As far as us gardeners are concerned, few pleasures in life compare to biting into that first sun-ripened tomato. After getting off to a rather dry start and needing supplemental watering, many of us found our gardens more on the too wet side and wishing some of that rain would go to California where it is really needed. I even found some slugs crawling up the tomato stakes instead of hiding beneath the mulch! Apparently, even they were looking for higher ground!

standing wtr around raised beds

Standing water around raised tomato beds. Photo by dmp.

Vegetable gardeners in New England know that tomatoes face several diseases including blights, leaf spots, anthracnose and so on. We deal with this problem in different ways. I try to grow some disease resistant cultivars, like ‘Peron’ and ‘Defiant’. Both are reported to be resistant to several diseases with ‘Defiant’ touted as having late blight resistance. Having resistance does not mean the plants will not get a disease; just that it often won’t kill them (or at least won’t kill them as quickly!). ‘Defiant’ gets some early blight, leaf spots but typically if I continue removing the infected foliage on a weekly basis; it grows out of them and produces well into the fall. The rainy weather has curtailed some of my weekly clean ups so all my tomato plants look a little worse for the wear.

tomato row w hardly any leaves

Tomatoes with few healthy leaves due to disease/wet weather. Photo by dmp.

There are lots of mid-sized and tasty tomatoes on ‘Defiant’ right now but almost all of them have a condition known as yellow shoulder. This is a physiological disorder and while the affected portions of the tomato are showing up yellow on my tomatoes, they may be green, white, or grey on other varieties. These areas are also tougher and not as palatable. The specific cause for this disorder is not known but it is believed to be related to high temperatures, which we certainly were experiencing, lack of potassium, high soil pH and/or perhaps too much magnesium relative to calcium in the soil

tomato yellow shoulders

Defiant tomatoes with yellow shoulder. Photo by dmp.

It’s always fun to try a new tomato variety or two and this year I planted ‘Tasmanian Chocolate’, a unique dwarf with full-sized, 8 to 10 ounce, mahogany red tomatoes on plants about 40 inches tall. The tomatoes are slightly lobed and delicious, but right now all the fruits are terribly cat-faced. This is another physiological condition where the exact cause hasn’t yet been pinpointed. Supposedly, it starts in the early stages of flower bud development. This disorder has been attributed to low temperatures (below 60 F, which I have not experienced), high amounts of nitrogen in the soil and excessive pruning. If anything, any nitrogen in the organic fertilizer I applied around Memorial Day has been washed out with all the rain and mostly I have just been pruning out diseased leaves Herbicide damage was also given as a potential cause but I have woods on two sides of the property and my next-door neighbor has not applied any. I will try this tomato variety again as it is very tasty and does not seem as prone to leaf diseases as some other tomato varieties.

Tomato catface 2

Catfaced Tasmanian Chocolate tomatoes. Photo by dmp.

Then there is ‘Ildi’, a yellow cherry tomato. I like to grow one yellow, one orange and one red cherry tomato mostly because they look so lovely in salads. ‘Sun Gold’ is my go to orange cherry with its exquisite flavor and prolific production. For a red, this year I grew ‘Matt’s Wild Cherry’, which has oodles of half-inch, tasty red tomatoes.

yel jel bean, sungold sw mill, Fair Blue

Cherry tomatoes – Sungold, Sweet Million, Yellow Jelly Bean and Fair Blue. Photo by dmp.

‘Yellow Pear’ had been an old yellow cherry tomato standby and even though it did not crack that easily and outgrew most disease problems, the flavor was rather bland. So, I tried ‘Ildi’ last year and was happy with the flavor and decided to grow this variety again this season. Huge clusters of flowers had formed and I was all ready to enjoy hordes of yellow, sweet tomatoes when I noticed almost all the flowers aborted and only 4 or 5 tomatoes managed to mature per cluster. I believe this is due to the heat we’ve had over the last few weeks and perhaps also lack of pollination due to cloudy, wet weather. Tomatoes are self-fertile but wind and bees do help.

Tomato Ildi aborted blossoms

Only 3 tomatoes in this cluster of ‘Ildi’. Photo by dmp.

Despite the weather and some creature that has been stealing a tomato or two, there are still plenty of tomatoes to be had for fresh eating and for sharing. They say the average American eats about 20 pounds of fresh tomatoes each year. I’m trying to do my part using huge, thick slices of ‘Amish Gold’ for my BLTs.

Tomato Amish Gold BLT

BLT with tomato ‘Amish Gold’. Yumm! Photo by dmp.

Good gardening to all,

Dawn

August is supposed to be the month of non-stop tomatoes. Occasionally things go awry to interrupt those carefully laid spring visions of bountiful harvests, sauce making, and endless tomato sandwiches. Blossom end rot can appear to put an end to the crop production by damaging the ripening and developing fruits. We are seeing and receiving calls in a  higher number than more recent years from backyard gardeners complaining about black rotten spots on the bottom of their tomatoes. The spots start as a thickened, leathery spot which sinks in, always on the bottom of the fruit.

Blossom end rot on tomato, ohioline.osu.edu

Blossom end rot on tomato, ohioline.osu.edu

Blossom end rot can also occur on peppers.

Blossom end rot on peppers, photo taken by client

Blossom end rot on peppers, photo taken by client

Blossom end rot is a physiological condition due to lack of calcium. Calcium is needed by plants for  proper growth in all functions of cell making, but is most important for cell walls. Without enough calcium either in the soil, or if delivery of uptake of dissolved calcium in soil water is interrupted, cell division stops in the fruit. Tomatoes are especially sensitive to a lack of calcium.

Interruptions in uptake of calcium can happen by repeated cycles of soil drying out, receiving water, then drying out again. Times of drought and hot, humid weather make the problem worse. Plants lose water through their leaves through a process called transpiration, similar to the way we sweat. They then pull up water through their roots. If there is not enough soil moisture, plants wilt. This break is water delivery also limits calcium delivery. Tomato, and to a lesser degree pepper fruits, respond by developing rot on the bottom, the end where the blossom was before the fruit started growing.

High humidity and multiple cloudy days reduces transpiration, thereby reducing water uptake. This leaves plants not able to bring up new calcium rich water to the site making new cells of the fruit. Another interruption of delivery of calcium resulting in blossom end rot. This means that even if you have enough calcium in the soil and you water the soil regularly, the plants still may not be able to move enough calcium to where it is needed to produce a fruit.

Have a soil test done to make sure soil has enough calcium and that pH levels are around 6.5 so nutrients are most readily available. Water regularly so plants receive 1 to 2 inches of water per week for optimum growth. Feel the soil around the root zone to make sure water is soaking in and reaching the roots. Humidity and cloud cover are not obstacles we can help the plant with, so monitor the fruit for rot spots and remove. There are calcium foliar sprays which claim to deliver calcium to be absorbed by the leaves for use by the plant. This won’t help after the rot has already developed, but may help deter future spots on still developing tomatoes.

-Carol Quish