Dear 100 Hour Board,
Not sure how well you'll be able to help with this, but it is worth a try. I have a tomato cultivar I am planting in my garden this summer that is native to Italy (Costoluto Genovese) how best should I adapt my care of this plant for Utah's desert. More water? More shade? Different soil nutrients? It is alive so far, but seems rather limp and I'm worried that it is not thriving. Any advice you, or resources you have, could offer on caring for a plant that is in a very different environment than its native habitat would be appreciated!
-My Sort-Of Green Thumb
Dear Green Thumb (Sort-Of),
That sounds so awesome! When I was a kid, my family would grow tomatoes during the summer and they were wonderful. This was in Southern Utah, so I understand your problem in some ways. Our plants definitely struggled to grow in the desert environment. Keep in mind, though, that I'm not exactly a gardening expert and that you should possibly couple this advice with your own research.
Utah's climate is very different from Italy. Most gardening resources suggest considering a tomato variety more accustomed to the heat, but in this case, your best bet is to adapt the environment around the tomatoes rather than re-plant. The suggested temperature to raise Costoluto Genovese tomatoes in is around 60F, which is about 20 degrees lower than the current temperature in Utah. This could be part of the reason your tomato plant is limp. More shade could be a good idea if you can find a spot with lots of shade in the afternoon.
For tomatoes in especially hot weather, it's a good idea to make sure they get lots of sun in the morning but shade through the afternoon. If you do not have a place in your garden with natural shade, artificially construct it. If you create a shaded structure that's open to the east, your tomatoes will get sun in the morning and shade in the afternoon. Construct a frame around the tomatoes, then drape a shade cloth (found at gardening centers) over the frame. Many resources suggest a "50 percent" shade cloth, which will reduce heat by that percentage.
Some resources also suggest adding a mulch layer (2-3 inches) around your tomatoes to keep the soil damp. You can buy bagged mulch or create your own. Stick your finger into the soil around the tomatoes to assess wetness. If the soil is dry, your tomato isn't getting enough water. Keeping the soil moist constantly can prevent limpness, so be sure to water your plants daily or even twice daily depending on how hot it is outside. Also, avoid over-fertilizing your tomatoes on especially hot days (over 85F for most tomatoes, but maybe 75-80F for Costoluto Genovese tomatoes), because this can overstress the plant.
Good luck! I hope your tomatoes turn out okay. Let us know if you have more questions.