Plant science for plant people.

The bacteria that let you cut fertilizer by a quarter were already sitting on your tomato leaves. Researchers swabbed the leaf surfaces of tomato and eggplant across two growing regions and pulled out 14 strains tough enough to shrug off drought-like stress.

Two earned their keep. Bacillus stercoris KBL91, sprayed on the leaves alongside only 75% of the recommended fertilizer dose, doubled root biomass and pushed nutrient use efficiency above 100% for every major nutrient, peaking at 159.43% for potassium. The plants got more out of less. A second strain, Bacillus subtilis VBR72, knocked back Phytophthora infestans by 87.44%, the late blight that turns a wet August into a compost heap.

Leaf spray isn't the only delivery route getting tested on tomatoes. A six-bacteria mix applied to seed, roots, and soil produced 3.72 kg of fruit per plant in liquid form against 3.1 kg as a powder, and the liquid stayed alive on the shelf past a year. In harsher ground, a fungus found living inside the roots of the desert shrub Ziziphus lotus grew okra 28.9% taller in salty, cadmium-laced soil and more than tripled its shoot weight.

We've spent decades feeding soil and treating leaves as surfaces to spray things onto. The leaf is habitat, and some of its residents were already doing part of the job for free.