“If you’re going to mess up a crop, it’s tomatoes. They’re like the canary in the coal mine.”
Those were the opening words of Steve Bogash, regional horticultural educator at Penn State University, to a roomful of growers at the Ohio Produce Growers & Marketers Association Congress in January.
Bogash has produced more than 300 tomato varieties in trials. In spite of his opening comments, Bogash has met with many successes in tomato production and said that one of the best varieties he has worked with is BrandyBoy from Burpee Seeds.
“The flavor of this tomato is tremendous,” he said. In addition, “Rather than getting three to five fruit before disease sets in, as is the case with the variety’s parent, BrandyWine, BrandyBoy is a hybrid that produces a lot of tomatoes long term, due to high resistance qualities and the ability to grow multiple fruit per cluster.”
Those successes are not without difficulties, however, as blossom end rot, yellow shoulders, uneven ripening, and radial cracking have occurred on Brandyboy and any tomato that does not receive proper nutrition.
Planning for Success
In order to maximize success producing virtually any variety of tomato, Bogash presented some guidelines growers should follow.
1). First, he said, is to use varieties with disease-resistant qualities. Bogash has had success with BHN 589 (BHN Seed Co.), Scarlet Red (Harris Moran Seed Co.), and the previously mentioned BrandyBoy. Noting that there are many other good tomatoes on the market, Bogash said these varieties are the ones that he has had the most success with to date.
2). Growers should also be aware of what to test and when. “You have to test regularly,” he emphasized, “and know your soil or potting media.”
Bogash told the audience to test soil before planting, again at the onset of heavy flowering, and a final time at the first and second stage of green fruit. Testing at all stages of growth is necessary to monitor nutrient removal.
“Tissue testing should also be done at the onset of flowering and every two weeks thereafter in order to monitor nutrient uptake,” he explained. This will help growers understand how to adjust their fertility programs to ensure optimal growth.
Growers should then continue testing every two weeks until the last fruit has sized up. When taking tissue tests, Bogash said growers should be sure to test the correct plant parts. These include collecting 12 to 15 of the most recently mature leaves including the petiole. He emphasized that samples should also be of average plants as opposed to small or large ones.
Another thing to remember, Bogash stated, is to be consistent in time of day you are collecting and weather conditions. “This matters because plants photosynthesis levels vary with sunlight levels and temperature,” he explained. Working with a lab with less than a four-day turnaround on results will also help, he added.
3). Growers should also test their soil and apply plow down nutrients to 30% to 50% of soil test recommendations. Plow down nutrients are applied to the soil and then plowed under. “You need to begin with good nutrient levels as it is very challenging to fertigate everything that plants need if the soil is deficient,” he explained.
4). Growers also need to know their water’s pH level, alkalinity, nitrogen (N), phosphorus (P), and potassium (K) levels. “Water pH and alkalinity are the most important as they directly impact nutrient uptake,” said Bogash. “N, P, and K levels can be important if there are significant levels as they impact nutrient application levels, and, if too high, can stimulate algae blooms which can clog drip irrigation systems.”
In addition, growers should be aware of the difference between well water, spring water, and the water that comes from a stream or a pond as these natural sources of water are exposed to the elements and thus change at a much more rapid pace than other water supplies.
5). As the results of the tests come in, growers should plot the changes in N, K, and P, as well as calcium (Ca) and magnesium (Mg) over the course of the season. Growers should also adjust the program as necessary to keep key nutrients up to specs, Bogash said. The ideal amounts from flowering onward include levels of N around 4%, K at a little more than 3%, P at 1%, Ca at 3%, and Mg at .8 to 1%.
High N can aggravate a yellow shoulder problem and make soft fruit, he warned. Low K at flower fertilization will cause yellow shoulder. Growers should use high K fertilizers along with foliar applications and supplementary Ca, Mg, and P as needed based on tissue testing, he added.
6). Ripening is the next phase. Tomato fruit contain substantial amounts of potassium, since potassium ions are responsible for water movement across membranes. Therefore, growers need to make sure there’s plenty of it be-cause if it is short supply, plants cannot move carbohydrates and other molecules as needed.
“Potassium is very important for sugar movement, so without good management, the flavor will suffer,” he concluded.