How does lemon water affect plant growth?
I can see two effects, if it is potent enough the acid could burn the roots of the plant causing stunted growth or death, similar to what happens if you overfertilise. What’s more likely to happen though is that the acidic juice will alter the soil pH and cause certain nutrients to become ‘locked up’ and unavailable to the plant. Usually the symptoms of mineral deficiency are yellowing leaves, stunted growth, general poor performance. Different plants have different pH requirements so the effect on the plant would differ depending on how tolerant the plant is of acid soils.