Sunday, July 21, 2019

Didn't my figs do better last summer?

Heritage fig trees last July. 
I like to fancy myself a sort of  a "citizen scientist." Well, I like to take a lot of pics of the plants in my yard to see how they are faring in our hot, dry summer...

This morning I was scrolling down Google Photos. My heart just sunk as I noticed that our yard looked greener in summers past. For sure our "drought tolerant" heritage fig trees were doing better.

Here is that fig tree now...

Heritage fig in greywater basin. Coming back a little since the rain. (Those are bean sprouts I planted for added nitrogen.)
Why is our little fig struggling so?  Dan claims it's not even as hot this summer. But he did say that last year the monsoon rains had started by now...  It can't be just the lack of water, because our fig trees are watered regularly by greywater from our washing machine... Maybe the rain clouds give some relief from the scorching sun...?

I got to thinking. I wonder if it's because it's not cooling off at night like it used to. One evening it got  up to 92 degrees! It wasn't always like this. Before there was air-conditioning people in Tucson used to sleep outside to cool off in the summer.

Some plants (and us humans) need that cooling down time to recover from the hot day. It is vital for our health.

Typical profile of the Phoenix urban heat island (UHI) using the five predominant land types
This phenomenon where it stays hot at night is known as the "Urban Heat Island Effect." All of the pavement and cement in our city holds the heat longer. Phoenix has a real problem with this. I wasn't planning to blog about that this morning. But I am concerned that some people want to make Tucson more like Phoenix with more highways going through town! Our small town infrastructure is a blessing! It is one of the reasons it's cooler here!

One way to fight the heat island effect is to plant more trees. And the city is working on that. Mayor Rothschild championed the 10,000 Trees Campaign. That's great because trees cool down our streets and neighborhoods AND sequester carbon to fight climate change. We could sure use some of those trees to line the sidewalks so people have a shady place to walk or wait for the bus.

As we plant all those trees, we need to be mindful of how much water the trees take and where we are getting the water for them. We are living in a desert during a drought.  As much as we love to grow fruit trees, they require more water. To be sustainable, we need to plant more drought tolerant heritage fruit trees or native trees - and use our wash-water and rainwater to irrigate them.

For our part, we dug out most of the gravel in our yard. We planted "durable," heritage pomegranate and fig trees in a mulch-filled  greywater basin and edible native trees in the front yard. (The mulch works with the roots of native grasses to hold the moisture longer). We water the fruit trees mostly with greywater from our washing machine and rainwater collected in the basin. In the summer, I might give them a little extra water from our 55 gallon rain barrels.

Last Sunday we had our first summer shower. Yeah! I try to use up all the water in the blue barrels before the next rain, so they are ready to be filled up again.  I try to do it first thing in the morning before it gets hot and the water evaporates.

We still aren't doing everything we can do. We plan to install more gutters on our roof to direct more rainwater into bigger cisterns and use rainwater from the neighbors roof to water a vegetable garden. (It helps to have a good relationship with your neighbors!) 

To stop the Urban Heat Island Effect, it's gonna take a community effort. We're all gonna have to plant more trees (and maybe drive a little less so we can dig up some parking lot pavement). Right now, there is enough rainwater to irrigate them all, if we all do rainwater harvesting. There are rainwater harvesting rebates and a low income grant and loan program - yet less than 1% of us are taking advantage of them. Why is that? What can we do about it?  I would love to hear your ideas and solutions.

Meanwhile, we can start where we are. Take the first steps. Plant a tree. Start a conversation with your neighbors. Share this blog... :)


  1. Its more the gravel than anything, my Grandma has the only yard with gravel on her street and its literally 15 degrees warmer in her yard and house, the neighbor next door has grass front and back and its easily 20 degrees cooler late at night. I live right by the desert and it almost feels chilly in the desert, whereas its 90 degrees in the neighborhood which is your typical HOA ugly gravel yards type neighborhood.

    Gravel is the most unnatural thing there is besides asphalt and cement. If the city retroactively banned gravel, it would make a huge difference by itself.

  2. Thanks for the informative article, I hope enough people come together one day to make some changes for the betterment of the community.