This is one of my limes at a friend’s house in Maine.
But it’s feeling very cold here in Oakland even. Frost warnings at night. What’s a citrus farmer supposed to do? Wrap my trees, that’s what. Whenever I hear the temps will be in the low 30s, I drape the citrus trees with floating row cover aka Agribon aka Remay. This acts like a jacket for the tree–the spun poly fibers raise the temperature around the tree by almost 5 degrees.
Now, the other thing to do is to spray the plant with water. To us mammals, this sounds like an insane survival strategy. To understand how it works note that water has three phases: ice, water, and stream. To get ice to melt takes energy, just like it takes energy to make water boil. When water is going through a phase change, energy is given off. As water freezes into ice, heat is actually given off. A hydrated plant then, will be a warmer plant. If you love ‘em, cover ‘em.
Speaking of fruit, the Golden Gate chapter of the scion exchange is happening this weekend! Saturday, 12-3 at Ed Roberts Campus in Berkeley by the Ashby BART. http://www.crfg.org/chapters/golden_gate/scionex.htm. If you’ve never been, get ready for a fruit-seeking thrill like no other.