Few homegrown vegetable crops are as eagerly anticipated as fresh, ripe tomatoes, and for good reason!

I have never tasted a supermarket, hot house, greenhouse, or any other commercial tomato that even comes close to the flavor of a homegrown, ripe tomato. As a kid growing up in Jersey City, NJ, we bought “hard ripe Jersey tomatoes” from a street vendor, who sold them from his horsedrawn wagon as he chanted the previous refrain over and over. (Yes, I am that old!) Jersey tomatoes helped make the “Garden State” famous for its produce.

Today lots of produce is still grown in southern New Jersey, but most of the spine of the most densely populated state in America, along the New Jersey turnpike, is far too urbanized to allow farming. That is a pity.

Sadly, the best land for agriculture is also the best land for housing and industrial development. Flat land, well-drained soils, proximity to transportation alleys and major areas of commerce have pushed many farms out of business. In Canada, the best agricultural land is protected from such development. Farms must remain farms and development is prohibited without serious tax consequences. This is partly why you see so much produce in your local supermarket being grown in Canada.

With the huge increase in backyard gardening I have observed in this COVID climate, I imagine lots of local people are growing tomatoes for the first time. In general, first time crops in “virgin” soil do quite well under such conditions, but by this time of the growing season, pest problems do begin to appear.

Last week I mentioned “blossom end rot,” or BER, as a common problem that shows up just as those first, eagerly anticipated fruit begin to ripen. As I often mention, it is much easier to prevent pest and other problems than it is to cure or rectify them once they occur. Since BER cannot be cured once it occurs, I will elaborate on the disorder.

Blossom end rot is caused by a lack of calcium in the plant, but most of the time, that is not due to a lack of calcium in the soil. Early in the season tomato plants tend to grow lots of leaves. This is especially true when there is excess nitrogen applied as is often the case with backyard gardens.

Fertilizer is cheap and many think if a pound is good, then 10 pounds is better! This is not true, of course. It is just the opposite. Excessive nitrogen fertilizer sometimes prevents fruit from forming or ripening until very late in the season. I often hear of eight foot tall plants that have no ripe fruit in September even.

Plants sold at garden centers in cell packs or even in individual pots usually have tops that are five times or more larger than the roots. They look nice, and these are the ones that shoppers prefer to buy, but in reality, they are totally out of proportion to what a “normal” transplant should look like. The root system of a normal, healthy, plant is about as big as the top growth, or even bigger. The plants will continue to grow leaves in their container, as long as they are kept well-watered and fertilized, but once they start to flower and set fruit, the roots cannot absorb enough calcium from the soil to allow the fruit to develop normally.

Calcium is not actively or selectively absorbed as is nitrogen, or phosphorus, or potassium. It is passively absorbed in the water that the roots absorb. As the season progresses, the root system expands and is able to absorb enough calcium, but by that time, the developing fruit ends up “donating” some of its calcium to the rest of the plant. That produces the black spot on the bottom of the tomato. Blossom end rot almost always “cures” itself later in the season as root systems expand. Root growth is directly influenced by soil temperature. Cool soil still allows for top growth, but roots grow much slower when the soil is colder.

Research has demonstrated that yields of tomatoes are much higher when small transplants, with only two or three sets of true leaves, are set in the ground and when the soil is 70 degrees or higher.

Human nature tells us we want quick results, so we tend to set out the biggest transplants we can buy, as early as possible. This may result in some earlier harvest, but in the long run, yields will be greatly reduced. Home gardeners who start their own transplants from seed should wait until mid-April to sow tomato seed. It takes about six weeks to grow an optimal-sized tomato transplant, which allows for transplanting in late May to early June when soils have warmed to 70 degrees. Some of us, who garden at higher elevations, do not set out our tomatoes until mid-June.

Reach Bob Beyfuss at rlb14@cornell.edu.

Johnson Newspapers 7.1


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