Plant Nutrition

Greenhouse tomatoes - Blossom end rot

Recently a grower sent photos of a problem he was having with his greenhouse tomatoes. While this problem occurred on greenhouse tomatoes, it can also occur on tomatoes grown in home gardens and fields.

Blossom-end rot on greenhouse tomatoes is a condition caused by a lack of calcium in the fruit. The blossom end of the fruit develops brown to black, dry, sunken, leathery areas.

Fertilizing Bedding Plant Seedlings

Fertility is an important factor in the production of high quality seedlings by the plug method or traditional row or broadcast methods. Recent research has shown that fertilization must begin shortly after germination and that abnormal seedling growth is often caused by nutrient disorders. The success of a fertilizer program for bedding plant seedlings and transplants is determined by more than just the rate (ppm) of fertilizer applied. Other factors which are as important as rate include fertilizer type (NPK analysis, micronutrient package, proportion of ammonium (NH4) vs.

May Pest Message

Pest Message, Week of May 1, 2012

Here is what is happening in greenhouses, courtesy of Jim Mussoni, IPM Consultant, Leanne Pundt, UConn, Tina Smith, UMass and Bess Dicklow, UMass Diagnostic Laboratory

New Guinea Impatiens - Twisted leaves

Twisted growth can be caused by physiological or nutritional disorders, broad mites or ethylene.

New Guinea impatiens may exhibit twisted foliage and edge burn as a result of high soluble salts. Cupping and wavy leaves also appear to be favored by dry soil and cool moist air. These symptoms commonly show up in March and April and usually disappear as weather improves later in spring. Orange cultivars appear to be prone to this condition and have exhibited these symptoms in early spring.

Uneven Transplants

This photo shows uneven distribution of controlled release fertilizer prills in 72 size cells used for growing vegetable transplants for the field. One cell had 2 prills, another had 7 or more prills. Controlled release fertilizers pre-mixed in the growing media can cause uneven growth if the fertilizer prills are not uniformly distributed between the cells. Growers should work with their media suppliers to match the proper growing media with the cell size being used. Growers can count the prills in the individual cells to determine the accuracy of the distribution of prills.

Soluble salt injury on pansies

These pansies were first thought to be nutrient deficient due to the light green color of the foliage. An electrical conductivity (EC) test revealed high soluble salts. High growing medium EC can injure or inhibit the growth of plants. Common causes of high EC include: excess fertilizer (too high level or too frequent application), subirrigation, root disease, or restricted drainage. A soil test is almost always needed to confirm a soluble salts problem.

Soluble salt injury on geranium root

Notice damaged, dark colored roots on this geranium. Combination of controlled release fertilizer (see prills at top left of roots) and liquid fertilizer contributed to high soluble salts. Roots are just beginning to regrow after plants have been leached. These symptoms could also be caused by Pythium root rot. In many cases, injured geranium roots also have Pythium.

Soluble salt injury on geranium

The symptoms on this geranium suggested wilt disease or micronutrient toxicity due to the spotting and foliage edge burn. An electrical conductivity (EC) test revealed high soluble salts. High growing medium EC can injure or inhibit the growth of plants. Common causes of high EC include: excess fertilizer (too high level or too frequent application), subirrigation, root disease, or restricted drainage. A soil test is almost always needed to confirm a soluble salts problem.

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