Last year was very similar up here in the high country, Spring seemed to have broken early with perfect weather in april , prompted me to get the boat running and out there , then may and early june was terrible, cold ,grey, snowy for like 3 weeks straight , this years not as bad as last but real similar , I have kept logs for my veggies (as well as other) for several years here @ over 8000 ft above sea level. Many claim fathers day as the plant date for outdoor up here, but I always shoot for earlier . A few years ago I planted my guerrilla garden outdoors around the third week of may, and had a successful vintage , at just below 9000 ft. Every year is a toss up here though , you gotta be ready early, but be prepared to wait til june if necessary. My tomatoes have endured some cold nights (accidentally) this season. Left my herbs out last night .. F ! basil ,mint , marigold mint, lavender... looking pretty pissed today.
