Every gardener that I talk to in the mid-Atlantic region is singing the same refrain “This has been the worst year for tomatoes that I can remember”. I second that!
Heat and humidity has hit us hard with extended periods of over 95 degree weather and the tomatoes are hating it. Climate change? Yes, the last month of July 2016 was the hottest on record according to NOAA dating back to when record keeping started in 1880. The average temperature for the globe was 0.87 degrees Celsius above the 20th century average. Go to State of the Climate from NOAA to see the statistics. There were 15 days of record-breaking heat in July. This is not good news for Tomato Central, the Mid-Atlantic region where I live.
According to Bonnie Plants, “Sizzling summer temperatures can bring your previously productive tomato plants to a screeching halt. When days hit 85°F to 90°F and nights hover above 75°F, tomato flowers often fail to pollinate, then drop — which in turn puts new fruit production on hold. The longer the heat lasts, the longer those tomato flowers will continue to hit the pause button. In short, hot weather can delay your tomato crop”. Tomatoes do not need bees to pollinate. They are wind-pollinated.
I am usually canning like crazy and making tomato sauce but that hasn’t happened this summer. I had a few times where I picked a large basket of tomatoes, but nothing like previous years when my kitchen counters are groaning under the weight of ripening tomatoes with my 20+ plants.
Tomato plants thrive in balmy sunny summer weather, but overly high temperatures stress the plant and slow production. Prolonged temperatures above 95 degrees cause water stress, fruit damage from sun scald and slow ripening. One of the few bright spots were my dwarf tomatoes that seemed to hold up better than the full size ones. I had two dwarfs that sizzled, but four of them did very well. Check out my post on Dwarf Tomatoes. I will be planting more dwarfs next year. Taking much less room and easier to care for, I really enjoyed growing these for the smaller plants but full-sized tomatoes.
So, what is a gardener to do?
Plant heat tolerant varieties like Heatmaster, Solar Fire, Summer Set, Florida 91, and Phoenix. These set fruit even when the heat climbs up to code red days.
Mulch, mulch, mulch-This keeps the soil cooler by insulating the ground.
Keep some shade on the tomatoes, especially in the scorching afternoon. Shade cloth covering row cover hoops works well.
Stop fertilizing so the plant is not putting all its strength into new growth when stressed.
Water-Any plant can handle heat better if it is well watered.
Pick early and often. When temps consistently hit the 95-degree range, tomatoes tend to stop producing red pigments, which means typically red fruits may instead ripen to orange. I had this problem. I thought that I made a mistake and planted all orange tomatoes. Fruit left on plants may have some color on the outside, but may still be green inside. Pick any fruit already showing hints of ripe color and allow it to finish ripening indoors.