Dry and Shoot Weight

• Compost-grown tomatoes experience a decrease in shoot weight and an increase in dry weight. The dry weight is found after drying the plant at 80 degrees Fahrenheit. It helps determine how much cell growth has actually occurred by removing the water content from the equation. Plants fed with a compost tea as a soil drench and as a foliar feed actually grew to twice the size of a plant fed with just water, which would indicate the response is more favorable in liquid form than dry matter.
  
  

Roots

• The American Society of Microbiology conducted a study that included tomatoes grown in gradually increasing levels of compost. The tomatoes that were grown in full compost had a higher rate of roots and root weight. The higher rates of organic matter in the compost affected the nutrient accumulation from the roots, and the plants had a higher amount of nitrogen and potassium.
  
  

Microorganisms

• Tomato plants that grew in high concentrations of compost are less resistant to the common diseases that plague them. Overall, the ability of the plant to defend itself against disease was reduced by almost half. However, the soil itself contained high levels of beneficial microbes. A University of Connecticut study found no difference in the rates of Anthracnose, a common disease, in a tomato plot with compost amendment. However, some reversal of the rate of bacterial disease was found in the composted soils. There is a definite correlation between the compost and microorganisms that stop root pathogens, reports the American Society of Microbiology. The conflicting information in all these reports leads to the conclusion that further study is required.
  
  

Fruit Production

• The University of Connecticut trial also found that compost-amended tomatoes matured faster by three weeks. They also state that compost results in increased yields. Increased compost content was found to enhance the fruit production of tomatoes in a North Carolina State University study on municipal landfill compost. The high nitrogen level of the compost is thought to be the reason as nitrogen encourages fruit set. The use of compost tea in soil drenches and foliar sprays did increase the fruit production of tomato plants significantly.