Too Much Shade on Tomatoes Equals No or Poor Fruit

Q. We are growing the Celebrity variety of tomatoes in our garden here in Las Vegas and decided to cover them this year with a mesh tarp for shade because the sun has scorched them in the past.  However, we noticed the vines are growing but the tomatoes are not very big and they are not ripening like they usually do.  Are they supposed to have complete sun? What do you suggest?

Providing too much shade causes poor growth and reduced fruit or flower production or none! 30% shade vs 60% shade.

A. The amount of shade that you provide to tomatoes is critical for continued production of fruit. Shade cloth is typically categorized by the percent of shade that it provides. For flowering plants you should provide no more than 30 to 40% shade or they may stop flowering and setting fruit. Plants that do not flower can handle more shade, up to about 50 or 60%.

            You didn't tell me what percent shade you are giving tomatoes but I suspect it's too much. Light shade, 20 to 40%, is hard to find locally. Usually you have to order light shade for crops. You can provide shade by also using lathe instead of shade cloth.

            In northern climates we used to use snow fence. To get 50% shade, remove every other lathe from a solid ceiling of lathe. To get 25% shade, remove two and leave one. Chain-link fence with PVC slats gives you about 75% shade. I think you get the picture.