When growing non-native plants in Phoenix, the first “protection” that used to come to my mind was from the sun in the summer. After starting some tropicals this past fall, I’m now equally concerned about frost/cold protection.
We had an impressive freeze right before Christmas in South Gilbert, dipping down into the twenties. For a mango tree, that could spell doom. Unfortunately, our first round of frost protection was very lacking. We sort of just pushed some stakes in the ground and wrapped some too-thing plastic around the whole thing. You know that relative that is terrible at wrapping Christmas presents? This was worse. And three of our four mangoes paid for it.
Since then, we’ve constructed much more sturdy structures using PVC pipe and three-way elbows (see image below). The elbows are around $1.50 each at Lowe’s. There are basically four vertical pieces and four horizontal pieces connected by these elbows. The vertical PVC sections are held in place by 3′ rebar that is driven into the ground. I built the structure first, eye-balling the size based on each tree, set it in place, then marked where each piece of rebar needed to go. This ensured that it was relatively square and did not require me to measure everything perfectly.
We used 2Mil painters plastic (but some recommend up to 6mil) to wrap the outer edges and queen size fitted sheets from Goodwill (less than $10 each) for the top. It is important to let the tree “breath” so I didn’t want to cover the entire thing in plastic. This was also an insurance policy for days when I forgot or honestly didn’t have time to remove the tops during the day. It is important that the plastic drapes on the ground to ensure the cold air does not simply slip under and into the structure around your tree/plant.
We secured the plastic and top sheet in place using clamps. I found what I believe to be a killer deal on good quality clips on Amazon, here. They have nice handles and the grip/clamp part does not tear the plastic.
The other consideration is a heat source for particularly cold nights. We found these simple aluminum clip lights on Amazon for around $8 each and used these ceramic heat bulbs as a heat source. I like that these are specifically for heat and do not emit light.
We ended up using two heat lamp setups per tree. I clipped them to a wooden stake in the ground, positioned closely to the lower part of the trunk since heat rises.
What I also like about this setup is we will use these PVC structures for shade cloth during the hottest days of summer. I will need to paint all of the exposed PVC with latex paint to protect it from the sun. UV rays make the PVC brittle and prone to breaking.
We also invested in a handy set of temperature sensors. It was only about $70 and has five different wireless thermometer/hygrometer sensors that we have setup all over the yard to learn more about our specific microclimates.
