Plant Nutrition

Blossom-end rot on greenhouse tomatoes

This photo was submitted by a grower. Blossom-end rot is a due to lack of calcium in the fruit. The blossom end of the fruit develops brown to black, dry, sunken, leathery areas.

Prevent blossom-end rot by providing proper calcium level in the growing media, avoid uneven watering and avoid allowing plants to wilt. Plants also need healthy roots for calcium uptake.

Resources for growing greenhouse tomatoes

Salt injury on pansies due to excess sodium and chloride in irrigation water

Salt used for deicing roadways in winter can be phytotoxic to plants. When salt dissolves in water, sodium and chloride ions separate. The roots readily absorb chloride ions and they accumulate to toxic levels in the leaf margins and shoots tips. This toxic build-up results in a characteristic marginal scorch. Symptoms of sodium toxicity are marginal leaf chlorosis followed by marginal necrosis. Pansies are particularly sensitive to salts. Other highly sensitive crops are fibrous begonia, celosia, impatiens and zinnia.

Fertilizing Herbs

Over-fertilizing herbs in containers for spring sale is a common problem this time of year. Compared to most bedding plants, herbs are lite-feeders. When the herbs are mixed with bedding plants in a greenhouse the tendency is to fertilize all plants at one rate. Try to avoid this practice.

A standard recommendation for most herbs is 100 to 150 ppm nitrogen (constant liquid feed). A routine clear watering is a good practice if the soil mix is allowed to dry.

For more information on growing herbs:

pH and Fertility Requirements of Spring Annuals

Providing the proper combination of pH and fertility levels for spring annuals can be quite a challenge for growers used to the traditional "one-size-fits-all" approach to fertilizing bedding plants and pH management. The summary below organizes the pH and fertility requirements of widely grown seed- and vegetatively-propagated annuals using recent BallFloraPlant®, EuroAmericanTM, and Proven Winners® catalogs. The plant culture sections of these catalogs are in very close agreement on the pH and fertility requirements for almost all of the species.


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