Want to improve tomato crop yields without using more fertilizer? Try  verimcompost leachate. That is a soil ameliorant, which is basically a fertilizer but made of an organic liquid produced by earthworm poop. If you are really organic, you can even make tea from it. 

A research project recently studied the effects of vermicompost leachate on tomato seedlings subjected to various temperatures and levels of water stress. 

To investigate temperature stress, potted tomato seedlings were exposed to temperatures of 10, 15, 20, 25, and 30 °C and treated with and without vermicompost leachate (1:10 v/v). The experiments of water stress involved established tomato seedlings treated with and without
vermicompost leachate
(1:10 v/v) treated with varying volumes (15, 30, and 45 mL) of half-strength nutrient solution.  

They dilute it to 1:10 because it is still a chemical. And from a food safety perspective, avoid applying it to leafy greens and lettuces because it's still worm poop when you get right down to it.

"Most of the morphological parameters of
vermicompost leachate
-treated tomato seedlings were not only markedly enhanced at optimum temperature (25 °C), but also exhibited significant improvement under high temperature (30 °C)," the researchers wrote. "At lower temperatures (10, 15, and 20 °C), although
vermicompost leachate
promoted several growth parameters of a tomato seedling, this improvement did not differ significantly with the respective controls."

The water stress experiments showed that photosynthetic pigments and compatible solute contents were significantly reduced in VCL-treated tomato seedlings at 15 mL. "Physiological parameters were reduced within the range of those found in more favorable conditions as observed for 30-mL supply of nutrient solution," the authors noted. The scientists said that the results of these water stress experiments clearly demonstrate the possibility of using less water resources to produce quality crops.

The results also showed that the constant supply of VCL improved morphological characters, including leaf area and shoot/root biomass, enabling VCL-treated tomato seedlings to perform better.

The scientists concluded that vermicompost-leachate is a suitable soil amendment alternative that can significantly improve overall crop performance of tomato seedlings under abiotic stresses. "More importantly, VCL is organic and therefore can be used as an environment-friendly fertilizer supplement," they added.