Tomatoes are one of the most popular of the vegetables (but its actually considered to be a fruit - a berry, to be exact) grown today. It's just about everyone who has at least one tomato plant, even if its in a clay pot on their back deck or high-rise patio. Some people grow them upside down in a bag and some people grow them right side up. Everyone will agree, though, that there's nothing quite like a home-grown, vine-ripened tomato.
This is because home-grown tomatoes taste better. And this is because they probably haven't been sprayed with fungicides or insecticides and the plants are probably the healthiest with the least stress because they get regular lots of attention, plenty of water and sunlight and maybe even an occasional dose of fertilizer.
But the same isn't true of commercially grown tomatoes that suffer from stress and nutrient deficiency that causes other issues and symptoms to appear such as fungal growth and insect infestation. Although tomatoes have an incredible potential for quality and yield, those produced under conventional farming conditions fall far short of their potential for taste, texture, storability, nutrient content and weight (moisture content).
A tomato plant goes through distinct stages of its life as the season progresses. During each of these stages, it will have distinct environmental and nutrient requirements that, if met, will eliminate or minimize the opportunity for quality and yield loss due to stress. Each time that an environmental or nutritional need is not met, the plant will experience yield loss. It is the additive affect of many small stresses that cause significant losses in quality and yield. The key to proper nutrition is more about the balance of nutrients than it is about the amount of nutrients.
We carefully formulate a blend of major and micro nutrients into our MaxMix and TrueBlend premix solutions. This takes the guesswork out of nutrient balance. Check out Triple Ten and TrueBlend today. Read about our Vegetable Program.
The four major elements which are particularly critical in the production of tomatoes are nitrogen, calcium, potassium and phosphorus.
When NH4 is the major nitrogen source, toxicity can occur resulting in a significant reduction in fruit yield. However, in initial plant development, NH4 is readily utilized and benefits early plant growth and development. However, when the tomato plant enters its reproduction stage, NH4 can adversely affect both plant growth and fruit yield and increase the incidence of blossom-end rot (BER) in fruit, a phenomenon that has been frequently observed and reported. Too much NH4 (greater than 25% of total nitrogen) can cause a decrease in the number and fresh weight of fruit and an increase in the number of fruit with blossom end rot (BER).
The lack of calcium is intimately tied to the occurrence of BER in fruit. However, the occurrence of this fruit disorder is not necessarily a calcium deficiency, but is more likely due to a combination of factors that restrict the movement of calcium into the plant and fruit. The most common inducing factor is moisture stress, due to either an excess or deficiency of water. High humidity and/or excess water conditions slow the transpiration rate of the plant. Since calcium moves in the plant in the transpiration stream, a reduction in water movement within the plant reduces the amount of calcium-carrying water reaching the developing fruit. Under water stress, the same phenomenon occurs and BER occurs in developing fruit. Any factor that would restrict the uptake of calcium through the roots, such as low soil pH and imbalance among the major cations, potassium and magnesium plus NH4, can interfere with Ca uptake. Having a sufficient concentration of calcium but it isn't the answer. Frequently, it is the balance among the major cations that interferes with calcium uptake.
An inadequate supply of potassium to the tomato plant will result in uneven fruit ripening, thereby reducing fruit quality. However, excessive levels of potassium can significantly interfere with the availability of magnesium and calcium. Potassium uptake by plant roots is significantly affected by soil aeration and temperature. If soil is too wet, potassium uptake will be reduced. It is wise to increase the potassium content in the nutrient solution when the tomato plant begins to fruit, but not so much that it interferes with uptake of calcium and magnesium.
Magnesium deficiency primarily occurs when there is an imbalance among the other major elements. Magnesium deficiency symptoms (interveinal chlorosis on the older leaves) can be an indication of some type of plant stress due either to low or high moisture or temperature conditions. A severe magnesium deficiency can result in BER in the fruit.
Those micro nutrients that have been specifically studied for tomato are boron, iron and zinc. Micro nutrient deficiencies occur on very sandy soils, on high pH soils, or in instances where major elements are available in excess. High plant manganese levels can occur when the soil is very acid, or in soil-free rooting mixes in which pine bark is a major ingredient and when phosphorus availability is high.
Boron deficiency will not likely occur unless there are unusual growing conditions, such as temperature and moisture stress, or on sandy soil low in organic matter content. Lack of adequate boron will result in poor fruit set and low fruit quality.
Under normal soil conditions, Iron deficiency is not likely to occur unless the soil is low in "available" Fe or above 7.0 in pH. Iron deficiency symptoms (light green to yellow leaves occurring on emerging leaves) occur when the plant is under stress from lack of adequate moisture, during periods of rapid plant growth, or changing light conditions.
Tomato plants can be Zn deficient without visual symptoms appearing, resulting in slowed plant growth and poor fruit set. High levels of "available" P can significantly reduce Zn uptake by the plant. The use of chelated Fe in a nutrient solution can reduce Zn uptake and utilization.
The micro nutrients, when not in their proper concentration range in the growing media or plant, can result in a deficiency or toxicity. Additions of a micro nutrient to the soil should be made based on a soil test and/or plant analysis-based recommendation. Monitoring the micro nutrient concentration in a nutrient solution is important in order to avoid their excess accumulation or deficiency.
Other Essential Nutrients
Sulfur (S), chlorine (Cl), copper (Cu), manganese (Mn), and molybdenum (Mo) are the other essential mineral elements.
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