The unthinkable happened the night before last, just what I was afraid of. Frost. Not just a borderline nibble but a solid 4 degrees below 0 (according to my el cheapo Lee Valley high-low thermometer). But my 5-point strategy of avoiding damage paid off, barely. High-low #2 said the lowest overnight temperature inside the two-layer, sorta-heated low tunnel was just a hair under freezing. No damage to anything. What’s pleasantly surprising is that even the relatively unprotected green beans suffered no fatalities. I didn’t think beans tolerated frost at all. Huh.
The nightly forecast lows recently have been around +2 which, accounting for our cooler micro-climate and the forecasters’ perpetually optimistic forecasting, has been translating into -2 to -4C at our place. I have tripled up the reemay and halved the volume of the low tunnel by cramming our tomato starts and potted zucchinis into 6′ of tunnel instead of 12′. I also put the heater on its high setting which seems to be doing the trick. And the forecasts for the next few days are for 6+C lows, so we should be ok from here on in, with or without precautions.
But stranger things have happened.