When plant nutrients are in great excess or extreme deficiency, the symptoms on the foliage or in some other plant part generally reveal themselves to the naked eye. Such plants look “sick.”
However, growth and productivity are considerably reduced before definite symptoms are noticed.
Be cautious, we suggest, before placing any blame for the condition.
The causes of poor growth are often rather complex and cannot always be readily traced to a lack or excess of a single factor or plant-food nutrient.
Factors Producing Similar Signs Of Plant-Food Deficiencies
Freezing temperature, hot winds, drought, and mechanical injury sometimes produce effects comparable to plant-food deficiencies.
Insects and seed or soil-borne diseases may disturb the plant’s internal functioning enough to make it deficient in some plant-food nutrients.
Severe damage to the roots by larvae of various insects, or intensive feeding of minute insects on the foliage cause plant reactions that sometimes are difficult to distinguish from mineral deficiency symptoms.
Occasionally, poor growth can be traced to large tree roots, a leaky gas main, too much shade, particularly in the morning, or a subsoil drainage problem.
Correct diagnosis of trouble is not easy, and it can cause many headaches.
Using Starter Solution For A Vigorous Start
Using a starter solution high in phosphorus (one ounce of 10-10-10 or 10-52-17 to a gallon of water) at the rate of a ½ pint per plant will generally give tomatoes and peppers a vigorous start.
Effects Of Nitrogen Application To Plants
Over-fertilization with nitrogen frequently delays fruit setting in mid-season or late varieties and stimulates the development of large, poor-producing, bushy plants.
Periods of low night temperatures, below 55° to 60° degrees Fahrenheit, or high day temperatures, above 95° degrees Fahrenheit, also frequently cause blossoms to drop in peppers and tomatoes.
However, in the early tomato varieties that produce many flowers, nitrogen is needed to stimulate plant development.
A fertilizer containing no nitrogen and equal proportions of phosphorus and potassium (0-14-14, for example) on well-manured or heavily fertilized gardens or low nitrogen (3-12-12 or a 5-10-5) ratio on other soils is generally well suited to both tomatoes and peppers.
A two to three pounds broadcast application is generally sufficient.
Applications of ¼ to ½ pound of additional nitrogen material will benefit early varieties after they have become established and may be applied to later varieties, if needed, after the first two or three clusters of flowers have set some fruits.
The general vigor of the plants is a safe guide in determining the need for this application of nitrogen.
Good Soil Condition For Excellent Growth
On deep soils of good physical structure, the fruits of most varieties generally will be smooth and free from cracks or rotten areas on the blossom end.
A well-aerated soil promotes deep rooting, enabling the plant to obtain an even, regular water supply.
Due to over-fertilization with nitrogen or a hard subsurface soil condition, large plants with small root systems frequently produce cracked or blossom-end rotted fruits.
Mulching And Staking
Mulching helps maintain the desired uniform soil moisture supply.
This practice especially benefits staked tomatoes. On soils too high in nitrogen, hoeing in a straw mulch will utilize some excess nitrogen.
Marked Deficiency Signs
Purple or bluish tints in tomato foliage on dwarfed or spindly plants generally indicate a deficiency of phosphorous, although cold weather may give the same discoloration.
A marked deficiency in available potassium may cause a dark green, stunted plant and uneven fruit ripening—hot sun at high temperatures yellows fruits on the exposed side.
Magnesium deficiency is somewhat common with tomatoes.
Applying 30 to 40 pounds of ground dolomitic limestone to every 1,000 square feet of space intended for tomatoes usually will avoid this trouble.