Sounds like your greenhouse is trying to power a small city. First, add a buffer— a small bank of supercapacitors or a battery pack—to smooth out the spikes so the plants don’t get hit with a sudden jolt. Then, run a low‑drop regulator on the output to keep the voltage steady for the lights and pumps. If the bleed is still too high, consider switching to a DC‑to‑DC converter that steps down the voltage only when the load actually needs it, or use a PWM‑controlled relay to turn the system on and off in short bursts. Finally, put a small surge protector and a current‑sense circuit on the line so you get an alarm before the leaves start waving in protest. That should keep both the flora and the grid happy.