PEAS Farm: Tomatoes taking the heat

This summer at the PEAS farm, the staff has been noticing some changes due to the sustained higher temperatures that we’ve experienced over the summer.  Comments about climate change and how eventually we will need to “Farm like we live in Arizona or move up to the Yukon so we don’t have to change” were rampant.  It’s true, climate change significantly affects the way we can farm in Montana.  There is a difference between weather and climate that our State Climatologist Dr. Kelsey Jencso of the University of Montana describes well:

The difference between weather and climate is a measure of time. To understand climate at a given place requires synthesizing the variation in weather over relatively long periods of time. Weather is the day-to-day interaction of factors like temperature, humidity, precipitation, cloudiness, visibility, and wind. Scientists pursue an understanding of climate trends or cycles of variability and place those phenomena into the bigger picture of possible longer term changes in our climate.

The warmer weather can help with some plants and hinder others, but even heat-loving plants like tomatoes, peppers, and eggplants have a limit to what they can take.  A number of studies (just Google it!) have shown that high temperatures during flower blooms can inhibit pollen fertilization.  Flower fertilization is what gives us many of the fruits and vegetables we love; a few examples are zucchini, strawberries, corn, and tomatoes.  Let’s stick with tomatoes for a minute.

This week we picked the sweetest, swear-it-was-an-heirloom outdoor tomato that our staff farmers have ever tasted.  I’ll admit, a few of us are a bit snobby about tomatoes and really stick with the heirloom varieties, but this tomato might convert those who generally snub the field-grown tomatoes.  I’ll share this new special variety with you, it was a Bobcat tomato.  Recommended to PEAS Farm Director Josh Slotnick by his wife Kim Murchison of Clark Fork Organics, this tomato shocked and awed our taste buds.  Even two little PEAS day campers, the daughters of Biga Pizza owner Bob Marshall, told us it was the most delicious they had ever tasted and they were going to have their dad get Bobcats for the restaurant.  

The Bobcat is a good variety, but it has also benefited from warmer than average temperatures.  The warmth means that our tomatoes have gotten to be big plants quickly.  This is great, because we’ll likely get more tomatoes from our large and healthful plants.  This is also only great if it doesn’t stay so hot.  Above 90 degrees Fahrenheit, tomatoes start to feel the heat.  The flowers of the plant might start dropping off and the tomato fruit can get sunburned, which looks like big tan spots on our tasty Bobcats.  All plants have an optimum temperature range, just try growing spinach in the middle of summer and notice your lack of success.

I have no soap box to stand on about climate change, particularly since this blog’s readers are likely already eating locally and sustainably grown veggies in their CSA shares.  It’s just something to think about for our food future and something I am noticing as a young farmer learning from older farmers in Montana.  Perhaps it is especially important here in our dry region where irrigation is needed and water supplies are limited.  For more information about Montana and climate change, check out the National Center for Appropriate Technology while you enjoy a sweet tomato.  If you are looking for even more on this topic, check out this New York Times editorial by local foodie Gary Nabhan from last month.