Let’s say you just planted an avocado tree from a five-gallon container, the typical size available at nurseries. How should you water this tree?
First, immediately after planting you should water lavishly, making sure that all of the container soil is wet and also making sure that the surrounding native soil is also wet to a couple feet away from the tree and a couple feet deep. You’re likely going to need to apply about 10 gallons to do this.
Why water the container soil? Because that’s where the tree’s roots are. Why water the surrounding soil when the tree’s roots are only in the container soil? Because if the surrounding native soil is dry, it will literally suck water from the container soil, leaving the tree’s roots thirsty.
It doesn’t much matter what materials or method you use to water the tree, from that first watering through the entire first year. (Which watering method is best in the long run? Probably sprinklers, not drip. See why on page 19 of this avocado-growing handbook.) Watering by hand with a can or a hose is fine, watering by drip emitters can work fine as long as the emitters are close to the trunk and directly on top of the container soil, and a sprinkler works great too.
This micro-sprinkler made by Philmac is my favorite because it can be used on baby trees, as it is here, by popping off the spinner and inserting a deflector which turns it into a little spitter.
Just be sure that you’re watering the container soil consistently while also watering the surrounding native soil occasionally. This might mean that you put automated irrigation on the container soil and then hand-water the surrounding native soil every couple weeks.
How often is “consistently”? And how much should you water each time? Let’s be as specific as possible.
For a tree planted in spring or early fall:
- Week 1- water every other day, 2 gallons each time
- Week 2- water every three days, 3 gallons each time
- Weeks 3/4- water every four days, 4 gallons each time
For a tree planted in summer:
- Week 1- water every day, 1 gallon each time
- Week 2- water every other day, 2 gallons each time
- Weeks 3/4- water every three days, 4 gallons each time
For a tree planted in late fall or winter:
- Week 1- water every three days, 2 gallons each time
- Week 2- water every four days, 2 gallons each time
- Weeks 3/4- water every five days, 3 gallons each time
In summary, you’ll water frequently at first and then less often as time goes on. This is because the tree will eventually grow its roots into the surrounding native soil and have more stamina because of the larger root system.
After the first month — no matter which season — your regular waterings should no longer only be over the container soil but also over the surrounding native soil. Why? Because the tree will have started extending its roots there after about a month from planting.
Remember that your baby avocado tree uses water in part based on the weather conditions. If there’s an extreme heat wave soon after planting, you may have to water every day. Likewise, if there are storms every week during winter, you’ll not need to water at all. But there could also be warm, dry Santa Anas in winter which make your new avocado tree want water every few days despite the winter season.
After the tree’s first full winter it can be considered established, no longer new, meaning it has extended its roots into the native soil and therefore your watering will more closely approximate the schedule it needs for the rest of its life.
In general, established avocado trees like to be watered every five to ten days, but that’s another topic: See this resource from Gary Bender for how to water an established avocado tree. Look at page 2 and also at the table at the end on page 7.
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It’s January 2016, and according to plan, we’ve got a new rain tank for the new year.
Our idea has been to install one new tank each year and make improvements wherever possible regarding the size, location, and distribution of the collected rainwater.
We got some things right with the first tank we put in last year, and so have imitated those aspects. They include the tank size, base, and location. This second tank is sized to handle just under four inches of rainfall on its section of roof (865 gallons of capacity for 552 square feet). This tank rests on a slightly raised base of gravel. And the tank is located where it can gravity-feed trees nearby, that is, the tank is close to a number of trees and it is above them in elevation.
There’s really only one thing that I tried with the first tank but abandoned, and that is distributing the water through driplines to nearby avocado trees. The primary benefit of applying rainwater to avocado trees is to leach the salts in the soil. However, water applied through drip emitters is ineffective at this because the water forms a chimney that dives mostly straight down but doesn’t spread laterally very much, thereby not leaching outside of the vertical chimney below the emitter. This is how it goes in my sandy loam soil anyway. So, I’ve learned to distribute the rainwater to avocado trees through a rain wand at the end of a hose, manually. It’s time-consuming, but at least it’s highly effective at distributing the water across the entire root zone of the tree.
On the other side of that coin, I have learned that I can effectively distribute the rainwater from the tank through driplines to most every other plant, vegetables, deciduous, and citrus trees included.
This is why I’ve set up the new rain tank the way I eventually set up the first rain tank: It has two connections where one goes to a hose with a rain wand for the avocados and the other goes to a dripline for vegetables and other fruit trees. Using non-pressure compensating drip emitters allows the rainwater from the tank to be distributed throughout those driplines by gravity alone.
And finally we’re predicted to get some rain! I installed the new tank in December, actually, but that was a dry month. We only got 1.2 inches. Now meteorologists are getting excited by a change in weather patterns. As the California Weather Blog mentions, there is a stream of significant storms finally aimed straight at Southern California. As I write, the first sprinkles are falling. The latest forecast shows precipitation every day for the next five days. The National Weather Service predicts we will have received between two and three inches of rain by the end of the week. The new tank will hold that just fine.
I just picked up our new rain tank from the Bushman factory, and I chose to size it like our first one because that one worked very well last year. (I suppose I got lucky in sizing that first one.) In other words, I chose a size that would hold between three and four inches of rainfall from its particular section of our roof.
Here are the numbers for our first tank, and then I’ll give the parallel numbers for our new one: The first one collects from a 363-square foot section of roof. Four inches of rain on that area equals 872 gallons (363 x 4 x 0.623), but the roof is made of cement tile, and that surface absorbs some of the rain. Some people estimate cement tile to shed 65% of the rain that falls on it. My experience has shown that to be about right. So, four inches of rain on 363 square feet of cement tile roof sheds 567 gallons. Our tank has a capacity of 530 gallons — almost enough to hold that four inches worth of rain.
As for our second tank, it will collect from a 552-square foot section of roof. On this area, a four-inch rain would amount to 1,376 gallons but would shed 894 gallons. The second tank has a capacity of 865 gallons.
Bushman 865-gallon, waiting to be installed.
Why has the first tank — with a capacity to hold between three and four inches of rainfall — worked well? It has to do with how much rain we get and when we get it. Our average annual rainfall is 16 inches, but the wettest three months are what’s important. In January, February, and March, we average around 3.5 inches of rain each month. You might think the tank would fill up by the end of January and then just overflow all February and March; however, what usually happens is that we get a dry spell, often accompanied by warm Santa Ana winds, between the rain storms. Sometimes the dry spell lasts three or four weeks, even in these wettest months. And during these dry spells the collected rain in the tank gets used, at least in part, such that there’s room to collect more rain when the next storm comes.
For example, last winter (2014-2015) the 530-gallon tank was nearly at full capacity after a relatively wet December but then got depleted during a relatively dry January.
Our rain does occasionally come in the form of a four-inch downpour though, or a back-to-back couple of weeks of rainstorms in February that leave us with many inches at once. Here the tank is going to overflow. But this will happen rarely and momentarily. We’ve had one such single downpour in the past two years (February 2014) and no back-to-back rainstorms (though I expect some during this El Nino winter). True, if the tank were bigger it would be able to handle these rare deluges, but it would also rarely use its capacity, and that to me seems a larger waste.
A capacity of between three and four inches is big enough to rarely overflow yet small enough to have little empty space through the normal wet winter months.
We moved in to our new house with the goal of spending no more than $50 per month on water while growing 80% of our fruits and vegetables. Last summer (2014) we got close to getting 80% of the produce we eat from our yard, but each time a water bill came I was shattered. One month last summer reached $108. I started to think that $50 per month was unrealistically low. This summer, however, has just ended on a more promising note.
From May 20 to July 20 of this summer we used 55% less water compared to 2014. That was 9,724 gallons compared to 21,692 gallons in 2014. And from July 20 to September 20 we used 39% less water compared to the same period in 2014, or 8,228 gallons compared to 13,464 gallons in 2014. So on average we reduced our summer water use by 47%, or to round off, we cut our use in half.
The important thing to note is that the production from the yard has remained basically the same while reducing our use of water. Our freezer is currently full of tomatoes from the yard, there are more peppers still in the garden than we could ever consume, the avocado trees are carrying fruit, we ate dozens of apricots in June, it’s almost time to start harvesting the sweet potatoes, the orange tree has hundreds of fruit for next summer, etc. So why and how?
The main reason, I believe, is the switch of irrigation methods from overhead sprinkler to drip. Last summer almost everything was watered with sprinklers, but this summer every single plant has been watered with drip. In the vegetable beds alone, which cover about 1,100 square feet, I estimate that I used about half the amount of water that I did last year because with last summer’s sprinklers I was watering paths and other areas where plant roots didn’t reach. This was a waste.
With the drip lines this summer I have been much more efficient since there is no more watering of paths, and also I can apply different amounts of water to different sections of the vegetable beds. For example, once the rows of onions had bulbed out in early May I closed the valves on their drip lines and let them mature using only the residual moisture in the soil. This saved weeks’ worth of water to those rows. With the overhead sprinkler of the past, this sort of nuanced application of water to specific rows of vegetables had been impossible.
In addition to the help of increased efficiency attained through using drip irrigation, we got plain old lucky this summer compared to last summer. We were blessed with two significant summer rains — so rare for Southern California. On July 18 and 19 we got 1.65 inches, and then on September 15 we got 1.5 inches. It was actually the wettest summer on record for San Diego, although that fact can be misleading if you don’t remember that summers in San Diego are normally without any precipitation.
These unexpected summer rains not only fed the plants but also filled up the rainwater tank. As of this date, the last day of September, I have still not emptied the rainwater in the tank. It’s even possible that we’ll get our first fall rain before I use all of that stored rain. Back in the spring, I had never imagined such a scenario.
Nevertheless, we have had an exceptionally hot summer. According to the National Weather Service, most of Southern California had a September that was about 5% warmer than normal.
Going forward, I’m wondering if I should continue to aim at keeping our monthly water bills at an average of $50. For 2015 so far, our average has been $58.15. This comprises the high-use summer months offset by the low-use winter months. (This includes yard water and household water, by the way.) It now seems possible to reach that $50 average.
However, I’m thinking I should alter the goal from a dollar amount to a certain number of gallons since that’s really all I have control of. The dollar amount is largely controlled by the rates the water district decides to charge, and I have no say in that matter. Moreover, the water district has increased the rate three times in the last two years. Today, our rates are about 25% higher than they were when we moved in, in 2013. Surely, that trend will continue.
How about a new goal of averaging 4,000 gallons per month for the year?
This is Puleng, one of my former students in Lesotho. I learned to wash by hand from her and other students at Ngoana Jesu Secondary School, and I also learned from them to reuse my laundry water on my vegetable plots. I adopted that practice in Lesotho, and I’ve been trying to adapt it to my new context in Southern California.
Here I use a machine to do the washing, and I reuse the laundry water by directing it through a hose to a Chinese pistache tree.
But in getting from the Lesotho method to this California method, I made a few mistakes along the way.
When we moved into our house — almost two years ago, now — I disconnected the hose behind the washer so that instead of emptying into the sewer line I could empty it into a trash can. I then used a bucket to distribute that water to our burgeoning vegetable garden. It took a lot of time to distribute that water, however. The washing machine used more than three times as much (each load used between 15 and 30 gallons whereas in Lesotho each load used between 4 and 7 gallons).
So last spring I bought an extension for the machine’s plastic hose. I planted tomatoes, squashes, and melons in four groups along the driveway, fairly close to the washing machine, and I placed the end of the hose near one of the groups of plants each time we did a load. The plan was to water all of those plants with laundry water alone. Then the plants started dying. The young squash plants started showing symptoms first. The margins of their leaves looked burnt, and the plants grew very slowly in general. Next the tomatoes demonstrated toxicity. They screamed toxicity! Their leaves yellowed, purpled, curled, they stopped setting fruit, and so I yanked them out of the ground.
We had already switched to using the least toxic detergent we could find (Ecos brand), so then we cut back on the amount of that detergent we were using. It was all too late. The soil had been spoiled and the plants were goners.
I thought about why these vegetables were killed by my laundry water while my vegetables in Lesotho had thrived under an apparently similar regimen. Turns out they weren’t similar regimens.
In Lesotho, I often dumped the wash water in the bushes and only the rinse water on my vegetable plots. Yet here in California I was dumping both, so it added potentially harmful chemicals in higher concentrations. But more than that, I hadn’t used as much detergent in Lesotho in the first place. When washing by hand, you see how soiled each article of clothing is and you only apply as much detergent as is absolutely necessary. Having to work with your hands in such a detergent solution encourages you to use as little as possible because the skin on your fingers and palms get tight and painful if you use a lot. Now using the machine, we were just unthinkingly following the recommendation of the detergent manufacturer (“fill to this line”) and thereby adding much more detergent than we had while washing by hand in Lesotho — this even though the Ecos brand ingredients were much less toxic than the ingredients of the Surf brand that we used in Lesotho.
Another difference that occurred to me was that in Lesotho it rained all summer. There were thunderstorms which consistently leached the laundry water through the soil profile. In addition to that, when the rains failed, I watered my vegetables with collected rain off my roof and the school buildings’ roofs, as well as groundwater from a borehole pump. Yet here I was in California giving my vegetables a steady diet of nothing but laundry water.
Therefore, we come to our current method of reusing laundry water in the yard in Southern California.
For almost a year now, I have experienced excellent results by connecting a short extension hose (15 feet long) to the washing machine and snaking it under the Chinese pistache tree behind the garage. This tree receives additional rainwater all winter from the runoff from the nearby concrete porch as well as two roof downspouts, and thus the soil gets a leaching similar to what my Lesotho soil received. We place the hose near the spots where the porch and downspouts concentrate their rain runoff.
Whatever chemicals build up over the summer from laundry water (sodium is the particular chemical in Ecos detergent that I’m worried about) will be leached by the rinsing of clean rainwater through the winter. That’s the theory, anyway. So far it seems to be working out based on the fine appearance and new growth of the tree.
After we’ve finished with each laundry load, we hang the hose extension on the wall so it drains completely. This ensures that there is never any bad smell — for even a little laundry water sitting in a pipe will start to stink.
Why haven’t I installed permanent piping to direct the laundry water to the pistache tree? Seems like that would save the time of having to connect the flexible hose before each load and then having to hang it back up afterward. True, it would save that time, but that time adds up to literally five seconds. The task is so quick and not annoying that we don’t even think about it anymore.
But more importantly, there is only a single inch of fall between the level of the concrete porch and the soil surface beneath the pistache tree. Therefore, pipes would have to open into holes dug deep enough such that the pipes are sloped enough to drain completely. These holes would need to be maintained so they don’t clog the pipe outlets.
The permanent system would save the few seconds we spend connecting and disconnecting the flexible hose at the expense of the time and resources it would take to install (cut concrete, buy and lay pipe, dig outlet holes, etc.) plus maintain. As for now, the flexible hose method requires zero maintenance, has no chance of becoming clogged, and yet remains adaptable to additional plantings we might make in that part of the yard in the future.
Yesterday, we got an unusually strong storm for mid-May. My yard received 0.7 inches; but the San Diego Airport got 1.84 inches! For San Diego, that’s the wettest day in May ever, according to the National Weather Service. For the whole Southern California region, we are approaching record levels of rainfall for the month of May — and it’s only halfway into the month. But what have we made of this blessing?
Rain is good, right? We all talk of appreciating it, even needing it in this era of drought.
Then why is my house designed to deal with rain as if it’s sewage? Gutters take the rain from my roof and direct them into downspouts and then into pipes underground which emit the water into the road. Or some of the gutters empty into downspouts that direct the water onto the driveway which then vomits the rain into the road. Getting rid of something is treating it like waste.
Actually, on second thought, my house treats waste — sewage — better than it treats rain, since the sewer pipes feed into a septic tank and leach lines, and therefore keeps my sewage on my property. My house is designed to move rain farther away from it than it moves the sewage.
Is your house any different? Maybe your sewer lines are connected to a municipal sewer system instead of a septic tank, but I’d guess your house treats rain like waste all the same. It is the default design for houses in Southern California, not to mention all other buildings as well as parking lots. We move the rain off-site, into streets and storm drains — and then we lament the drought.
I lament that I have to labor to alter this improvident, default design. I have redirected roof downspouts to the root zones of trees, cut driveway curbs to infiltrate its runoff, installed rain tanks, etc. Why isn’t treating rain like this, like it’s a resource, the default design?
I’m sincerely asking the question. I don’t know the reasons.