dissolved in Tank B. Chelated micronutrients should be dissolved in Tank B, as well.

The concentration of the fertilizers stock solution depends on:

  1. The ambient temperature (higher ambient temperature enables higher concentration)
  2. The injection rate – how many liters of the fertilizer solution will be injected into each cubic meter (1000 liters) of the irrigated water

Dividing the injection capacity by one cubic meter should be the concentration of the fertilizer solution. If, for example, the injector delivers 5 L into each cubic meter of the irrigated water, multiply the amount of fertilizer dissolved in the tank by 200 (1000 L / 5 L = 200).

Examples of fertigation regimes in soilless grown tomatoes:
The following example was prepared to fit Dutch conditions (low transpiration and low water EC). Considerable and proportional reduction in the concentration of the macronutrients should be required to offset for lower quality water prevailing in other conditions.

Table 18: Nutrition database for tomatoes. Growth medium: rockwool.

Parameter

Nutrient solution (ppm)

EC (mS/cm)

N- NH4

N- NO3

P

H2PO4

K

Ca

Mg

S, total

SO4

Table 19: Recommended water-soluble fertilizers and their rates, to prepare the above recommended solution:

Fertilizers g/m3

Plant nutrients – g/m3 solution

NO3

NH4

P*

K*

Ca*

Mg*

S*

Ammonium nitrate

Multi-K®

K2SO4

Multi-Cal®

MgSO4

Multi-MKP™

Total

An Italian system for fertigation management in close-loop soilless culture of tomato are:

NO3

NH4

P*

K*

Ca*

Mg*

Ca*

14 30 310 160 35 80

Table 20: Recommended water-soluble fertilizers and their rates to prepare a fertilizer solution for the above Italian system:

Fertilizers g/m3

Plant nutrients – g/m3 solution

NO3

NH4

P*

K*

Ca*

Mg*

S*

Ammonium nitrate

Multi-K®

K2SO4

Multi-Cal®

Magnisal®

MgSO4

Multi-MAP™

Multi-MKP™

Total

EC value should be maintained at ~ 2.07 mS/cm

* conversion factors: P x 2.29 = P2O5 ; K x 1.20 = K2O ; Ca x 1.40 = CaO ; Mg x 1.66 = MgO ;
S x 3.00 = SO4

Table 21: Fertilizer recommendations for hydroponic (perlite, rockwool, and NFT) tomatoes in Florida(http://edis.ifas.ufl.edu/CV216):

Nutrient

Growth stage

Transplant to
1st cluster
1st cluster to
2nd cluster
2nd cluster to
3rd cluster
3rd cluster to
5th cluster
5th cluster to
termination
Final delivered nutrient solution concentration (ppm)**
N 70 80 100 120 150
P 50 50 50 50 50
K 120 120 150 150 200

Ca*

150 150 150 150 150
Mg* 40 40 40 50 50
S* 50 50 50 60 60

* Ca, Mg, and S concentrations may vary depending on Ca and Mg concentration in water and amount of sulfuric acid used for acidification.
** 1ppm = 1mg/liter

Table 22: Recommended water-soluble fertilizers and their rates to prepare a fertilizer solution from transplant to various growth stages as indicated in Table 21:

A. From transplant to 1st cluster

Fertilizers

g/m3

NO3

NH4

P*

K*

Ca*

Mg*

S*

K2SO4

150 63 23

Multi-Cal®

500 77.5 95

MgSO4

400 40 52

Multi-MKP™

45.4 56

Total

77.5 45.4 119 95 40 75

B. From 1st to 2nd cluster

Fertilizers

g/m3

NO3

NH4

P*

K*

Ca*

Mg*

S*

K2SO4

150 57

Multi-Cal®

500 95

MgSO4

400 40 52

Multi-MKP™

Total

* conversion factors: P x 2.29 = P2O5 ; K x 1.20 = K2O ; Ca x 1.40 = CaO ; Mg x 1.66 = MgO ;
S x 3.00 = SO4

C. From 2nd to 3rd cluster

D. From 3rd to 5th cluster

E. From From 5th cluster to Termination

* conversion factors: P x 2.29 = P2O5 ; K x 1.20 = K2O ; Ca x 1.40 = CaO ; Mg x 1.66 = MgO ;
S x 3.00 = SO4

Table 24: Recommended water-soluble fertilizers and their rates to prepare a fertilizer solution as indicated in Table 16 (above):

A. Planting and establishment

B. Flowering

C. Ripening and harvest

* conversion factors: P x 2.29 = P2O5 ; K x 1.20 = K2O ; Ca x 1.40 = CaO ; Mg x 1.66 = MgO ;
S x 3.00 = SO4 3b. Tomato crop guide: Poly-Feed™ water soluble NPK fertilizers

Poly-Feed® water soluble NPK fertilizers

Table 25: Recommended composition of nutritional solution for soilless-grown tomatoes
A. In temperate or cold climate with low sun radiation and soft water (e.g. North and North-East Europe, North France, UK, Japan, Korea)

Concentration in irrigation water (ppm)

Recommended
Poly-Feed® formula

Conc.
(kg/m3)

N

P

K

Ca

Mg

14-10-34+ME

Some acid and Multi-Cal® calcium nitrate should be added to adjust the pH and to complete calcium requirements.

B. In hot climate with high sun radiation and hard water (e.g. Middle East, Mediterranean countries)

Concentration in irrigation water (ppm)

Recommended
Poly-Feed® formula

Conc.
(kg/m3)

N

P

K

Ca

Mg

Some acid and Multi-Cal® calcium nitrate should be added to adjust the pH and to complete calcium requirements.

Need more information about growing tomatoes? You can always return to the tomato fertilizer & tomato crop guide table of contents

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