Several Potential Problems Growing Tomatoes

Problems Growing Tomatoes

Brian Jervis: As A Master Gardener

Tuesday, June 27, 2017

Q: What is wrong with my tomatoes? They were doing OK, but now blossoms are dropping off before I get fruit. Also, some tomatoes are splitting and plants have yellow or curling leaves. Martha H., Tulsa

A: These are all common issues that Oklahoma tomato growers face.

The actual fruit comes from proper pollination of the blossoms, but when successful pollination does not occur, the blossoms die and fall off. This is commonly known as “blossom drop.” Weather is the chief cause of inadequate pollination in garden-grown tomatoes, with the most important factor being temperature.

Effective pollination does not occur once night temperatures are outside the range of 55-70 degrees or if daytime temperatures are consistently higher than 92 degrees, especially if it is windy. Too much rain or too high or low humidity are additional weather factors that reduce pollen fertility. Over application of nitrogen fertilizer also leads to blossom drop, as well as tall, lanky plants.

Tomato fruit splits, rots or develops blemishes for several reasons. The most common cause of tomatoes rotting before they ripen is “blossom end rot,” which is caused by a calcium deficiency in the plant. Overwatering, either from nature or the gardener, is the most common cause, rather than the lack of calcium in the soil.

Skin splitting is also caused by plants going from too little to too much water. Be consistent about watering. Mulch plants to provide consistent moisture at the root level, but do not mulch against the plant itself as it can lead to diseases.

Avoid splashing soil upon the plant and onto tomato fruits, as this carries related fungi and bacterial diseases. Instead, either use a soaker or drip irrigation system or carefully water at the base of the plants. Avoid damaging tender roots by not hoeing too closely to the plants.

There are several reasons that cause yellowing of leaves. It could either be from a small pest called a spider mite, from a fungal leaf disease, or from stress caused from either over or under watering. Check the soil to see if it is overly wet or dry before moving onto the other causes. Just like your lawn, water plants thoroughly (6-8 inches deep) to encourage tomato roots to seek water and nutrients deep in the soil. With an extensive deep root system, the plants will hold up better during dry spells.

Garden tips

·        Mulch ornamentals, vegetables and annuals. This reduces soil crusting, cools soil and conserves moisture during hot summer months. Mulch also helps prevent weeds and reduces likelihood of mechanical damage from lawn equipment. Mulching will reduce about 70 percent of the summer yard maintenance.

·        A disease called “fireblight” is prevalent now. It may infect more than 100 plants in the rose family but especially apples, crabapples, pears, quince and pyracantha. The bacterial disease is spread by insects and rain and enters the plant through open blossoms. Once infected, the leaves on the involved limb turn brown and the limb dies. The only treatment is to remove the dead limbs. An antibiotic spray can be helpful but only during full bloom and only used to prevent the disease. Some trees are more susceptible than others, consideration should be given to planting disease-resistant varieties.