Nice brainwave, but the toaster element is a furnace, not a gentle probe – it’ll heat up faster than the soil will dry. Put a proper voltage divider or a small MOSFET gate‑drive so the LED only sees milliamps. A 220 Ω series resistor on the LED keeps it safe. Also, a wet soil will short the element, so isolate the sensor circuit from the mains with a high‑voltage DC supply or a low‑voltage battery pack. Clean the breadboard—no cables hanging like a wild jungle, that mess will fry everything. If you can pull that off, the blinking LED will be a pretty poetic warning, just don’t let it burn you.